Competition

@article{beauchamp1932competitive2,
    author = "Beauchamp, R. S. A. and Ullyott, P",
    title = "Competitive relationships between certain species of fresh-water triclads",
    year = "1932",
    journal = "Journal of Ecology, v. 20, p. 200- 208",
    note = "talkorigins\_source = {true}; raw\_reference = {Beauchamp, R. S. A., and Ullyott, P., 1932, Competitive relationships between certain species of fresh-water triclads: Journal of Ecology, v. 20, p. 200- 208.}"
}

@article{elton1946competition12,
    author = "Elton, C. S",
    title = "Competition and the structure of ecological communities",
    year = "1946",
    journal = "Journal of Animal Ecology, v. 15, p. 54-68",
    note = "talkorigins\_source = {true}; raw\_reference = {Elton, C. S., 1946, Competition and the structure of ecological communities: Journal of Animal Ecology, v. 15, p. 54-68.}"
}

@article{crombie1947interspecific8,
    author = "Crombie, A. C",
    title = "Interspecific competition",
    year = "1947",
    journal = "Journal of Animal Ecology, v. 16, p. 44-73",
    note = "talkorigins\_source = {true}; raw\_reference = {Crombie, A. C., 1947, Interspecific competition: Journal of Animal Ecology, v. 16, p. 44-73.}"
}

@article{andrewartha1953the1,
    author = "Andrewartha, H. G. and Birch, L. C",
    title = "The Lotka-Volterra theory of interspecific competition",
    year = "1953",
    journal = "Aust. Journal Zoology, v. 1, p. 174-177",
    note = "talkorigins\_source = {true}; raw\_reference = {Andrewartha, H. G., and Birch, L. C., 1953, The Lotka-Volterra theory of interspecific competition: Aust. Journal Zoology, v. 1, p. 174-177.}"
}

@misc{birch1957the3,
    author = "Birch, L. C",
    title = "The meanings of competition",
    year = "1957",
    howpublished = "American Naturalist, v. 91, p. 5-18",
    note = "talkorigins\_source = {true}; raw\_reference = {Birch, L. C., 1957, The meanings of competition: American Naturalist, v. 91, p. 5-18.}"
}

@misc{cole1960competitive5,
    author = "Cole, L. C",
    title = "Competitive exclusion",
    year = "1960",
    howpublished = "Science, v. 132, p. 348-349",
    note = "talkorigins\_source = {true}; raw\_reference = {Cole, L. C., 1960, Competitive exclusion: Science, v. 132, p. 348-349.}"
}

In summary, then, our general conclusions are: (1) Populations of producers, carnivores, and decomposers are limited by their respective resources in the classical density-dependent fashion. (2) Interspecific competition must necessarily exist among the members of each of these three trophic levels. (3) Herbivores are seldom food-limited, appear most often to be predator-limited, and therefore are not likely to compete for common resources.

@article{doi101086282146,
    author = "Hairston, Nelson G. and Smith, Frederick E. and Slobodkin, Lawrence B.",
    title = "Community Structure, Population Control, and Competition",
    year = "1960",
    journal = "The American Naturalist",
    abstract = "In summary, then, our general conclusions are: (1) Populations of producers, carnivores, and decomposers are limited by their respective resources in the classical density-dependent fashion. (2) Interspecific competition must necessarily exist among the members of each of these three trophic levels. (3) Herbivores are seldom food-limited, appear most often to be predator-limited, and therefore are not likely to compete for common resources.",
    url = "https://doi.org/10.1086/282146",
    doi = "10.1086/282146",
    openalex = "W2004827430",
    references = "beauchamp1932competitive, doi101101sqb195702201017, doi101101sqb195702201021, doi101111j155856461957tb02883x, doi101111j174966321948tb39854x, doi1023071395, doi1023071485, doi1023071931600, doi1023071943584, doi1023072240"
}

@misc{connell1961the6,
    author = "Connell, J. H",
    title = "The influence of interspecific competition and other factors on the distribution of the barnacle, Chthamalus stellatus",
    year = "1961",
    howpublished = "Ecology, v. 42, p. 710-723",
    note = "talkorigins\_source = {true}; raw\_reference = {Connell, J. H., 1961, The influence of interspecific competition and other factors on the distribution of the barnacle, Chthamalus stellatus: Ecology, v. 42, p. 710-723.}"
}

@misc{connell1961the7,
    author = "Connell, J. H",
    title = "The influence of interspecific competition and other factors on the distribution of the barnacle, Chthamalus stellatus",
    year = "1961",
    howpublished = "Ecology, v. 42, p. 710-723",
    note = "talkorigins\_source = {true}; raw\_reference = {Connell, J. H., 1961, The influence of interspecific competition and other factors on the distribution of the barnacle, Chthamalus stellatus: Ecology, v. 42, p. 710-723.}"
}

@misc{crowell1962reduced9,
    author = "Crowell, K. L",
    title = "Reduced interspecific competition among the birds of Bermuda",
    year = "1962",
    howpublished = "Ecology, v. 43, p. 75-88",
    note = "talkorigins\_source = {true}; raw\_reference = {Crowell, K. L., 1962, Reduced interspecific competition among the birds of Bermuda: Ecology, v. 43, p. 75-88.}"
}

@article{debach1966the11,
    author = "DeBach, P",
    title = "The competitive displacement and coexistance principles",
    year = "1966",
    journal = "Annual Review of Entomology, v. 11, p. 183-212",
    note = "talkorigins\_source = {true}; raw\_reference = {DeBach, P., 1966, The competitive displacement and coexistance principles: Annual Review of Entomology, v. 11, p. 183-212.}"
}

An understanding of community structure should be based on evidence that the growth and regulation of the component populations in the community are affected in a predictable manner by natural physical disturbances and by interactions with other species in the community. This study presents an experimental evaluation of the effects of such disturbances and competitive interactions on populations of sessile organisms in the rocky intertidal community, for which space can be demonstrated to be the most important limiting resource. This research was carried out at eight stations on the Washington coastline which have been ranked according to an exposure/desiccation gradient and subjected to comparable manipulation and observation. Physical variables such as wave exposure, battering by drift logs, and desiccation have important effects on the distribution and abundance of many of the sessile species in the community. In particular, wave exposure and desiccation have a major influence on the distribution patterns of all the algae and of the anemone Anthopleura elegantissima. The probability of damage from drift logs is very high in areas where logs have accumulated along the intertidal. Log damage and wave exposure have complementary effects in the provision of free space in a mussel bed, as wave shock enlarges a patch created by log damage by wrenching the mussels from the substratum at the periphery of the bare patch. Competition for primary space results in clear dominance hierarchies, in which barnacles are dominant over algae. Among the barnacles, Balanus cariosus is dominant over both B. glandula and Chthamalus dalli; B. glandula is dominant over C. dalli. The mussel Mytilus californianus requires secondary space (certain algae, barnacles, or byssal threads) for larval settlement, but is capable of growing over all other sessile species and potentially is the competitive dominant of space in the community.

@article{dayton1971competition,
    author = "Dayton, Paul K.",
    title = "Competition, Disturbance, and Community Organization: The Provision and Subsequent Utilization of Space in a Rocky Intertidal Community",
    year = "1971",
    journal = "Ecological Monographs",
    abstract = "An understanding of community structure should be based on evidence that the growth and regulation of the component populations in the community are affected in a predictable manner by natural physical disturbances and by interactions with other species in the community. This study presents an experimental evaluation of the effects of such disturbances and competitive interactions on populations of sessile organisms in the rocky intertidal community, for which space can be demonstrated to be the most important limiting resource. This research was carried out at eight stations on the Washington coastline which have been ranked according to an exposure/desiccation gradient and subjected to comparable manipulation and observation. Physical variables such as wave exposure, battering by drift logs, and desiccation have important effects on the distribution and abundance of many of the sessile species in the community. In particular, wave exposure and desiccation have a major influence on the distribution patterns of all the algae and of the anemone Anthopleura elegantissima. The probability of damage from drift logs is very high in areas where logs have accumulated along the intertidal. Log damage and wave exposure have complementary effects in the provision of free space in a mussel bed, as wave shock enlarges a patch created by log damage by wrenching the mussels from the substratum at the periphery of the bare patch. Competition for primary space results in clear dominance hierarchies, in which barnacles are dominant over algae. Among the barnacles, Balanus cariosus is dominant over both B. glandula and Chthamalus dalli; B. glandula is dominant over C. dalli. The mussel Mytilus californianus requires secondary space (certain algae, barnacles, or byssal threads) for larval settlement, but is capable of growing over all other sessile species and potentially is the competitive dominant of space in the community.",
    url = "https://doi.org/10.2307/1948498",
    doi = "10.2307/1948498",
    number = "4",
    openalex = "W1974072473",
    pages = "351-389",
    volume = "41",
    references = "connell1961effects, doi101086282400, doi101086282455, doi101126science1473655250, doi1023071931746, doi1023071933500, doi1023071936888, doi1023071942327, doi1023073498751, doi102307jctvx5wbbh"
}

@misc{dayton1971competition10,
    author = "Dayton, P. K",
    title = "Competition, disturbance and community organization",
    year = "1971",
    howpublished = "the provision and subsequent utilization of space in a rocky intertidal community: Ecological Monographs, v. 41, p. 351-389",
    note = "talkorigins\_source = {true}; raw\_reference = {Dayton, P. K., 1971, Competition, disturbance and community organization: the provision and subsequent utilization of space in a rocky intertidal community: Ecological Monographs, v. 41, p. 351-389.}"
}

@book{cody1973competition4,
    author = "Cody, M. L",
    title = "Competition and Community Structure",
    year = "1973",
    publisher = "Princeton, New Jersey, Princeton University Press",
    note = "talkorigins\_source = {true}; raw\_reference = {Cody, M. L., 1973, Competition and Community Structure: Princeton, New Jersey, Princeton University Press.}"
}

@article{doi101007bf00345739,
    author = "Paine, Robert T.",
    title = "Intertidal community structure",
    year = "1974",
    journal = "Oecologia",
    url = "https://doi.org/10.1007/bf00345739",
    doi = "10.1007/bf00345739",
    openalex = "W75209568",
    references = "dayton1971competition, doi101086282400, doi101086282541, doi101146annureves03110172001125, doi1023071931746, doi1023071933500, doi1023071936888, doi1023071942327, doi1023071942404, doi104319lo19691450710, openalexw1538256544, openalexw2418669733"
}

To understand resource partitioning, essentially a community phenomenon, we require a holistic theory that draws upon models at the individual and population level. Yet some investigators are still content mainly to document differences between species, a procedure of only limited interest. Therefore, it may be useful to conclude with a list of questions appropriate for studies of resource partitioning, questions this article has related to the theory in a preliminary way. 1) What is the mechanism of competition? What is the relative importance of predation? Are differences likely to be caused by pressures toward reproductive isolation? 2) Are niches (utilizations) regularly spaced along a single dimension? 3) How many dimensions are important, and is there a tendency for more dimensions to be added as species number increases? 4) Is dimensional separation complementary? 5) Which dimensions are utilized, how do they rank in importance, and why? How do particular dimensions change in rank as species nuimber increases? 6) What is the relation of dimensional separation to difference in phenotypic indicators? To what extent does the functional relation of phenotype to resource characteristics constrain partitioning? 7) What is the distance between mean position of niches, what is the niche standard deviation, and what is the ratio of the two? What is the niche shape?

@article{doi101126science185414527,
    author = "Schoener, Thomas W.",
    title = "Resource Partitioning in Ecological Communities",
    year = "1974",
    journal = "Science",
    abstract = "To understand resource partitioning, essentially a community phenomenon, we require a holistic theory that draws upon models at the individual and population level. Yet some investigators are still content mainly to document differences between species, a procedure of only limited interest. Therefore, it may be useful to conclude with a list of questions appropriate for studies of resource partitioning, questions this article has related to the theory in a preliminary way. 1) What is the mechanism of competition? What is the relative importance of predation? Are differences likely to be caused by pressures toward reproductive isolation? 2) Are niches (utilizations) regularly spaced along a single dimension? 3) How many dimensions are important, and is there a tendency for more dimensions to be added as species number increases? 4) Is dimensional separation complementary? 5) Which dimensions are utilized, how do they rank in importance, and why? How do particular dimensions change in rank as species nuimber increases? 6) What is the relation of dimensional separation to difference in phenotypic indicators? To what extent does the functional relation of phenotype to resource characteristics constrain partitioning? 7) What is the distance between mean position of niches, what is the niche standard deviation, and what is the ratio of the two? What is the niche shape?",
    url = "https://doi.org/10.1126/science.185.4145.27",
    doi = "10.1126/science.185.4145.27",
    openalex = "W2034690972",
    references = "doi101016s0065250408603190, doi101073pnas6951109, doi101086282070, doi101086282146, doi101086282400, doi101086282454, doi101086282505, doi101086282531, doi101111j109583121972tb00690x, doi101111j1469185x1965tb00815x, doi101126science1473655250, doi101126science16338741419, doi101126science1794075759, doi101146annureves02110171002101, doi1023071931600, doi1023071933181, doi1023071933500, doi1023071935534, doi1023071936893, doi1023071942327, doi1023072411924, doi104039ent913857, doi107312pric91844"
}

A three-species Lotka-Volterra competition community may exhibit population oscillations of a neutral or undamped nature. Nontransitive interference competition, in which 1 can exclude 2, 2 can exclude 3, but 3 can exclude 1, is the underlying mechanism. If immigration, incomplete spatial overlap, or any other mechanism prevents extinction, then such a three-species system must go into true limit cycles. For higher-dimension systems, limit cycles are more likely in communities with an odd number of species. Such limit cycles are most likely to be found in the tropics. A cautionary moral is given: simple competition systems that appear to be unstable and random may be stable and deterministic.

@article{doi101086282973,
    author = "Gilpin, Michael E.",
    title = "Limit Cycles in Competition Communities",
    year = "1975",
    journal = "The American Naturalist",
    abstract = "A three-species Lotka-Volterra competition community may exhibit population oscillations of a neutral or undamped nature. Nontransitive interference competition, in which 1 can exclude 2, 2 can exclude 3, but 3 can exclude 1, is the underlying mechanism. If immigration, incomplete spatial overlap, or any other mechanism prevents extinction, then such a three-species system must go into true limit cycles. For higher-dimension systems, limit cycles are more likely in communities with an odd number of species. Such limit cycles are most likely to be found in the tropics. A cautionary moral is given: simple competition systems that appear to be unstable and random may be stable and deterministic.",
    url = "https://doi.org/10.1086/282973",
    doi = "10.1086/282973",
    openalex = "W2020264308"
}

@article{doi1010160040580977900429,
    author = "Holt, Robert D.",
    title = "Predation, apparent competition, and the structure of prey communities",
    year = "1977",
    journal = "Theoretical Population Biology",
    url = "https://doi.org/10.1016/0040-5809(77)90042-9",
    doi = "10.1016/0040-5809(77)90042-9",
    openalex = "W2024882325",
    references = "doi1010160040580970900390, doi101016s0065250408602883, doi101038116461b0, doi101038260204c0, doi101086282146, doi101086282400, doi101086282415, doi101086282477, doi101126science150369228, doi101126science185414527, doi10129879780300188479022, doi1015159780691206912, doi1023072258550, doi1023072298330, doi1023072965538, openalexw2971318137"
}

SUMMARY According to ‘Gause's hypothesis’ a corollary of the process of evolution by natural selection is that in a community at equilibrium every species must occupy a different niche. Many botanists have found this idea improbable because they have ignored the processes of regeneration in plant communities. Most plant communities are longer‐lived than their constituent individual plants. When an individual dies, it may or may not be replaced by an individual of the same species. It is this replacement stage which is all‐important to the argument presented. Several mechanisms not involving regeneration also contribute to the maintenance of species‐richness: differences in life‐form coupled with the inability of larger plants to exhaust or cut off all resources, also the development of dependence‐relationships, differences in phenology coupled with tolerance of suppression, fluctuations in the environment coupled with relatively small differences in competitive ability between many species, the ability of certain species‐pairs to form stable mixtures because of a balance of intraspecific competition against interspecific competition, the production of substances more toxic to the producer‐species than to the other species, differences in the primary limiting mineral nutrients or pore‐sizes in the soil for neighbouring plants of different soecies, and differences in the competitive abilities of species dependent on their physiological age coupled with the uneven‐age structure of many populations. The mechanisms listed above do not go far to explain the indefinite persistence in mixture of the many species in the most species‐rich communities known. In contrast there seem to be almost limitless possibilities for differences between species in their requirements for regeneration, i.e. the replacement of the individual plants of one generation by those of the next. This idea is illustrated for tree species and it is emphasized that foresters were the first by a wide margin to appreciate its importance. The processes involved in the successful invasion of a gap by a given plant species and some characters of the gap that may be important are summarized in Table 2. The definition of a plant's niche requires recognition of four components: the habitat niche, the life‐form niche, the phenological niche, and the regeneration niche. A brief account is given of the patterns of regeneration in different kinds of plant community to provide a background for studies of differentiation in the regeneration niche. All stages in the regeneration‐cycle are potentially important and examples of differentiation between species are given for each of the following stages: Production of viable seed (including the sub‐stages of flowering, pollination and seed‐set), dispersal, in space and time, germination, establishment, and further development of the immature plant. In the concluding discussion emphasis is placed on the following themes: the kinds of work needed in future to prove or disprove that differentiation in the regeneration niche is the major explanation of the maintenance of species‐richness in plant communities, the relation of the present thesis to published ideas on the origin of phenological spread, the relevance of the present thesis to the discussion on the presence of continua in vegetation, the co‐incidence of the present thesis and the emerging ideas of evolutionists about differentiation of angiosperm taxa, and the importance of regeneration‐studies for conservation.

@article{doi101111j1469185x1977tb01347x,
    author = "Grubb, P. J.",
    title = "THE MAINTENANCE OF SPECIES‐RICHNESS IN PLANT COMMUNITIES: THE IMPORTANCE OF THE REGENERATION NICHE",
    year = "1977",
    journal = "Biological reviews/Biological reviews of the Cambridge Philosophical Society",
    abstract = "SUMMARY According to ‘Gause's hypothesis’ a corollary of the process of evolution by natural selection is that in a community at equilibrium every species must occupy a different niche. Many botanists have found this idea improbable because they have ignored the processes of regeneration in plant communities. Most plant communities are longer‐lived than their constituent individual plants. When an individual dies, it may or may not be replaced by an individual of the same species. It is this replacement stage which is all‐important to the argument presented. Several mechanisms not involving regeneration also contribute to the maintenance of species‐richness: differences in life‐form coupled with the inability of larger plants to exhaust or cut off all resources, also the development of dependence‐relationships, differences in phenology coupled with tolerance of suppression, fluctuations in the environment coupled with relatively small differences in competitive ability between many species, the ability of certain species‐pairs to form stable mixtures because of a balance of intraspecific competition against interspecific competition, the production of substances more toxic to the producer‐species than to the other species, differences in the primary limiting mineral nutrients or pore‐sizes in the soil for neighbouring plants of different soecies, and differences in the competitive abilities of species dependent on their physiological age coupled with the uneven‐age structure of many populations. The mechanisms listed above do not go far to explain the indefinite persistence in mixture of the many species in the most species‐rich communities known. In contrast there seem to be almost limitless possibilities for differences between species in their requirements for regeneration, i.e. the replacement of the individual plants of one generation by those of the next. This idea is illustrated for tree species and it is emphasized that foresters were the first by a wide margin to appreciate its importance. The processes involved in the successful invasion of a gap by a given plant species and some characters of the gap that may be important are summarized in Table 2. The definition of a plant's niche requires recognition of four components: the habitat niche, the life‐form niche, the phenological niche, and the regeneration niche. A brief account is given of the patterns of regeneration in different kinds of plant community to provide a background for studies of differentiation in the regeneration niche. All stages in the regeneration‐cycle are potentially important and examples of differentiation between species are given for each of the following stages: Production of viable seed (including the sub‐stages of flowering, pollination and seed‐set), dispersal, in space and time, germination, establishment, and further development of the immature plant. In the concluding discussion emphasis is placed on the following themes: the kinds of work needed in future to prove or disprove that differentiation in the regeneration niche is the major explanation of the maintenance of species‐richness in plant communities, the relation of the present thesis to published ideas on the origin of phenological spread, the relevance of the present thesis to the discussion on the presence of continua in vegetation, the co‐incidence of the present thesis and the emerging ideas of evolutionists about differentiation of angiosperm taxa, and the importance of regeneration‐studies for conservation.",
    url = "https://doi.org/10.1111/j.1469-185x.1977.tb01347.x",
    doi = "10.1111/j.1469-185x.1977.tb01347.x",
    openalex = "W2119259345",
    references = "doi101038242344a0, doi101086282070, doi101086282687, doi101093biomet3812196, doi101111j155856461969tb03489x, doi101126science1473655250, doi1015159780691206912, doi1023071218190, doi1023071929601, doi1023072256497, doi1023072258550, doi1023072989767, openalexw1532540194"
}

Rare until recently, field-experimental studies of interspecific competition now number well over 150. Competition was found in 90% of the studies and 76% of their species, indicating its pervasive importance in ecological systems. Exploitative competition and interference competition were apparent mechanisms about equally often. Few experiments showed year-to-year variation in the existence of competition, though more did in its intensity; many were not long-term. The Hairston-Slobodkin-Smith hypothesis concerning variation in the importance of competition between trophic levels was strongly supported for terrestrial and freshwater systems. In particular, producers, and granivores, nectarivores, carnivores, and scavengers taken together, showed more competition than did phytophagous herbivores and filter feeders. In marine systems, virtually no trend was detectable one way or the other. Large heterotrophs competed more than small ones in most comparisons, and other properties possibly deterring predation, such as stinging behavior, seemed also characteristic of species competing frequently. Among terrestrial plants and certain terrestrial animals but not all, experiments carried out in enclosures were more likely to show competition than unenclosed experiments. A greater ecological overlap implied a greater tendency to compete, as determined experimentally, when niche dimensions were food type or microhabitat; the opposite was true for macrohabitat. A substantial number of studies showed asymmetry in their species' response to competition; larger species were significantly more often superior than smaller ones, though a variety of other apparent reasons for asymmetry also existed. The integration of competition theory into field experimentation has only just begun.

@article{doi101086284133,
    author = "Schoener, Thomas W.",
    title = "Field Experiments on Interspecific Competition",
    year = "1983",
    journal = "The American Naturalist",
    abstract = "Rare until recently, field-experimental studies of interspecific competition now number well over 150. Competition was found in 90\% of the studies and 76\% of their species, indicating its pervasive importance in ecological systems. Exploitative competition and interference competition were apparent mechanisms about equally often. Few experiments showed year-to-year variation in the existence of competition, though more did in its intensity; many were not long-term. The Hairston-Slobodkin-Smith hypothesis concerning variation in the importance of competition between trophic levels was strongly supported for terrestrial and freshwater systems. In particular, producers, and granivores, nectarivores, carnivores, and scavengers taken together, showed more competition than did phytophagous herbivores and filter feeders. In marine systems, virtually no trend was detectable one way or the other. Large heterotrophs competed more than small ones in most comparisons, and other properties possibly deterring predation, such as stinging behavior, seemed also characteristic of species competing frequently. Among terrestrial plants and certain terrestrial animals but not all, experiments carried out in enclosures were more likely to show competition than unenclosed experiments. A greater ecological overlap implied a greater tendency to compete, as determined experimentally, when niche dimensions were food type or microhabitat; the opposite was true for macrohabitat. A substantial number of studies showed asymmetry in their species' response to competition; larger species were significantly more often superior than smaller ones, though a variety of other apparent reasons for asymmetry also existed. The integration of competition theory into field experimentation has only just begun.",
    url = "https://doi.org/10.1086/284133",
    doi = "10.1086/284133",
    openalex = "W2064242117",
    references = "dayton1971competition, doi101016s0065250408603190, doi101038260204c0, doi101086282070, doi101086282146, doi101086282400, doi101086282415, doi101086282477, doi101086282478, doi101086282505, doi1023071933500, doi1023071935707, doi1023071942484, doi1023073280305, doi105962bhltitle4489, openalexw2077454220"
}

In a strictly defined sample of competition studies using controlled field experiments, covering 215 species and 527 experiments, competition was found in most of the studies, in somewhat more than half of the species, and in about two-fifths of the experiments. In most of these experiments interspecific competition was not distinguished from intraspecific competition. In the few studies in which the two were separated, interspecific competition was the stronger form in about onesixth of all experiments done. When competition was demonstrated, intraspecific competition was as strong or stronger than interspecific in three-quarters of the experiments. Some evidence from this literature survey suggests that negative results may be underrepresented, so that the absolute values of these figures may be too high. Since this bias should apply also to studies of all taxa, habitats, or other interactions it should not greatly affect estimates of the relative prevalence of competition. Since these estimates come from field experiments open to other influences such as predators, grazers, weather, disturbances, etc., they should provide a fair approximation of the relative prevalence of interspecific and intraspecific competition in natural ecological communities. The prevalence of competition in these studies varied. Marine organisms showed consistently higher frequencies of competition than terrestrial ones as did large-sized organisms as compared to smaller ones. Plants, herbivores, and carnivores showed similar frequencies of competition in all habitats compared. The incidence of competition varied considerably from year to year and place to place. In some categories, evidence concerning competition is sparse. More studies are needed of all freshwater species, marine vertebrates, parasites, effects on resource partitioning, and particularly the relative strengths of interspecific versus intraspecific competition. When both members of a pair were studied and some competition found, only one member was affected in well over half the experiments. Such strong asymmetrical competition is not always consistent in direction; reversals in the rank order of competitive superiority have been demonstrated by field experiments and direct observations. Some positive interactions were found. These may have been a consequence of actual positive influences or of negative ones acting indirectly through other species. The latter may also apply to some of the negative interactions interpreted as competition in these studies. If only the input and output of an experiment are known, it is difficult to decide what mechanism produced the observed effect. While many of the experiments probably have been correctly interpreted, the present survey illustrates how difficult it is to produce a clear and unambiguous demonstration of interspecific competition.

@article{doi101086284165,
    author = "Connell, Joseph H.",
    title = "On the Prevalence and Relative Importance of Interspecific Competition: Evidence from Field Experiments",
    year = "1983",
    journal = "The American Naturalist",
    abstract = "In a strictly defined sample of competition studies using controlled field experiments, covering 215 species and 527 experiments, competition was found in most of the studies, in somewhat more than half of the species, and in about two-fifths of the experiments. In most of these experiments interspecific competition was not distinguished from intraspecific competition. In the few studies in which the two were separated, interspecific competition was the stronger form in about onesixth of all experiments done. When competition was demonstrated, intraspecific competition was as strong or stronger than interspecific in three-quarters of the experiments. Some evidence from this literature survey suggests that negative results may be underrepresented, so that the absolute values of these figures may be too high. Since this bias should apply also to studies of all taxa, habitats, or other interactions it should not greatly affect estimates of the relative prevalence of competition. Since these estimates come from field experiments open to other influences such as predators, grazers, weather, disturbances, etc., they should provide a fair approximation of the relative prevalence of interspecific and intraspecific competition in natural ecological communities. The prevalence of competition in these studies varied. Marine organisms showed consistently higher frequencies of competition than terrestrial ones as did large-sized organisms as compared to smaller ones. Plants, herbivores, and carnivores showed similar frequencies of competition in all habitats compared. The incidence of competition varied considerably from year to year and place to place. In some categories, evidence concerning competition is sparse. More studies are needed of all freshwater species, marine vertebrates, parasites, effects on resource partitioning, and particularly the relative strengths of interspecific versus intraspecific competition. When both members of a pair were studied and some competition found, only one member was affected in well over half the experiments. Such strong asymmetrical competition is not always consistent in direction; reversals in the rank order of competitive superiority have been demonstrated by field experiments and direct observations. Some positive interactions were found. These may have been a consequence of actual positive influences or of negative ones acting indirectly through other species. The latter may also apply to some of the negative interactions interpreted as competition in these studies. If only the input and output of an experiment are known, it is difficult to decide what mechanism produced the observed effect. While many of the experiments probably have been correctly interpreted, the present survey illustrates how difficult it is to produce a clear and unambiguous demonstration of interspecific competition.",
    url = "https://doi.org/10.1086/284165",
    doi = "10.1086/284165",
    openalex = "W1998245410",
    references = "doi101016b9780127114422x50016, doi101086282146, doi101086282478, doi101086283073, doi101086284133, doi101111j109583121972tb00690x, doi101126science185414527, doi1023071933500, doi1023071935707, doi1023071942404, doi1023071942484, doi1023071942563, openalexw2077454220"
}

@article{doi1023072259756,
    author = "Harper, John L. and Tilman, David",
    title = "Resource Competition and Community Structure.",
    year = "1983",
    journal = "Journal of Ecology",
    url = "https://doi.org/10.2307/2259756",
    doi = "10.2307/2259756",
    openalex = "W2335728124"
}

@article{doi1023074549,
    author = "Hassell, M. P. and Tilman, David",
    title = "Resource Competition and Community Structure",
    year = "1984",
    journal = "Journal of Animal Ecology",
    url = "https://doi.org/10.2307/4549",
    doi = "10.2307/4549",
    openalex = "W3025136633"
}

The species richness (diversity) of local plant and animal assemblages-biological communities-balances regional processes of species formation and geographic dispersal, which add species to communities, against processes of predation, competitive exclusion, adaptation, and stochastic variation, which may promote local extinction. During the past three decades, ecologists have sought to explain differences in local diversity by the influence of the physical environment on local interactions among species, interactions that are generally believed to limit the number of coexisting species. But diversity of the biological community often fails to converge under similar physical conditions, and local diversity bears a demonstrable dependence upon regional diversity. These observations suggest that regional and historical processes, as well as unique events and circumstances, profoundly influence local community structure. Ecologists must broaden their concepts of community processes and incorporate data from systematics, biogeography, and paleontology into analyses of ecological patterns and tests of community theory.

@article{doi101126science2354785167,
    author = "Ricklefs, Robert E.",
    title = "Community Diversity: Relative Roles of Local and Regional Processes",
    year = "1987",
    journal = "Science",
    abstract = "The species richness (diversity) of local plant and animal assemblages-biological communities-balances regional processes of species formation and geographic dispersal, which add species to communities, against processes of predation, competitive exclusion, adaptation, and stochastic variation, which may promote local extinction. During the past three decades, ecologists have sought to explain differences in local diversity by the influence of the physical environment on local interactions among species, interactions that are generally believed to limit the number of coexisting species. But diversity of the biological community often fails to converge under similar physical conditions, and local diversity bears a demonstrable dependence upon regional diversity. These observations suggest that regional and historical processes, as well as unique events and circumstances, profoundly influence local community structure. Ecologists must broaden their concepts of community processes and incorporate data from systematics, biogeography, and paleontology into analyses of ecological patterns and tests of community theory.",
    url = "https://doi.org/10.1126/science.235.4785.167",
    doi = "10.1126/science.235.4785.167",
    openalex = "W1966081590",
    references = "crowell1962reduced, doi101016s0065250408603190, doi101038260204c0, doi101073pnas6951109, doi101086282070, doi101086282398, doi101086282505, doi101086282762, doi101086283366, doi101111j1469185x1965tb00815x, doi101111j155856461960tb03057x, doi101111j155856461963tb03295x, doi101126science19943351302, doi101126science20343871299, doi1023071932042, doi1023071934090, doi1023072257385, doi1023072406825, doi1023072407089, doi1023073544021, openalexw1989371375"
}

Although ecologists have long considered morphology and life history to be important determinants of the distribution, abundance, and dynamics of plants in nature, this book contains the first theory to predict explicitly both the evolution of plant traits and the effects of these traits on plant community structure and dynamics. David Tilman focuses on the universal requirement of terrestrial plants for both below-ground and above-ground resources. The physical separation of these resources means that plants face an unavoidable tradeoff. To obtain a higher proportion of one resource, a plant must allocate more of its growth to the structures involved in its acquisition, and thus necessarily obtain a lower proportion of another resource. Professor Tilman presents a simple theory that includes this constraint and tradeoff, and uses the theory to explore the evolution of plant life histories and morphologies along productivity and disturbance gradients. The book shows that relative growth rate, which is predicted to be strongly influenced by a plant's proportional allocation to leaves, is a major determinant of the transient dynamics of competition. These dynamics may explain the differences between successions on poor versus rich soils and suggest that most field experiments performed to date have been of too short a duration to allow unambiguous interpretation of their results.

@article{doi105860choice260924,
    title = "Plant strategies and the dynamics and structure of plant communities",
    year = "1988",
    journal = "Choice Reviews Online",
    abstract = "Although ecologists have long considered morphology and life history to be important determinants of the distribution, abundance, and dynamics of plants in nature, this book contains the first theory to predict explicitly both the evolution of plant traits and the effects of these traits on plant community structure and dynamics. David Tilman focuses on the universal requirement of terrestrial plants for both below-ground and above-ground resources. The physical separation of these resources means that plants face an unavoidable tradeoff. To obtain a higher proportion of one resource, a plant must allocate more of its growth to the structures involved in its acquisition, and thus necessarily obtain a lower proportion of another resource. Professor Tilman presents a simple theory that includes this constraint and tradeoff, and uses the theory to explore the evolution of plant life histories and morphologies along productivity and disturbance gradients. The book shows that relative growth rate, which is predicted to be strongly influenced by a plant's proportional allocation to leaves, is a major determinant of the transient dynamics of competition. These dynamics may explain the differences between successions on poor versus rich soils and suggest that most field experiments performed to date have been of too short a duration to allow unambiguous interpretation of their results.",
    url = "https://doi.org/10.5860/choice.26-0924",
    doi = "10.5860/choice.26-0924",
    openalex = "W1488595547"
}

We present a quantitative literature review to assess the extent to which field experiments with plants have addressed questions about patterns of competition over time and space, consequences of competition for community structure, and comparisons of competitive ability among species. We outline the necessary treatment comparisons and statistical analyses to answer each question and then describe the number of experiments that meet these criteria and their results. Although we found a total of 101 experiments in 89 studies, 63% of these experiments only addressed whether competition significantly affected some component of individual fitness of a single species at a single time and site. Despite the limited data base to address more complex questions about competitive interactions, we did find consistent results for a few of the questions we reviewed. Where tested, competition always had significant effects on distribution patterns (five experiments), on relative abundances (two experiments), and on diversity (four experiments), consistent with the notion that competition has strong effects on community structure. On the other hand, intraspecific competition was not usually stronger than interspecific competition for either competitive effect (four experiments) or response (three experiments), which suggests that resource partitioning may not be an important mechanism of coexistence in plants.

@article{doi101086285357,
    author = "Goldberg, Deborah E. and Barton, Andrew M.",
    title = "Patterns and Consequences of Interspecific Competition in Natural Communities: A Review of Field Experiments with Plants",
    year = "1992",
    journal = "The American Naturalist",
    abstract = "We present a quantitative literature review to assess the extent to which field experiments with plants have addressed questions about patterns of competition over time and space, consequences of competition for community structure, and comparisons of competitive ability among species. We outline the necessary treatment comparisons and statistical analyses to answer each question and then describe the number of experiments that meet these criteria and their results. Although we found a total of 101 experiments in 89 studies, 63\% of these experiments only addressed whether competition significantly affected some component of individual fitness of a single species at a single time and site. Despite the limited data base to address more complex questions about competitive interactions, we did find consistent results for a few of the questions we reviewed. Where tested, competition always had significant effects on distribution patterns (five experiments), on relative abundances (two experiments), and on diversity (four experiments), consistent with the notion that competition has strong effects on community structure. On the other hand, intraspecific competition was not usually stronger than interspecific competition for either competitive effect (four experiments) or response (three experiments), which suggests that resource partitioning may not be an important mechanism of coexistence in plants.",
    url = "https://doi.org/10.1086/285357",
    doi = "10.1086/285357",
    openalex = "W2136035194",
    references = "doi101086282697, doi101086283244, doi101086283366, doi101111j1469185x1977tb01347x, doi101126science2304728895, doi1015159781400881376, doi1023071942661, doi1023074549, openalexw2077454220, openalexw2169917233"
}

All organisms, especially terrestrial plants and other sessile species, interact mainly with their neighbors, but neighborhoods can differ in composition because of dispersal and mortality. There is increasingly strong evidence that the spatial structure created by these forces profoundly influences the dynamics, composition, and biodiversity of communities. Nonspatial models predict that no more consumer species can coexist at equilibrium than there are limiting resources. In contrast, a similar model that includes neighborhood competition and random dispersal among sites predicts stable coexistence of a potentially unlimited number of species on a single resource. Coexistence occurs because species with sufficiently high dispersal rates persist in sites not occupied by superior competitors. Coexistence requires limiting similarity and two—way or three—way interspecific trade—offs among competitive ability, colonization ability, and longevity. This spatial competition hypothesis seems to explain the coexistence of the numerous plant species that compete for a single limiting resource in the grasslands of Cedar Creek Natural History Area. It provides a testable, alternative explanation for other high diversity communities, such as tropical forests. The model can be tested (1) by determining if coexisting species have the requisite trade—offs in colonization, competition, and longevity, (2) by addition of propagules of propagules to determine if local species abundances are limited by dispersal, and (3) by comparisons of the effects on biodiversity of high rates of propagule addition for species that differ in competitive ability.

@article{doi1023071939377,
    author = "Tilman, David",
    title = "Competition and Biodiversity in Spatially Structured Habitats",
    year = "1994",
    journal = "Ecology",
    abstract = "All organisms, especially terrestrial plants and other sessile species, interact mainly with their neighbors, but neighborhoods can differ in composition because of dispersal and mortality. There is increasingly strong evidence that the spatial structure created by these forces profoundly influences the dynamics, composition, and biodiversity of communities. Nonspatial models predict that no more consumer species can coexist at equilibrium than there are limiting resources. In contrast, a similar model that includes neighborhood competition and random dispersal among sites predicts stable coexistence of a potentially unlimited number of species on a single resource. Coexistence occurs because species with sufficiently high dispersal rates persist in sites not occupied by superior competitors. Coexistence requires limiting similarity and two—way or three—way interspecific trade—offs among competitive ability, colonization ability, and longevity. This spatial competition hypothesis seems to explain the coexistence of the numerous plant species that compete for a single limiting resource in the grasslands of Cedar Creek Natural History Area. It provides a testable, alternative explanation for other high diversity communities, such as tropical forests. The model can be tested (1) by determining if coexisting species have the requisite trade—offs in colonization, competition, and longevity, (2) by addition of propagules of propagules to determine if local species abundances are limited by dispersal, and (3) by comparisons of the effects on biodiversity of high rates of propagule addition for species that differ in competitive ability.",
    url = "https://doi.org/10.2307/1939377",
    doi = "10.2307/1939377",
    openalex = "W2159641034",
    references = "doi101038359826a0, doi101086282687, doi101086283366, doi101093besa153237, doi101093biomet3812196, doi101111j1469185x1977tb01347x, doi101126science20343871299, doi101146annureves11110180001313, doi1015159780691206912, doi1015159781400881376, doi1023073544021, doi1023075503, openalexw1612551514"
}

This review reevaluates the importance of interspecific competition in the population biology of phytophagous insects and assesses factors that mediate competition. An examination of 193 pair-wise species interactions, repre­ senting all major feeding guilds, provided information on the occurrence, frequency, symmetry, consequences, and mechanisms of competition. Inter­ specific competition occurred in 76% of interactions, was often asymmetric, and was frequent in most guil ds (sap feeders, wood and stem borers, seed and fruit feeders) except free-living mandibulate folivores. Phytophagous insects were more likely to compete if they were closely related, introduced, sessile, aggregative, fed on discrete resources, and fed on forbs or grasses. Interference 297 0066-4170/95/0101-0297$05.00 A nn u. R ev. E nt om ol. 1 99 5. 40:2 97 -3 31. D ow nl oa de d fr om w w w.a nn ua lr ev ie w s. or g by T ex as S ta te U ni ve rs ity S an M ar co s on 0 5/ 16 /1 3. F or p er so na l u se o nl y. 298 DENNO, McCLURE & OTT competition was most frequent between mandibulate herbivores living in con­ cealed niches. Host plants mediated competitive interactions more frequently than natural enemies, physical factors, and interspecific competition. Sufficient experimental evidence exists to reinstate interspecific competition as a viable hypothesis warranting serious consideration in future investigations of the structure of phytophagous insect communities.

@article{doi101146annureven40010195001501,
    author = "Denno, Robert F. and McClure, M. S. and Ott, James R.",
    title = "Interspecific Interactions in Phytophagous Insects: Competition Reexamined and Resurrected",
    year = "1995",
    journal = "Annual Review of Entomology",
    abstract = "This review reevaluates the importance of interspecific competition in the population biology of phytophagous insects and assesses factors that mediate competition. An examination of 193 pair-wise species interactions, repre­ senting all major feeding guilds, provided information on the occurrence, frequency, symmetry, consequences, and mechanisms of competition. Inter­ specific competition occurred in 76\% of interactions, was often asymmetric, and was frequent in most guil ds (sap feeders, wood and stem borers, seed and fruit feeders) except free-living mandibulate folivores. Phytophagous insects were more likely to compete if they were closely related, introduced, sessile, aggregative, fed on discrete resources, and fed on forbs or grasses. Interference 297 0066-4170/95/0101-0297$05.00 A nn u. R ev. E nt om ol. 1 99 5. 40:2 97 -3 31. D ow nl oa de d fr om w w w.a nn ua lr ev ie w s. or g by T ex as S ta te U ni ve rs ity S an M ar co s on 0 5/ 16 /1 3. F or p er so na l u se o nl y. 298 DENNO, McCLURE \& OTT competition was most frequent between mandibulate herbivores living in con­ cealed niches. Host plants mediated competitive interactions more frequently than natural enemies, physical factors, and interspecific competition. Sufficient experimental evidence exists to reinstate interspecific competition as a viable hypothesis warranting serious consideration in future investigations of the structure of phytophagous insect communities.",
    url = "https://doi.org/10.1146/annurev.en.40.010195.001501",
    doi = "10.1146/annurev.en.40.010195.001501",
    openalex = "W2175489184",
    references = "doi101007bf00378812, doi101093aesa812245, doi101111j109583121988tb00472x, doi101139z78250"
}

Belowground competition occurs when plants decrease the growth, survival, or fecundity of neighbors by reducing available soil resources. Competition belowground can be stronger and involve many more neighbors than aboveground competition. Physiological ecologists and population or community ecologists have traditionally studied belowground competition from different perspectives. Physiologically based studies often measure resource uptake without determining the integrated consequences for plant performance, while population or community level studies examine plant performance but fail to identify the resource intermediary or mechanism. Belowground competitive ability is correlated with such attributes as root density, surface area, and plasticity either in root growth or in the properties of enzymes involved in nutrient uptake. Unlike competition for light, in which larger plants have a disproportionate advantage by shading smaller ones, competition for soil resources is apparently more symmetric. Belowground competition often decreases with increases in nutrient levels, but it is premature to generalize about the relative importance of above- and belowground competition across resource gradients. Although shoot and root competition are often assumed to have additive effects on plant growth, some studies provide evidence to the contrary, and potential interactions between the two forms of competition should be considered in future investigations. Other research recommendations include the simultaneous study of root and shoot gaps, since their closures may not occur simultaneously, and improved estimates of the belowground neighborhood. Only by combining the tools and perspectives from physiological ecology and population and community biology can we fully understand how soil characteristics, neighborhood structure, and global climate change influence or are influenced by plant competition belowground.

@article{doi101146annurevecolsys281545,
    author = "Casper, Brenda B. and Jackson, Robert B.",
    title = "Plant Competition Underground",
    year = "1997",
    journal = "Annual Review of Ecology and Systematics",
    abstract = "Belowground competition occurs when plants decrease the growth, survival, or fecundity of neighbors by reducing available soil resources. Competition belowground can be stronger and involve many more neighbors than aboveground competition. Physiological ecologists and population or community ecologists have traditionally studied belowground competition from different perspectives. Physiologically based studies often measure resource uptake without determining the integrated consequences for plant performance, while population or community level studies examine plant performance but fail to identify the resource intermediary or mechanism. Belowground competitive ability is correlated with such attributes as root density, surface area, and plasticity either in root growth or in the properties of enzymes involved in nutrient uptake. Unlike competition for light, in which larger plants have a disproportionate advantage by shading smaller ones, competition for soil resources is apparently more symmetric. Belowground competition often decreases with increases in nutrient levels, but it is premature to generalize about the relative importance of above- and belowground competition across resource gradients. Although shoot and root competition are often assumed to have additive effects on plant growth, some studies provide evidence to the contrary, and potential interactions between the two forms of competition should be considered in future investigations. Other research recommendations include the simultaneous study of root and shoot gaps, since their closures may not occur simultaneously, and improved estimates of the belowground neighborhood. Only by combining the tools and perspectives from physiological ecology and population and community biology can we fully understand how soil characteristics, neighborhood structure, and global climate change influence or are influenced by plant competition belowground.",
    url = "https://doi.org/10.1146/annurev.ecolsys.28.1.545",
    doi = "10.1146/annurev.ecolsys.28.1.545",
    openalex = "W2138626896",
    references = "doi101007bf02912621, doi1023072937039"
}

Interactions among organisms take place within a complex milieu of abiotic and biotic processes, but we generally study them as solitary phenomena. Complex combinations of negative and positive interactions have been identified in a number of plant communities. The importance of these two processes in structuring plant communities can best be understood by comparing them along gradients of abiotic stress, consumer pressure, and among different life stages, sizes, and densities of the interacting species. Here, we discuss the roles of life stage, physiology, indirect interactions, and the physical environment on the balance of competition and facilitation in plant communities.

@article{doi1018900012965819970781958cafasa20co2,
    author = "Callaway, Ragan M. and Walker, Lawrence R.",
    title = "COMPETITION AND FACILITATION: A SYNTHETIC APPROACH TO INTERACTIONS IN PLANT COMMUNITIES",
    year = "1997",
    journal = "Ecology",
    abstract = "Interactions among organisms take place within a complex milieu of abiotic and biotic processes, but we generally study them as solitary phenomena. Complex combinations of negative and positive interactions have been identified in a number of plant communities. The importance of these two processes in structuring plant communities can best be understood by comparing them along gradients of abiotic stress, consumer pressure, and among different life stages, sizes, and densities of the interacting species. Here, we discuss the roles of life stage, physiology, indirect interactions, and the physical environment on the balance of competition and facilitation in plant communities.",
    url = "https://doi.org/10.1890/0012-9658(1997)078[1958:cafasa]2.0.co;2",
    doi = "10.1890/0012-9658(1997)078[1958:cafasa]2.0.co;2",
    openalex = "W2084253034",
    references = "doi101007bf02912621, doi1010160169534794900884, doi101086283241, doi101086284133, doi101086284165, doi101086285357, doi1018900012965819970781966tiofac20co2, doi1023072937039, doi105860choice260924, doi105860choice330294, doi105962bhltitle56234, openalexw2169917233"
}

If plants cannot simultaneously acclimate to shade and drought because of physiological trade-offs, then plants are expected to be less tolerant to shading under drier conditions. One observation that, at first sight, seems incompatible with this idea is the fact that the establishment of new plants in dry areas is often restricted to shady sites under the canopy of other plants, called "nurse plants." We use a graphical model to resolve this paradox. The model visualizes how facilitative patterns can be understood from the simultaneous effects of plant canopies on microsite light and moisture, and the growth responses of establishing seedlings to those factors. The approach emphasizes the fact that positive and negative effects of plant canopies always occur simultaneously. In the presented light–water model, facilitation only occurs when the improvement of plant water relations under the canopy exceeds the costs caused by lower light levels. This may be true under dry conditions, whereas in less dry situations, competition rather than facilitation is observed. The model shows how changes in water availability may shift interactions from competitive to facilitative and vice versa, as observed in some field patterns. It is argued that other environmental factors explaining facilitative patterns can be understood in the same context.

@article{doi1018900012965819970781966tiofac20co2,
    author = "Holmgren, Milena and Scheffer, Marten and Huston, Michael A.",
    title = "THE INTERPLAY OF FACILITATION AND COMPETITION IN PLANT COMMUNITIES",
    year = "1997",
    journal = "Ecology",
    abstract = {If plants cannot simultaneously acclimate to shade and drought because of physiological trade-offs, then plants are expected to be less tolerant to shading under drier conditions. One observation that, at first sight, seems incompatible with this idea is the fact that the establishment of new plants in dry areas is often restricted to shady sites under the canopy of other plants, called "nurse plants." We use a graphical model to resolve this paradox. The model visualizes how facilitative patterns can be understood from the simultaneous effects of plant canopies on microsite light and moisture, and the growth responses of establishing seedlings to those factors. The approach emphasizes the fact that positive and negative effects of plant canopies always occur simultaneously. In the presented light–water model, facilitation only occurs when the improvement of plant water relations under the canopy exceeds the costs caused by lower light levels. This may be true under dry conditions, whereas in less dry situations, competition rather than facilitation is observed. The model shows how changes in water availability may shift interactions from competitive to facilitative and vice versa, as observed in some field patterns. It is argued that other environmental factors explaining facilitative patterns can be understood in the same context.},
    url = "https://doi.org/10.1890/0012-9658(1997)078[1966:tiofac]2.0.co;2",
    doi = "10.1890/0012-9658(1997)078[1966:tiofac]2.0.co;2",
    openalex = "W2088443113",
    references = "doi1010079783322865823, doi1010079783642809132, doi1010079783642965456, doi101007bf02912621, doi1010160169534794900884, doi101086283241, doi101086284133, doi101086284165, doi101086285357, doi101146annureves16110185002051, doi105860choice260924"
}

Because of the correlation expected between the phylogenetic relatedness of two taxa and their net ecological similarity, a measure of the overall phylogenetic relatedness of a community of interacting organisms can be used to investigate the contemporary ecological processes that structure community composition. I describe two indices that use the number of nodes that separate taxa on a phylogeny as a measure of their phylogenetic relatedness. As an example of the use of these indices in community analysis, I compared the mean observed net relatedness of trees (≥10 cm diameter at breast height) in each of 28 plots (each 0.16 ha) in a Bornean rain forest with the net relatedness expected if species were drawn randomly from the species pool (of the 324 species in the 28 plots), using a supertree that I assembled from published sources. I found that the species in plots were more phylogenetically related than expected by chance, a result that was insensitive to various modifications to the basic methodology. I tentatively infer that variation in habitat among plots causes ecologically more similar species to co-occur within plots. Finally, I suggest a range of applications for phylogenetic relatedness measures in community analysis.

@article{doi101086303378,
    author = "Webb, Campbell O.",
    title = "Exploring the Phylogenetic Structure of Ecological Communities: An Example for Rain Forest Trees",
    year = "2000",
    journal = "The American Naturalist",
    abstract = "Because of the correlation expected between the phylogenetic relatedness of two taxa and their net ecological similarity, a measure of the overall phylogenetic relatedness of a community of interacting organisms can be used to investigate the contemporary ecological processes that structure community composition. I describe two indices that use the number of nodes that separate taxa on a phylogeny as a measure of their phylogenetic relatedness. As an example of the use of these indices in community analysis, I compared the mean observed net relatedness of trees (≥10 cm diameter at breast height) in each of 28 plots (each 0.16 ha) in a Bornean rain forest with the net relatedness expected if species were drawn randomly from the species pool (of the 324 species in the 28 plots), using a supertree that I assembled from published sources. I found that the species in plots were more phylogenetically related than expected by chance, a result that was insensitive to various modifications to the basic methodology. I tentatively infer that variation in habitat among plots causes ecologically more similar species to co-occur within plots. Finally, I suggest a range of applications for phylogenetic relatedness measures in community analysis.",
    url = "https://doi.org/10.1086/303378",
    doi = "10.1086/303378",
    openalex = "W2057819145",
    references = "doi101126science20343871299, doi1015159781400860180203, doi1023071446122, doi1023072399846, doi102307jctt1xp3v3r, doi105860choice392183"
}

@article{doi1016410006356820010510235mfatso20co2,
    author = "Stachowicz, John J.",
    title = "Mutualism, Facilitation, and the Structure of Ecological Communities",
    year = "2001",
    journal = "BioScience",
    url = "https://doi.org/10.1641/0006-3568(2001)051[0235:mfatso]2.0.co;2",
    doi = "10.1641/0006-3568(2001)051[0235:mfatso]2.0.co;2",
    openalex = "W2259349023",
    references = "doi101002iroh19700550103, doi101007bf02912621, doi1018900012965819970781958cafasa20co2, doi1023071936969, doi1023071942565"
}

This review discusses the interface between two of the most important types of interactions between species, interspecific competition and predation. Predation has been claimed to increase, decrease, or have little effect on, the strength, impact or importance of interspecific competition. There is confusion about both the meaning of these terms and the likelihood of, and conditions required for, each of these outcomes. In this article we distinguish among three measures of the influence of predation on competitive outcomes: short‐term per capita consumption or growth rates, long‐term changes in density, and the probability of competitive coexistence. We then outline various theoretical mechanisms that can lead to qualitatively distinct effects of predators. The qualitative effect of predators can depend both on the mechanism of competition and on the definition of competitive strength/impact. In assessing the empirical literature, we ask: (1) What definitions of competitive strength/impact have been assumed? (2) Does strong evidence exist to support one or more of the possible mechanisms that can produce a given outcome? (3) Do biases in the choice of organism or manipulation exist, and are they likely to have influenced the conclusions reached? We conclude by discussing several unanswered questions, and espouse a stronger interchange between empirical and theoretical approaches to this important question.

@article{doi101046j14610248200200315x,
    author = "Chase, Jonathan M. and Abrams, Peter A. and Grover, James P. and Diehl, Sebastian and Chesson, Peter and Holt, Robert D. and Richards, Shane A. and Nisbet, Roger M. and Case, Ted J.",
    title = "The interaction between predation and competition: a review and synthesis",
    year = "2002",
    journal = "Ecology Letters",
    abstract = "This review discusses the interface between two of the most important types of interactions between species, interspecific competition and predation. Predation has been claimed to increase, decrease, or have little effect on, the strength, impact or importance of interspecific competition. There is confusion about both the meaning of these terms and the likelihood of, and conditions required for, each of these outcomes. In this article we distinguish among three measures of the influence of predation on competitive outcomes: short‐term per capita consumption or growth rates, long‐term changes in density, and the probability of competitive coexistence. We then outline various theoretical mechanisms that can lead to qualitatively distinct effects of predators. The qualitative effect of predators can depend both on the mechanism of competition and on the definition of competitive strength/impact. In assessing the empirical literature, we ask: (1) What definitions of competitive strength/impact have been assumed? (2) Does strong evidence exist to support one or more of the possible mechanisms that can produce a given outcome? (3) Do biases in the choice of organism or manipulation exist, and are they likely to have influenced the conclusions reached? We conclude by discussing several unanswered questions, and espouse a stronger interchange between empirical and theoretical approaches to this important question.",
    url = "https://doi.org/10.1046/j.1461-0248.2002.00315.x",
    doi = "10.1046/j.1461-0248.2002.00315.x",
    openalex = "W2116100176",
    references = "doi101146annureven40010195001501, openalexw2045291252"
}

▪ Abstract As better phylogenetic hypotheses become available for many groups of organisms, studies in community ecology can be informed by knowledge of the evolutionary relationships among coexisting species. We note three primary approaches to integrating phylogenetic information into studies of community organization: 1. examining the phylogenetic structure of community assemblages, 2. exploring the phylogenetic basis of community niche structure, and 3. adding a community context to studies of trait evolution and biogeography. We recognize a common pattern of phylogenetic conservatism in ecological character and highlight the challenges of using phylogenies of partial lineages. We also review phylogenetic approaches to three emergent properties of communities: species diversity, relative abundance distributions, and range sizes. Methodological advances in phylogenetic supertree construction, character reconstruction, null models for community assembly and character evolution, and metrics of community phylogenetic structure underlie the recent progress in these areas. We highlight the potential for community ecologists to benefit from phylogenetic knowledge and suggest several avenues for future research.

@article{doi101146annurevecolsys33010802150448,
    author = "Webb, Campbell O. and Ackerly, David D. and McPeek, Mark A. and Donoghue, Michael J.",
    title = "Phylogenies and Community Ecology",
    year = "2002",
    journal = "Annual Review of Ecology and Systematics",
    abstract = "▪ Abstract As better phylogenetic hypotheses become available for many groups of organisms, studies in community ecology can be informed by knowledge of the evolutionary relationships among coexisting species. We note three primary approaches to integrating phylogenetic information into studies of community organization: 1. examining the phylogenetic structure of community assemblages, 2. exploring the phylogenetic basis of community niche structure, and 3. adding a community context to studies of trait evolution and biogeography. We recognize a common pattern of phylogenetic conservatism in ecological character and highlight the challenges of using phylogenies of partial lineages. We also review phylogenetic approaches to three emergent properties of communities: species diversity, relative abundance distributions, and range sizes. Methodological advances in phylogenetic supertree construction, character reconstruction, null models for community assembly and character evolution, and metrics of community phylogenetic structure underlie the recent progress in these areas. We highlight the potential for community ecologists to benefit from phylogenetic knowledge and suggest several avenues for future research.",
    url = "https://doi.org/10.1146/annurev.ecolsys.33.010802.150448",
    doi = "10.1146/annurev.ecolsys.33.010802.150448",
    openalex = "W2109628725",
    references = "doi10100797814615696881, doi101007978303487527124, doi101007bf02806171, doi101016s0169534701021619, doi101038363342a0, doi10108010292389509380518, doi101086282106, doi101086282505, doi101086284325, doi101086285258, doi101086285357, doi101086627905, doi101093oso97801985052350010001, doi101093oso97801985464120010001, doi101093oxfordjournalsmolbeva003974, doi101093oxfordjournalsmolbeva025892, doi101098rstb19950125, doi101111j001438202001tb00826x, doi101111j109583122001tb01368x, doi101126science20343871299, doi101126science2354785167, doi101126science2785338692, doi101126science27953592115, doi101126science28554311265, doi101146annurevecolsys311343, doi1015159781400881376, doi1023071446122, doi1023071939377, doi1023072412182, doi1023072413039, doi1023072485224, doi1023073071998, doi1023073544421, doi1023075503, doi102307jctv1nzfgj7, doi105860choice295104, doi105860choice375647, doi105860choice392183, openalexw2273605253, openalexw3035987306"
}

Competitive displacement is the most severe outcome of interspecific competition. For the purposes of this review, we define this type of displacement as the removal of a formerly established species from a habitat as a result of direct or indirect competitive interactions with another species. We reviewed the literature for recent putative cases of competitive displacement among insects and arachnids and assessed the evidence for the role of interspecific competition in these displacements. We found evidence for mechanisms of both exploitation and interference competition operating in these cases of competitive displacement. Many of the cases that we identified involve the operation of more than one competitive mechanism, and many cases were mediated by other noncompetitive factors. Most, but not all, of these displacements occurred between closely related species. In the majority of cases, exotic species displaced native species or previously established exotic species, often in anthropogenically-altered habitats. The cases that we identified have occurred across a broad range of taxa and environments. Therefore we suggest that competitive displacement has the potential to be a widespread phenomenon, and the frequency of these displacement events may increase, given the ever-increasing degree of anthropogenic changes to the environment. A greater awareness of competitive displacement events should lead to more studies documenting the relative importance of key factors and developing hypotheses that explain observed patterns.

@article{doi101146annurevento47091201145227,
    author = "Reitz, Stuart R. and Trumble, John T.",
    title = "Competitive Displacement Among Insects and Arachnids",
    year = "2002",
    journal = "Annual Review of Entomology",
    abstract = "Competitive displacement is the most severe outcome of interspecific competition. For the purposes of this review, we define this type of displacement as the removal of a formerly established species from a habitat as a result of direct or indirect competitive interactions with another species. We reviewed the literature for recent putative cases of competitive displacement among insects and arachnids and assessed the evidence for the role of interspecific competition in these displacements. We found evidence for mechanisms of both exploitation and interference competition operating in these cases of competitive displacement. Many of the cases that we identified involve the operation of more than one competitive mechanism, and many cases were mediated by other noncompetitive factors. Most, but not all, of these displacements occurred between closely related species. In the majority of cases, exotic species displaced native species or previously established exotic species, often in anthropogenically-altered habitats. The cases that we identified have occurred across a broad range of taxa and environments. Therefore we suggest that competitive displacement has the potential to be a widespread phenomenon, and the frequency of these displacement events may increase, given the ever-increasing degree of anthropogenic changes to the environment. A greater awareness of competitive displacement events should lead to more studies documenting the relative importance of key factors and developing hypotheses that explain observed patterns.",
    url = "https://doi.org/10.1146/annurev.ento.47.091201.145227",
    doi = "10.1146/annurev.ento.47.091201.145227",
    openalex = "W2116999903",
    references = "doi101146annureven40010195001501"
}

Stochastic niche theory resolves many of the differences between neutral theory and classical tradeoff-based niche theories of resource competition and community structure. In stochastic niche theory, invading species become established only if propagules can survive stochastic mortality while growing to maturity on the resources left unconsumed by established species. The theory makes three predictions about community structure. First, stochastic niche assembly creates communities in which species dominate approximately equally wide "slices" of the habitat's spatial heterogeneity. These niche widths generate realistic distributions of species relative abundances for which, contrary to neutral theory but consistent with numerous observations, there are strong correlations among species traits, species abundances, and environmental conditions. Second, slight decreases in resource levels are predicted to cause large decreases in the probability that a propagule would survive to be an adult. These decreases cause local diversity to be limited by the inhibitory effects of resource use by established species on the establishment (recruitment) of potential invaders. If resource pulses or disturbance allowed invaders to overcome this recruitment limitation, many more species could indefinitely coexist. Third, the low invasibility of high diversity communities is predicted to result not from diversity per se, but from the uniformly low levels of resources that occur in high-diversity communities created by stochastic competitive assembly. This prediction provides a potential solution to the invasion paradox, which is the tendency for highly diverse regions to be more heavily invaded.

@article{doi101073pnas0403458101,
    author = "Tilman, David",
    title = "Niche tradeoffs, neutrality, and community structure: A stochastic theory of resource competition, invasion, and community assembly",
    year = "2004",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = {Stochastic niche theory resolves many of the differences between neutral theory and classical tradeoff-based niche theories of resource competition and community structure. In stochastic niche theory, invading species become established only if propagules can survive stochastic mortality while growing to maturity on the resources left unconsumed by established species. The theory makes three predictions about community structure. First, stochastic niche assembly creates communities in which species dominate approximately equally wide "slices" of the habitat's spatial heterogeneity. These niche widths generate realistic distributions of species relative abundances for which, contrary to neutral theory but consistent with numerous observations, there are strong correlations among species traits, species abundances, and environmental conditions. Second, slight decreases in resource levels are predicted to cause large decreases in the probability that a propagule would survive to be an adult. These decreases cause local diversity to be limited by the inhibitory effects of resource use by established species on the establishment (recruitment) of potential invaders. If resource pulses or disturbance allowed invaders to overcome this recruitment limitation, many more species could indefinitely coexist. Third, the low invasibility of high diversity communities is predicted to result not from diversity per se, but from the uniformly low levels of resources that occur in high-diversity communities created by stochastic competitive assembly. This prediction provides a potential solution to the invasion paradox, which is the tendency for highly diverse regions to be more heavily invaded.},
    url = "https://doi.org/10.1073/pnas.0403458101",
    doi = "10.1073/pnas.0403458101",
    openalex = "W2169175623",
    references = "doi1010160040580970900390, doi101073pnas6951109, doi1023071939377"
}

Naturally occurring populations of bacteria and archaea are vital to life on the earth and are of enormous practical significance in medicine, engineering and agriculture. However, the rules governing the formation of such communities are still poorly understood, and there is a need for a usable mathematical description of this process. Typically, microbial community structure is thought to be shaped mainly by deterministic factors such as competition and niche differentiation. Here we show, for a wide range of prokaryotic communities, that the relative abundance and frequency with which different taxa are observed in samples can be explained by a neutral community model (NCM). The NCM, which is a stochastic, birth-death immigration process, does not explicitly represent the deterministic factors and therefore cannot be a complete or literal description of community assembly. However, its success suggests that chance and immigration are important forces in shaping the patterns seen in prokaryotic communities.

@article{doi101111j14622920200500956x,
    author = "Sloan, William T. and Lunn, Mary and Woodcock, Stephen and Head, Ian M. and Nee, Sean and Curtis, Thomas P.",
    title = "Quantifying the roles of immigration and chance in shaping prokaryote community structure",
    year = "2005",
    journal = "Environmental Microbiology",
    abstract = "Naturally occurring populations of bacteria and archaea are vital to life on the earth and are of enormous practical significance in medicine, engineering and agriculture. However, the rules governing the formation of such communities are still poorly understood, and there is a need for a usable mathematical description of this process. Typically, microbial community structure is thought to be shaped mainly by deterministic factors such as competition and niche differentiation. Here we show, for a wide range of prokaryotic communities, that the relative abundance and frequency with which different taxa are observed in samples can be explained by a neutral community model (NCM). The NCM, which is a stochastic, birth-death immigration process, does not explicitly represent the deterministic factors and therefore cannot be a complete or literal description of community assembly. However, its success suggests that chance and immigration are important forces in shaping the patterns seen in prokaryotic communities.",
    url = "https://doi.org/10.1111/j.1462-2920.2005.00956.x",
    doi = "10.1111/j.1462-2920.2005.00956.x",
    openalex = "W2068381362",
    references = "doi1023071939377"
}

This paper considers key issues in plant invasion ecology, where findings published since 1990 have significantly improved our understanding of many aspects of invasions. The review focuses on vascular plants invading natural and semi-natural ecosystems, and on fundamental ecological issues relating to species invasiveness and community invasibility. Three big questions addressed by the SCOPE programme in the 1980s (which species invade; which habitats are invaded; and how can we manage invasions?) still underpin most work in invasion ecology. Some organizing and unifying themes in the field are organism-focused and relate to species invasiveness (the tens rule; the concept of residence time; taxonomic patterns and Darwin’s naturalization hypothesis; issues of phenotypic plasticity and rapid evolutionary change, including evolution of increased competitive ability hypothesis; the role of long-distance dispersal). Others are ecosystem-centred and deal with determinants of the invasibility of communities, habitats and regions (levels of invasion, invasibility and propagule pressure; the biotic resistance hypothesis and the links between diversity and invasibility; synergisms, mutualisms, and invasional meltdown). Some theories have taken an overarching approach to plant invasions by integrating the concepts of species invasiveness and community invasibility (a theory of seed plant invasiveness; fluctuating resources theory of invasibility). Concepts, hypotheses and theories reviewed here can be linked to the naturalization-invasion continuum concept, which relates invasion processes with a sequence of environmental and biotic barriers that an introduced species must negotiate to become casual, naturalized and invasive. New research tools and improved research links between invasion ecology and succession ecology, community ecology, conservation biology and weed science, respectively, have strengthened the conceptual pillars of invasion ecology.

@article{doi1011910309133306pp490pr,
    author = "Richardson, David M. and Pyšek, Petr",
    title = "Plant invasions: merging the concepts of species invasiveness and community invasibility",
    year = "2006",
    journal = "Progress in Physical Geography Earth and Environment",
    abstract = "This paper considers key issues in plant invasion ecology, where findings published since 1990 have significantly improved our understanding of many aspects of invasions. The review focuses on vascular plants invading natural and semi-natural ecosystems, and on fundamental ecological issues relating to species invasiveness and community invasibility. Three big questions addressed by the SCOPE programme in the 1980s (which species invade; which habitats are invaded; and how can we manage invasions?) still underpin most work in invasion ecology. Some organizing and unifying themes in the field are organism-focused and relate to species invasiveness (the tens rule; the concept of residence time; taxonomic patterns and Darwin’s naturalization hypothesis; issues of phenotypic plasticity and rapid evolutionary change, including evolution of increased competitive ability hypothesis; the role of long-distance dispersal). Others are ecosystem-centred and deal with determinants of the invasibility of communities, habitats and regions (levels of invasion, invasibility and propagule pressure; the biotic resistance hypothesis and the links between diversity and invasibility; synergisms, mutualisms, and invasional meltdown). Some theories have taken an overarching approach to plant invasions by integrating the concepts of species invasiveness and community invasibility (a theory of seed plant invasiveness; fluctuating resources theory of invasibility). Concepts, hypotheses and theories reviewed here can be linked to the naturalization-invasion continuum concept, which relates invasion processes with a sequence of environmental and biotic barriers that an introduced species must negotiate to become casual, naturalized and invasive. New research tools and improved research links between invasion ecology and succession ecology, community ecology, conservation biology and weed science, respectively, have strengthened the conceptual pillars of invasion ecology.",
    url = "https://doi.org/10.1191/0309133306pp490pr",
    doi = "10.1191/0309133306pp490pr",
    openalex = "W2099376388",
    references = "doi101007978146124018114, doi1010079781489972149, doi101016s0169534702000459, doi101016s0169534702024953, doi101016s0169534702025545, doi101046j13652745200000473x, doi101046j14724642200000083x, doi101093oso97801985464120010001, doi101111j14610248200400657x, doi101146annureves23110192000431, doi1023072257385, doi1023073545850, doi105860choice295104"
}

Historically, the biodiversity and composition of species in a locality was thought to be influenced primarily by deterministic factors. In such cases, species' niches create differential responses to environmental conditions and interspecific interactions, which combine to determine that locality's biodiversity and species composition. More recently, proponents of the neutral theory have placed a premium on how stochastic factors, such as birth, death, colonization, and extinction (termed "ecological drift") influence diversity and species composition in a locality independent of their niches. Here, I develop the hypothesis that the relative importance of stochastic ecological drift and/or priority effects depend on the harshness of the ecological filter in those habitats. I established long-term experimental ponds to explore the relative importance of community assembly history and drought on patterns of community compositional similarity among ponds that were otherwise similar in their environmental conditions. I show considerable site-to-site variation in pond community composition in the absence of drought that likely resulted from a combination of stochastic ecological drift and priority effects. However, in ponds that experienced drought, I found much higher similarity among communities that likely resulted from niche-selection filtering out species from the regional pool that could not tolerate such environmental harshness. These results implicate the critical role for understanding the processes of community assembly when examining patterns of biodiversity at different spatial scales.

@article{doi101073pnas0704350104,
    author = "Chase, Jonathan M.",
    title = "Drought mediates the importance of stochastic community assembly",
    year = "2007",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = {Historically, the biodiversity and composition of species in a locality was thought to be influenced primarily by deterministic factors. In such cases, species' niches create differential responses to environmental conditions and interspecific interactions, which combine to determine that locality's biodiversity and species composition. More recently, proponents of the neutral theory have placed a premium on how stochastic factors, such as birth, death, colonization, and extinction (termed "ecological drift") influence diversity and species composition in a locality independent of their niches. Here, I develop the hypothesis that the relative importance of stochastic ecological drift and/or priority effects depend on the harshness of the ecological filter in those habitats. I established long-term experimental ponds to explore the relative importance of community assembly history and drought on patterns of community compositional similarity among ponds that were otherwise similar in their environmental conditions. I show considerable site-to-site variation in pond community composition in the absence of drought that likely resulted from a combination of stochastic ecological drift and priority effects. However, in ponds that experienced drought, I found much higher similarity among communities that likely resulted from niche-selection filtering out species from the regional pool that could not tolerate such environmental harshness. These results implicate the critical role for understanding the processes of community assembly when examining patterns of biodiversity at different spatial scales.},
    url = "https://doi.org/10.1073/pnas.0704350104",
    doi = "10.1073/pnas.0704350104",
    openalex = "W2156151748",
    references = "doi101111j14610248200600996x, doi101126science1057969"
}

1 Once neglected, the role of facilitative interactions in plant communities has received considerable attention in the last two decades, and is now widely recognized. It is timely to consider the progress made by research in this field. 2 We review the development of plant facilitation research, focusing on the history of the field, the relationship between plant–plant interactions and environmental severity gradients, and attempts to integrate facilitation into mainstream ecological theory. We then consider future directions for facilitation research. 3 With respect to our fundamental understanding of plant facilitation, clarification of the relationship between interactions and environmental gradients is central for further progress, and necessitates the design and implementation of experiments that move beyond the clear limitations of previous studies. 4 There is substantial scope for exploring indirect facilitative effects in plant communities, including their impacts on diversity and evolution, and future studies should connect the degree of non-transitivity in plant competitive networks to community diversity and facilitative promotion of species coexistence, and explore how the role of indirect facilitation varies with environmental severity. 5 Certain ecological modelling approaches (e.g. individual-based modelling), although thus far largely neglected, provide highly useful tools for exploring these fundamental processes. 6 Evolutionary responses might result from facilitative interactions, and consideration of facilitation might lead to re-assessment of the evolution of plant growth forms. 7 Improved understanding of facilitation processes has direct relevance for the development of tools for ecosystem restoration, and for improving our understanding of the response of plant species and communities to environmental change drivers. 8 Attempts to apply our developing ecological knowledge would benefit from explicit recognition of the potential role of facilitative plant–plant interactions in the design and interpretation of studies from the fields of restoration and global change ecology. 9 Synthesis: Plant facilitation research provides new insights into classic ecological theory and pressing environmental issues. Awareness and understanding of facilitation should be part of the basic ecological knowledge of all plant ecologists.

@article{doi101111j13652745200701295x,
    author = "Brooker, Rob W. and Maestre, Fernando T. and Callaway, Ragan M. and Lortie, Christopher L. and Cavieres, Lohengrin A. and Künstler, Georges and Liancourt, Pierre and Tielbörger, Katja and Travis, Justin M. J. and Anthelme, Fabien and Armas, Cristina and Coll, Lluís and Corcket, Emmanuel and Delzon, Sylvain and Forey, Estelle and Kikvidze, Zaal and Olofsson, Johan and Pugnaire, Francisco I. and Quiroz, Constanza L. and Saccone, Patrick and Schiffers, Katja and Seifan, Merav and Touzard, Blaize and Michalet, Richard",
    title = "Facilitation in plant communities: the past, the present, and the future",
    year = "2007",
    journal = "Journal of Ecology",
    abstract = "1 Once neglected, the role of facilitative interactions in plant communities has received considerable attention in the last two decades, and is now widely recognized. It is timely to consider the progress made by research in this field. 2 We review the development of plant facilitation research, focusing on the history of the field, the relationship between plant–plant interactions and environmental severity gradients, and attempts to integrate facilitation into mainstream ecological theory. We then consider future directions for facilitation research. 3 With respect to our fundamental understanding of plant facilitation, clarification of the relationship between interactions and environmental gradients is central for further progress, and necessitates the design and implementation of experiments that move beyond the clear limitations of previous studies. 4 There is substantial scope for exploring indirect facilitative effects in plant communities, including their impacts on diversity and evolution, and future studies should connect the degree of non-transitivity in plant competitive networks to community diversity and facilitative promotion of species coexistence, and explore how the role of indirect facilitation varies with environmental severity. 5 Certain ecological modelling approaches (e.g. individual-based modelling), although thus far largely neglected, provide highly useful tools for exploring these fundamental processes. 6 Evolutionary responses might result from facilitative interactions, and consideration of facilitation might lead to re-assessment of the evolution of plant growth forms. 7 Improved understanding of facilitation processes has direct relevance for the development of tools for ecosystem restoration, and for improving our understanding of the response of plant species and communities to environmental change drivers. 8 Attempts to apply our developing ecological knowledge would benefit from explicit recognition of the potential role of facilitative plant–plant interactions in the design and interpretation of studies from the fields of restoration and global change ecology. 9 Synthesis: Plant facilitation research provides new insights into classic ecological theory and pressing environmental issues. Awareness and understanding of facilitation should be part of the basic ecological knowledge of all plant ecologists.",
    url = "https://doi.org/10.1111/j.1365-2745.2007.01295.x",
    doi = "10.1111/j.1365-2745.2007.01295.x",
    openalex = "W1986322390",
    references = "doi101007bf02912621, doi101016s0169534702000459, doi101023a1010086329619, doi101038nrg700, doi101111j13652745200501017x, doi101111j1466822x200600212x, doi1018900012965819970781958cafasa20co2, doi1018900012965819970781966tiofac20co2, doi1023071939337, doi1023072937039"
}

The importance of interspecific competition is a highly controversial and unresolved issue for community ecology in general, and for phytophagous insects in particular. Recent advancements, however, in our understanding of indirect (plant- and enemy-mediated) interactions challenge the historical paradigms of competition. Thus, in the context of this rapidly developing field, we re-evaluate the evidence for interspecific competition in phytophagous insects using a meta-analysis of published studies. Our analysis is specifically designed to test the assumptions underlying traditional competition theory, namely that competitive interactions are symmetrical, necessitate spatial and temporal co-occurrence, and increase in intensity as the density, phylogenetic similarity, and niche overlap of competing species increase. Despite finding frequent evidence for competition, we found very little evidence that plant-feeding insects conform to theoretical predictions for interspecific competition. Interactions were highly asymmetrical, similar in magnitude within vs. between feeding guilds (chewers vs. sap-feeders), and were unaffected by the quantity of resources removed (% defoliation). There was mixed support for the effects of phylogeny, spatial/temporal separation, and the relative strength of intra- vs. interspecific competition. Clearly, a new paradigm that accounts for indirect interactions and facilitation is required to describe how interspecific competition contributes to the organization of phytophagous insect communities, and perhaps to other plant and animal communities as well.

@article{doi101111j14610248200701093x,
    author = "Kaplan, Ian and Denno, Robert F.",
    title = "Interspecific interactions in phytophagous insects revisited: a quantitative assessment of competition theory",
    year = "2007",
    journal = "Ecology Letters",
    abstract = "The importance of interspecific competition is a highly controversial and unresolved issue for community ecology in general, and for phytophagous insects in particular. Recent advancements, however, in our understanding of indirect (plant- and enemy-mediated) interactions challenge the historical paradigms of competition. Thus, in the context of this rapidly developing field, we re-evaluate the evidence for interspecific competition in phytophagous insects using a meta-analysis of published studies. Our analysis is specifically designed to test the assumptions underlying traditional competition theory, namely that competitive interactions are symmetrical, necessitate spatial and temporal co-occurrence, and increase in intensity as the density, phylogenetic similarity, and niche overlap of competing species increase. Despite finding frequent evidence for competition, we found very little evidence that plant-feeding insects conform to theoretical predictions for interspecific competition. Interactions were highly asymmetrical, similar in magnitude within vs. between feeding guilds (chewers vs. sap-feeders), and were unaffected by the quantity of resources removed (\% defoliation). There was mixed support for the effects of phylogeny, spatial/temporal separation, and the relative strength of intra- vs. interspecific competition. Clearly, a new paradigm that accounts for indirect interactions and facilitation is required to describe how interspecific competition contributes to the organization of phytophagous insect communities, and perhaps to other plant and animal communities as well.",
    url = "https://doi.org/10.1111/j.1461-0248.2007.01093.x",
    doi = "10.1111/j.1461-0248.2007.01093.x",
    openalex = "W2137980122",
    references = "doi101038118558a0, doi101038119012b0, doi101111j13652427200601592x, doi101146annureven40010195001501"
}

Ecology seeks to explain species coexistence and its functional consequences, but experimental tests of mechanisms that simultaneously account for both processes are difficult. We used an experimental mycorrhizal plant system to test whether functional similarity among closely related species (phylogenetic conservatism) can drive community assembly and ecosystem functioning. Communities were constructed with the same number of fungal species, but after 1 year of growth, realized species richness was highest where the starting species were more distantly related to each other. Communities with high realized species richness also stimulated plant productivity more than those with low realized species richness. Our findings suggest that phylogenetic trait conservatism can promote coexistence because of reduced competition between distinct evolutionary lineages and enhance ecosystem function because of functional complementarity among those same lineages.

@article{doi101126science1143082,
    author = "Maherali, Hafiz and Klironomos, John N.",
    title = "Influence of Phylogeny on Fungal Community Assembly and Ecosystem Functioning",
    year = "2007",
    journal = "Science",
    abstract = "Ecology seeks to explain species coexistence and its functional consequences, but experimental tests of mechanisms that simultaneously account for both processes are difficult. We used an experimental mycorrhizal plant system to test whether functional similarity among closely related species (phylogenetic conservatism) can drive community assembly and ecosystem functioning. Communities were constructed with the same number of fungal species, but after 1 year of growth, realized species richness was highest where the starting species were more distantly related to each other. Communities with high realized species richness also stimulated plant productivity more than those with low realized species richness. Our findings suggest that phylogenetic trait conservatism can promote coexistence because of reduced competition between distinct evolutionary lineages and enhance ecosystem function because of functional complementarity among those same lineages.",
    url = "https://doi.org/10.1126/science.1143082",
    doi = "10.1126/science.1143082",
    openalex = "W2083050401",
    references = "doi101016jtree200409003"
}

The assessment of microbial diversity and distribution is a major concern in environmental microbiology. There are two general approaches for measuring community diversity: quantitative measures, which use the abundance of each taxon, and qualitative measures, which use only the presence/absence of data. Quantitative measures are ideally suited to revealing community differences that are due to changes in relative taxon abundance (e.g., when a particular set of taxa flourish because a limiting nutrient source becomes abundant). Qualitative measures are most informative when communities differ primarily by what can live in them (e.g., at high temperatures), in part because abundance information can obscure significant patterns of variation in which taxa are present. We illustrate these principles using two 16S rRNA-based surveys of microbial populations and two phylogenetic measures of community beta diversity: unweighted UniFrac, a qualitative measure, and weighted UniFrac, a new quantitative measure, which we have added to the UniFrac website (http://bmf.colorado.edu/unifrac). These studies considered the relative influences of mineral chemistry, temperature, and geography on microbial community composition in acidic thermal springs in Yellowstone National Park and the influences of obesity and kinship on microbial community composition in the mouse gut. We show that applying qualitative and quantitative measures to the same data set can lead to dramatically different conclusions about the main factors that structure microbial diversity and can provide insight into the nature of community differences. We also demonstrate that both weighted and unweighted UniFrac measurements are robust to the methods used to build the underlying phylogeny.

@article{doi101128aem0199606,
    author = "Lozupone, Catherine and Hamady, Micah and Kelley, Scott T. and Knight, Rob",
    title = "Quantitative and Qualitative β Diversity Measures Lead to Different Insights into Factors That Structure Microbial Communities",
    year = "2007",
    journal = "Applied and Environmental Microbiology",
    abstract = "The assessment of microbial diversity and distribution is a major concern in environmental microbiology. There are two general approaches for measuring community diversity: quantitative measures, which use the abundance of each taxon, and qualitative measures, which use only the presence/absence of data. Quantitative measures are ideally suited to revealing community differences that are due to changes in relative taxon abundance (e.g., when a particular set of taxa flourish because a limiting nutrient source becomes abundant). Qualitative measures are most informative when communities differ primarily by what can live in them (e.g., at high temperatures), in part because abundance information can obscure significant patterns of variation in which taxa are present. We illustrate these principles using two 16S rRNA-based surveys of microbial populations and two phylogenetic measures of community beta diversity: unweighted UniFrac, a qualitative measure, and weighted UniFrac, a new quantitative measure, which we have added to the UniFrac website (http://bmf.colorado.edu/unifrac). These studies considered the relative influences of mineral chemistry, temperature, and geography on microbial community composition in acidic thermal springs in Yellowstone National Park and the influences of obesity and kinship on microbial community composition in the mouse gut. We show that applying qualitative and quantitative measures to the same data set can lead to dramatically different conclusions about the main factors that structure microbial diversity and can provide insight into the nature of community differences. We also demonstrate that both weighted and unweighted UniFrac measurements are robust to the methods used to build the underlying phylogeny.",
    url = "https://doi.org/10.1128/aem.01996-06",
    doi = "10.1128/aem.01996-06",
    openalex = "W2145664556",
    references = "doi101038260204c0, doi101086321317, doi101093bioinformaticsbtg180, doi101146annurevecolsys33010802150448, doi1023071218190, doi105860choice421547, openalexw2032279931"
}

Open source at: http://phylodiversity.net/phylocom/.

@article{doi101093bioinformaticsbtn358,
    author = "Webb, Campbell O. and Ackerly, David D. and Kembel, Steven W.",
    title = "Phylocom: software for the analysis of phylogenetic community structure and trait evolution",
    year = "2008",
    journal = "Bioinformatics",
    abstract = "Open source at: http://phylodiversity.net/phylocom/.",
    url = "https://doi.org/10.1093/bioinformatics/btn358",
    doi = "10.1093/bioinformatics/btn358",
    openalex = "W2164035292",
    references = "doi101093sysbio41118, doi101111j001438202003tb00285x, doi101111j14718286200400829x"
}

Summary The stress‐gradient hypothesis (SGH) predicts that the frequency of facilitative and competitive interactions will vary inversely across abiotic stress gradients, with facilitation being more common in conditions of high abiotic stress relative to more benign abiotic conditions. With notable exceptions, most tests of the SGH have studied the interaction between a single pair or a few pairs of species, and thus have evaluated shifts in the magnitude and direction of pair‐wise interactions along stress gradients, rather than shifts in the general frequency of interactions. The SGH has been supported by numerous studies in many ecosystems, has provided a crucial foundation for studying the interplay between facilitation and competition in plant communities, and has a high heuristic value. However, recent empirical research indicates that factors like the variation among species and the nature of the stress gradient studied add complexity not considered in the SGH, creating an opportunity to extend the SGH's general conceptual framework. We suggest that one approach for extending the SGH framework is to differentiate between the original idea of how ‘common’ interactions might be along stress gradients and the ubiquitous empirical approach of studying shifts in the strength of pair‐wise interactions. Furthermore, by explicitly considering the life history of the interacting species (relative tolerance to stress vs. competitive ability) and the characteristics of the stress factor (resource vs. non‐resource) we may be able to greatly refine specific predictions relevant to the SGH. We propose that the general pattern predicted by the SGH would hold more frequently for some combinations of life histories and stress factor, particularly when the benefactor and beneficiary species are mostly competitive and stress‐tolerant, respectively. However, we also predict that other combinations are likely to yield different results. For example, the effect of neighbours can be negative at both ends of the stress gradient when both interacting species have similar ‘competitive’ or ‘stress‐tolerant’ life histories and the abiotic stress gradient is driven by a resource (e.g. water). Synthesis. The extension of the SGH presented here provides specific and testable hypotheses to foster research and helps to reconcile potential discrepancies among previous studies. It represents an important step in incorporating the complexity and species‐specificity of potential outcomes into models and theories addressing how plant–plant interactions change along stress gradients.

@article{doi101111j13652745200801476x,
    author = "Maestre, Fernando T. and Callaway, Ragan M. and Valladares, Fernando and Lortie, Christopher J.",
    title = "Refining the stress‐gradient hypothesis for competition and facilitation in plant communities",
    year = "2009",
    journal = "Journal of Ecology",
    abstract = "Summary The stress‐gradient hypothesis (SGH) predicts that the frequency of facilitative and competitive interactions will vary inversely across abiotic stress gradients, with facilitation being more common in conditions of high abiotic stress relative to more benign abiotic conditions. With notable exceptions, most tests of the SGH have studied the interaction between a single pair or a few pairs of species, and thus have evaluated shifts in the magnitude and direction of pair‐wise interactions along stress gradients, rather than shifts in the general frequency of interactions. The SGH has been supported by numerous studies in many ecosystems, has provided a crucial foundation for studying the interplay between facilitation and competition in plant communities, and has a high heuristic value. However, recent empirical research indicates that factors like the variation among species and the nature of the stress gradient studied add complexity not considered in the SGH, creating an opportunity to extend the SGH's general conceptual framework. We suggest that one approach for extending the SGH framework is to differentiate between the original idea of how ‘common’ interactions might be along stress gradients and the ubiquitous empirical approach of studying shifts in the strength of pair‐wise interactions. Furthermore, by explicitly considering the life history of the interacting species (relative tolerance to stress vs. competitive ability) and the characteristics of the stress factor (resource vs. non‐resource) we may be able to greatly refine specific predictions relevant to the SGH. We propose that the general pattern predicted by the SGH would hold more frequently for some combinations of life histories and stress factor, particularly when the benefactor and beneficiary species are mostly competitive and stress‐tolerant, respectively. However, we also predict that other combinations are likely to yield different results. For example, the effect of neighbours can be negative at both ends of the stress gradient when both interacting species have similar ‘competitive’ or ‘stress‐tolerant’ life histories and the abiotic stress gradient is driven by a resource (e.g. water). Synthesis. The extension of the SGH presented here provides specific and testable hypotheses to foster research and helps to reconcile potential discrepancies among previous studies. It represents an important step in incorporating the complexity and species‐specificity of potential outcomes into models and theories addressing how plant–plant interactions change along stress gradients.",
    url = "https://doi.org/10.1111/j.1365-2745.2008.01476.x",
    doi = "10.1111/j.1365-2745.2008.01476.x",
    openalex = "W2166015583",
    references = "doi101111j13652745200501017x, doi1018900012965819970781958cafasa20co2"
}

The increasing availability of phylogenetic data, computing power and informatics tools has facilitated a rapid expansion of studies that apply phylogenetic data and methods to community ecology. Several key areas are reviewed in which phylogenetic information helps to resolve long-standing controversies in community ecology, challenges previous assumptions, and opens new areas of investigation. In particular, studies in phylogenetic community ecology have helped to reveal the multitude of processes driving community assembly and have demonstrated the importance of evolution in the assembly process. Phylogenetic approaches have also increased understanding of the consequences of community interactions for speciation, adaptation and extinction. Finally, phylogenetic community structure and composition holds promise for predicting ecosystem processes and impacts of global change. Major challenges to advancing these areas remain. In particular, determining the extent to which ecologically relevant traits are phylogenetically conserved or convergent, and over what temporal scale, is critical to understanding the causes of community phylogenetic structure and its evolutionary and ecosystem consequences. Harnessing phylogenetic information to understand and forecast changes in diversity and dynamics of communities is a critical step in managing and restoring the Earth's biota in a time of rapid global change.

@article{doi101111j14610248200901314x,
    author = "Cavender‐Bares, Jeannine and Kozak, Kenneth H. and Fine, Paul V. A. and Kembel, Steven W.",
    title = "The merging of community ecology and phylogenetic biology",
    year = "2009",
    journal = "Ecology Letters",
    abstract = "The increasing availability of phylogenetic data, computing power and informatics tools has facilitated a rapid expansion of studies that apply phylogenetic data and methods to community ecology. Several key areas are reviewed in which phylogenetic information helps to resolve long-standing controversies in community ecology, challenges previous assumptions, and opens new areas of investigation. In particular, studies in phylogenetic community ecology have helped to reveal the multitude of processes driving community assembly and have demonstrated the importance of evolution in the assembly process. Phylogenetic approaches have also increased understanding of the consequences of community interactions for speciation, adaptation and extinction. Finally, phylogenetic community structure and composition holds promise for predicting ecosystem processes and impacts of global change. Major challenges to advancing these areas remain. In particular, determining the extent to which ecologically relevant traits are phylogenetically conserved or convergent, and over what temporal scale, is critical to understanding the causes of community phylogenetic structure and its evolutionary and ecosystem consequences. Harnessing phylogenetic information to understand and forecast changes in diversity and dynamics of communities is a critical step in managing and restoring the Earth's biota in a time of rapid global change.",
    url = "https://doi.org/10.1111/j.1461-0248.2009.01314.x",
    doi = "10.1111/j.1461-0248.2009.01314.x",
    openalex = "W2102384105",
    references = "doi1010160006320792912013, doi101016jppees200710001, doi101016jtree200409011, doi101038nature02403, doi10108010635150802302427, doi101086282505, doi101086282687, doi101093aibsbulletin2214b, doi101098rspb20080630, doi101111j14610248200701020x, doi101111j155856461964tb01674x, doi101111j15585646200800317x, doi101126science2304728895, doi101126science2354785167, doi101126science27953592115, doi101146annurevecolsys311343, doi101146annurevecolsys33010802150448, doi1015159781400881376, doi101722611310, doi1023071435536, doi1023071446122, doi1023072259756, doi1023073071998, doi1023073544421, doi1023074549, doi105860choice432194, doi105962bhltitle56234, doi107208chicago97802261186970010001, openalexw2273605253"
}

Though many processes are involved in determining which species coexist and assemble into communities, competition is among the best studied. One hypothesis about competition's contribution to community assembly is that more closely related species are less likely to coexist. Though empirical evidence for this hypothesis is mixed, it remains a common assumption in certain phylogenetic approaches for inferring the effects of environmental filtering and competitive exclusion. Here, we relate modern coexistence theory to phylogenetic community assembly approaches to refine expectations for how species relatedness influences the outcome of competition. We argue that two types of species differences determine competitive exclusion with opposing effects on relatedness patterns. Importantly, this means that competition can sometimes eliminate more different and less related taxa, even when the traits underlying the relevant species differences are phylogenetically conserved. Our argument leads to a reinterpretation of the assembly processes inferred from community phylogenetic structure.

@article{doi101111j14610248201001509x,
    author = "Mayfield, Margaret M. and Levine, Jonathan M.",
    title = "Opposing effects of competitive exclusion on the phylogenetic structure of communities",
    year = "2010",
    journal = "Ecology Letters",
    abstract = "Though many processes are involved in determining which species coexist and assemble into communities, competition is among the best studied. One hypothesis about competition's contribution to community assembly is that more closely related species are less likely to coexist. Though empirical evidence for this hypothesis is mixed, it remains a common assumption in certain phylogenetic approaches for inferring the effects of environmental filtering and competitive exclusion. Here, we relate modern coexistence theory to phylogenetic community assembly approaches to refine expectations for how species relatedness influences the outcome of competition. We argue that two types of species differences determine competitive exclusion with opposing effects on relatedness patterns. Importantly, this means that competition can sometimes eliminate more different and less related taxa, even when the traits underlying the relevant species differences are phylogenetically conserved. Our argument leads to a reinterpretation of the assembly processes inferred from community phylogenetic structure.",
    url = "https://doi.org/10.1111/j.1461-0248.2010.01509.x",
    doi = "10.1111/j.1461-0248.2010.01509.x",
    openalex = "W1897178287",
    references = "doi101016jppees200710001, doi101016jtree200409003, doi101038nature08251, doi101073pnas5161207, doi101086282505, doi101086284133, doi101086285357, doi101086303378, doi101111j14610248200600996x, doi101111j14610248200801229x, doi101111j14610248200901314x, doi101146annurevecolsys311343, doi101146annurevecolsys33010802150448, doi101146annurevecolsys36102803095431, doi1023072402622, doi1023074072271"
}

Today's scientists are facing the enormous challenge of predicting how climate change will affect species distributions and species assemblages. To do so, ecologists are widely using phenomenological models of species distributions that mainly rely on the concept of species niche and generally ignore species' demography, species' adaptive potential, and biotic interactions. This review examines the potential role of the emerging synthetic discipline of evolutionary community ecology in improving our understanding of how climate change will alter future distribution of biodiversity. We review theoretical and empirical advances about the role of niche evolution, interspecific interactions, and their interplay in altering species geographic ranges and community assembly. We discuss potential ways to integrate complex feedbacks between ecology and evolution in ecological forecasting. We also point at a number of caveats in our understanding of the eco-evolutionary consequences of climate change and highlight several challenges for future research.

@article{doi101146annurevecolsys102209144628,
    author = "Lavergne, Sébastien and Mouquet, Nicolas and Thuiller, Wilfried and Ronce, Ophélie",
    title = "Biodiversity and Climate Change: Integrating Evolutionary and Ecological Responses of Species and Communities",
    year = "2010",
    journal = "Annual Review of Ecology Evolution and Systematics",
    abstract = "Today's scientists are facing the enormous challenge of predicting how climate change will affect species distributions and species assemblages. To do so, ecologists are widely using phenomenological models of species distributions that mainly rely on the concept of species niche and generally ignore species' demography, species' adaptive potential, and biotic interactions. This review examines the potential role of the emerging synthetic discipline of evolutionary community ecology in improving our understanding of how climate change will alter future distribution of biodiversity. We review theoretical and empirical advances about the role of niche evolution, interspecific interactions, and their interplay in altering species geographic ranges and community assembly. We discuss potential ways to integrate complex feedbacks between ecology and evolution in ecological forecasting. We also point at a number of caveats in our understanding of the eco-evolutionary consequences of climate change and highlight several challenges for future research.",
    url = "https://doi.org/10.1146/annurev-ecolsys-102209-144628",
    doi = "10.1146/annurev-ecolsys-102209-144628",
    openalex = "W2170175048",
    references = "doi101038nature01286, doi10108010635150802302427, doi101093oso97801985052350010001, doi101098rstb20090012, doi101111j13652435200701275x, doi101111j13652435200701278x, doi101111j13652435200701289x, doi101111j14610248200500792x, doi101111j14610248200500812x, doi101146annurevecolsys110308120159, doi101146annurevecolsys110308120317, doi101146annurevecolsys311343, doi101146annurevecolsys37091305110100, doi1015159780691206912, doi1023072260079, doi1023073071998, doi105860choice185809, doi105962bhltitle59991, openalexw2045291252, openalexw2151235472"
}

Understanding how communities of living organisms assemble has been a central question in ecology since the early days of the discipline. Disentangling the different processes involved in community assembly is not only interesting in itself but also crucial for an understanding of how communities will behave under future environmental scenarios. The traditional concept of assembly rules reflects the notion that species do not co-occur randomly but are restricted in their co-occurrence by interspecific competition. This concept can be redefined in a more general framework where the co-occurrence of species is a product of chance, historical patterns of speciation and migration, dispersal, abiotic environmental factors, and biotic interactions, with none of these processes being mutually exclusive. Here we present a survey and meta-analyses of 59 papers that compare observed patterns in plant communities with null models simulating random patterns of species assembly. According to the type of data under study and the different methods that are applied to detect community assembly, we distinguish four main types of approach in the published literature: species co-occurrence, niche limitation, guild proportionality and limiting similarity. Results from our meta-analyses suggest that non-random co-occurrence of plant species is not a widespread phenomenon. However, whether this finding reflects the individualistic nature of plant communities or is caused by methodological shortcomings associated with the studies considered cannot be discerned from the available metadata. We advocate that more thorough surveys be conducted using a set of standardized methods to test for the existence of assembly rules in data sets spanning larger biological and geographical scales than have been considered until now. We underpin this general advice with guidelines that should be considered in future assembly rules research. This will enable us to draw more accurate and general conclusions about the non-random aspect of assembly in plant communities.

@article{doi101111j1469185x201100187x,
    author = "Götzenberger, Lars and de Bello, Francesco and Bråthen, Kari Anne and Davison, John and Dubuis, Anne and Guisan, Antoine and Lepš, Jan and Lindborg, Regina and Moora, Mari and Pärtel, Meelis and Pellissier, Loïc and Pottier, Julien and Vittoz, Pascal and Zobel, Kristjan and Zobel, Martin",
    title = "Ecological assembly rules in plant communities—approaches, patterns and prospects",
    year = "2011",
    journal = "Biological reviews/Biological reviews of the Cambridge Philosophical Society",
    abstract = "Understanding how communities of living organisms assemble has been a central question in ecology since the early days of the discipline. Disentangling the different processes involved in community assembly is not only interesting in itself but also crucial for an understanding of how communities will behave under future environmental scenarios. The traditional concept of assembly rules reflects the notion that species do not co-occur randomly but are restricted in their co-occurrence by interspecific competition. This concept can be redefined in a more general framework where the co-occurrence of species is a product of chance, historical patterns of speciation and migration, dispersal, abiotic environmental factors, and biotic interactions, with none of these processes being mutually exclusive. Here we present a survey and meta-analyses of 59 papers that compare observed patterns in plant communities with null models simulating random patterns of species assembly. According to the type of data under study and the different methods that are applied to detect community assembly, we distinguish four main types of approach in the published literature: species co-occurrence, niche limitation, guild proportionality and limiting similarity. Results from our meta-analyses suggest that non-random co-occurrence of plant species is not a widespread phenomenon. However, whether this finding reflects the individualistic nature of plant communities or is caused by methodological shortcomings associated with the studies considered cannot be discerned from the available metadata. We advocate that more thorough surveys be conducted using a set of standardized methods to test for the existence of assembly rules in data sets spanning larger biological and geographical scales than have been considered until now. We underpin this general advice with guidelines that should be considered in future assembly rules research. This will enable us to draw more accurate and general conclusions about the non-random aspect of assembly in plant communities.",
    url = "https://doi.org/10.1111/j.1469-185x.2011.00187.x",
    doi = "10.1111/j.1469-185x.2011.00187.x",
    openalex = "W2072811688",
    references = "doi101111j14610248201001509x"
}

A major goal of microbial community ecology is to understand the forces that structure community composition. Deterministic selection by specific environmental factors is sometimes important, but in other cases stochastic or ecologically neutral processes dominate. Lacking is a unified conceptual framework aiming to understand why deterministic processes dominate in some contexts but not others. Here we work toward such a framework. By testing predictions derived from general ecological theory we aim to uncover factors that govern the relative influences of deterministic and stochastic processes. We couple spatiotemporal data on subsurface microbial communities and environmental parameters with metrics and null models of within and between community phylogenetic composition. Testing for phylogenetic signal in organismal niches showed that more closely related taxa have more similar habitat associations. Community phylogenetic analyses further showed that ecologically similar taxa coexist to a greater degree than expected by chance. Environmental filtering thus deterministically governs subsurface microbial community composition. More importantly, the influence of deterministic environmental filtering relative to stochastic factors was maximized at both ends of an environmental variation gradient. A stronger role of stochastic factors was, however, supported through analyses of phylogenetic temporal turnover. Although phylogenetic turnover was on average faster than expected, most pairwise comparisons were not themselves significantly non-random. The relative influence of deterministic environmental filtering over community dynamics was elevated, however, in the most temporally and spatially variable environments. Our results point to general rules governing the relative influences of stochastic and deterministic processes across micro- and macro-organisms.

@article{doi101038ismej201222,
    author = "Stegen, James and Lin, Xueju and Konopka, Allan and Fredrickson, James K.",
    title = "Stochastic and deterministic assembly processes in subsurface microbial communities",
    year = "2012",
    journal = "The ISME Journal",
    abstract = "A major goal of microbial community ecology is to understand the forces that structure community composition. Deterministic selection by specific environmental factors is sometimes important, but in other cases stochastic or ecologically neutral processes dominate. Lacking is a unified conceptual framework aiming to understand why deterministic processes dominate in some contexts but not others. Here we work toward such a framework. By testing predictions derived from general ecological theory we aim to uncover factors that govern the relative influences of deterministic and stochastic processes. We couple spatiotemporal data on subsurface microbial communities and environmental parameters with metrics and null models of within and between community phylogenetic composition. Testing for phylogenetic signal in organismal niches showed that more closely related taxa have more similar habitat associations. Community phylogenetic analyses further showed that ecologically similar taxa coexist to a greater degree than expected by chance. Environmental filtering thus deterministically governs subsurface microbial community composition. More importantly, the influence of deterministic environmental filtering relative to stochastic factors was maximized at both ends of an environmental variation gradient. A stronger role of stochastic factors was, however, supported through analyses of phylogenetic temporal turnover. Although phylogenetic turnover was on average faster than expected, most pairwise comparisons were not themselves significantly non-random. The relative influence of deterministic environmental filtering over community dynamics was elevated, however, in the most temporally and spatially variable environments. Our results point to general rules governing the relative influences of stochastic and deterministic processes across micro- and macro-organisms.",
    url = "https://doi.org/10.1038/ismej.2012.22",
    doi = "10.1038/ismej.2012.22",
    openalex = "W2075536793",
    references = "doi101086652373, doi101126science28454232124, doi101146annurevecolsys311343, doi101146annurevecolsys33010802150448, openalexw1493831303"
}

Although research on the role of competitive interactions during community assembly began decades ago, a recent revival of interest has led to new discoveries and research opportunities. Using contemporary coexistence theory that emphasizes stabilizing niche differences and relative fitness differences, we evaluate three empirical approaches for studying community assembly. We show that experimental manipulations of the abiotic or biotic environment, assessments of trait-phylogeny-environment relationships, and investigations of frequency-dependent population growth all suggest strong influences of stabilizing niche differences and fitness differences on the outcome of plant community assembly. Nonetheless, due to the limitations of these approaches applied in isolation, we still have a poor understanding of which niche axes and which traits determine the outcome of competition and community structure. Combining current approaches represents our best chance of achieving this goal, which is fundamental to conceptual ecology and to the management of plant communities under global change.

@article{doi101146annurevecolsys110411160411,
    author = "HilleRisLambers, Janneke and Adler, Peter B. and Harpole, W. Stanley and Levine, Jonathan M. and Mayfield, Margaret M.",
    title = "Rethinking Community Assembly through the Lens of Coexistence Theory",
    year = "2012",
    journal = "Annual Review of Ecology Evolution and Systematics",
    abstract = "Although research on the role of competitive interactions during community assembly began decades ago, a recent revival of interest has led to new discoveries and research opportunities. Using contemporary coexistence theory that emphasizes stabilizing niche differences and relative fitness differences, we evaluate three empirical approaches for studying community assembly. We show that experimental manipulations of the abiotic or biotic environment, assessments of trait-phylogeny-environment relationships, and investigations of frequency-dependent population growth all suggest strong influences of stabilizing niche differences and fitness differences on the outcome of plant community assembly. Nonetheless, due to the limitations of these approaches applied in isolation, we still have a poor understanding of which niche axes and which traits determine the outcome of competition and community structure. Combining current approaches represents our best chance of achieving this goal, which is fundamental to conceptual ecology and to the management of plant communities under global change.",
    url = "https://doi.org/10.1146/annurev-ecolsys-110411-160411",
    doi = "10.1146/annurev-ecolsys-110411-160411",
    openalex = "W2098490582",
    references = "doi101016jtree200409011, doi101038nature08251, doi101086283164, doi101111j14610248200600996x, doi101111j14610248201001509x, doi101126science1169640, doi1018901012641"
}

Summary One of the most pervasive concepts in the study of community assembly is the metaphor of the environmental filter, which refers to abiotic factors that prevent the establishment or persistence of species in a particular location. The metaphor has its origins in the study of community change during succession and in plant community dynamics, although it has gained considerable attention recently as part of a surge of interest in functional trait and phylogenetic‐based approaches to the study of communities. While the filtering metaphor has clear utility in some circumstances, it has been challenging to reconcile the environmental filtering concept with recent developments in ecological theory related to species coexistence. These advances suggest that the evidence used in many studies to assess environmental filtering is insufficient to distinguish filtering from the outcome of biotic interactions. We re‐examine the environmental filtering metaphor from the perspective of coexistence theory. In an effort to move the discussion forward, we present a simple framework for considering the role of the environment in shaping community membership, review the literature to document the evidence typically used in environmental filtering studies and highlight research challenges to address in coming years. The current usage of the environmental filtering term in empirical studies likely overstates the role abiotic tolerances play in shaping community structure. We recommend that the term ‘environmental filtering’ only be used to refer to cases where the abiotic environment prevents establishment or persistence in the absence of biotic interactions, although only 15% of the studies in our review presented such evidence. Finally, we urge community ecologists to consider additional mechanisms aside from environmental filtering by which the abiotic environment can shape community pattern.

@article{doi1011111365243512345,
    author = "Kraft, Nathan J. B. and Adler, Peter B. and Godoy, Óscar and James, Emily C. and Fuller, S. Cynthia and Levine, Jonathan M.",
    title = "Community assembly, coexistence and the environmental filtering metaphor",
    year = "2014",
    journal = "Functional Ecology",
    abstract = "Summary One of the most pervasive concepts in the study of community assembly is the metaphor of the environmental filter, which refers to abiotic factors that prevent the establishment or persistence of species in a particular location. The metaphor has its origins in the study of community change during succession and in plant community dynamics, although it has gained considerable attention recently as part of a surge of interest in functional trait and phylogenetic‐based approaches to the study of communities. While the filtering metaphor has clear utility in some circumstances, it has been challenging to reconcile the environmental filtering concept with recent developments in ecological theory related to species coexistence. These advances suggest that the evidence used in many studies to assess environmental filtering is insufficient to distinguish filtering from the outcome of biotic interactions. We re‐examine the environmental filtering metaphor from the perspective of coexistence theory. In an effort to move the discussion forward, we present a simple framework for considering the role of the environment in shaping community membership, review the literature to document the evidence typically used in environmental filtering studies and highlight research challenges to address in coming years. The current usage of the environmental filtering term in empirical studies likely overstates the role abiotic tolerances play in shaping community structure. We recommend that the term ‘environmental filtering’ only be used to refer to cases where the abiotic environment prevents establishment or persistence in the absence of biotic interactions, although only 15\% of the studies in our review presented such evidence. Finally, we urge community ecologists to consider additional mechanisms aside from environmental filtering by which the abiotic environment can shape community pattern.",
    url = "https://doi.org/10.1111/1365-2435.12345",
    doi = "10.1111/1365-2435.12345",
    openalex = "W2140575676",
    references = "doi101038nature08251, doi101046j14724642200000083x, doi101111j001438202003tb00285x, doi101111j14610248200901314x, doi101111j14610248201001509x"
}

The order and timing of species immigration during community assembly can affect species abundances at multiple spatial scales. Known as priority effects, these effects cause historical contingency in the structure and function of communities, resulting in alternative stable states, alternative transient states, or compositional cycles. The mechanisms of priority effects fall into two categories, niche preemption and niche modification, and the conditions for historical contingency by priority effects can be organized into two groups, those regarding regional species pool properties and those regarding local population dynamics. Specifically, two requirements must be satisfied for historical contingency to occur: The regional pool contains species that can together cause priority effects, and local dynamics are rapid enough for early-arriving species to preempt or modify niches before other species arrive. Organizing current knowledge this way reveals an outstanding key question: How are regional species pools that yield priority effects generated and maintained?

@article{doi101146annurevecolsys110411160340,
    author = "Fukami, Tadashi",
    title = "Historical Contingency in Community Assembly: Integrating Niches, Species Pools, and Priority Effects",
    year = "2015",
    journal = "Annual Review of Ecology Evolution and Systematics",
    abstract = "The order and timing of species immigration during community assembly can affect species abundances at multiple spatial scales. Known as priority effects, these effects cause historical contingency in the structure and function of communities, resulting in alternative stable states, alternative transient states, or compositional cycles. The mechanisms of priority effects fall into two categories, niche preemption and niche modification, and the conditions for historical contingency by priority effects can be organized into two groups, those regarding regional species pool properties and those regarding local population dynamics. Specifically, two requirements must be satisfied for historical contingency to occur: The regional pool contains species that can together cause priority effects, and local dynamics are rapid enough for early-arriving species to preempt or modify niches before other species arrive. Organizing current knowledge this way reveals an outstanding key question: How are regional species pools that yield priority effects generated and maintained?",
    url = "https://doi.org/10.1146/annurev-ecolsys-110411-160340",
    doi = "10.1146/annurev-ecolsys-110411-160340",
    openalex = "W2153248731",
    references = "doi101007978146124018114, doi101086284105, doi101111j13652435200701275x, doi101111j14610248200400608x, doi1023073545850, doi105962bhltitle56234"
}

For two competing species, intraspecific competition must exceed interspecific competition for coexistence. To generalize this well-known criterion to multiple competing species, one must take into account both the distribution of interaction strengths and community structure. Here we derive a multispecies generalization of the two-species rule in the context of symmetric Lotka-Volterra competition and obtain explicit stability conditions for random competitive communities. We then explore the influence of community structure on coexistence. Results show that both the most and least stabilized cases have striking global structures, with a nested pattern emerging in both cases. The distribution of intraspecific coefficients leading to the most and least stabilized communities also follows a predictable pattern that can be justified analytically. In addition, we show that the size of the parameter space allowing for feasible communities always increases with the strength of intraspecific effects in a characteristic way that is independent of the interspecific interaction structure. We conclude by discussing possible extensions of our results to nonsymmetric competition.

@article{doi101086686901,
    author = "Barabás, György and Smith, Matthew J. and Allesina, Stefano",
    title = "The Effect of Intra- and Interspecific Competition on Coexistence in Multispecies Communities",
    year = "2016",
    journal = "The American Naturalist",
    abstract = "For two competing species, intraspecific competition must exceed interspecific competition for coexistence. To generalize this well-known criterion to multiple competing species, one must take into account both the distribution of interaction strengths and community structure. Here we derive a multispecies generalization of the two-species rule in the context of symmetric Lotka-Volterra competition and obtain explicit stability conditions for random competitive communities. We then explore the influence of community structure on coexistence. Results show that both the most and least stabilized cases have striking global structures, with a nested pattern emerging in both cases. The distribution of intraspecific coefficients leading to the most and least stabilized communities also follows a predictable pattern that can be justified analytically. In addition, we show that the size of the parameter space allowing for feasible communities always increases with the strength of intraspecific effects in a characteristic way that is independent of the interspecific interaction structure. We conclude by discussing possible extensions of our results to nonsymmetric competition.",
    url = "https://doi.org/10.1086/686901",
    doi = "10.1086/686901",
    openalex = "W2394725158",
    references = "doi1010160040580970900390, doi101038nature08251, doi101086282505, doi101093oso97801988358510010001, doi101111j14610248200600996x, doi101111j14610248200701094x, doi101111j193974452001tb00075x, doi1011370129022, doi10113719780898719147, doi101146annurevecolsys311343, doi1023072407184"
}

@article{doi101038s415590170109,
    author = "Friedman, Jonathan and Higgins, Logan M. and Gore, Jeff",
    title = "Community structure follows simple assembly rules in microbial microcosms",
    year = "2017",
    journal = "Nature Ecology \& Evolution",
    url = "https://doi.org/10.1038/s41559-017-0109",
    doi = "10.1038/s41559-017-0109",
    openalex = "W2952570005"
}

Understanding the mechanisms controlling community diversity, functions, succession, and biogeography is a central, but poorly understood, topic in ecology, particularly in microbial ecology. Although stochastic processes are believed to play nonnegligible roles in shaping community structure, their importance relative to deterministic processes is hotly debated. The importance of ecological stochasticity in shaping microbial community structure is far less appreciated. Some of the main reasons for such heavy debates are the difficulty in defining stochasticity and the diverse methods used for delineating stochasticity. Here, we provide a critical review and synthesis of data from the most recent studies on stochastic community assembly in microbial ecology. We then describe both stochastic and deterministic components embedded in various ecological processes, including selection, dispersal, diversification, and drift. We also describe different approaches for inferring stochasticity from observational diversity patterns and highlight experimental approaches for delineating ecological stochasticity in microbial communities. In addition, we highlight research challenges, gaps, and future directions for microbial community assembly research.

@article{doi101128mmbr0000217,
    author = "Zhou, Jizhong and Ning, Daliang",
    title = "Stochastic Community Assembly: Does It Matter in Microbial Ecology?",
    year = "2017",
    journal = "Microbiology and Molecular Biology Reviews",
    abstract = "Understanding the mechanisms controlling community diversity, functions, succession, and biogeography is a central, but poorly understood, topic in ecology, particularly in microbial ecology. Although stochastic processes are believed to play nonnegligible roles in shaping community structure, their importance relative to deterministic processes is hotly debated. The importance of ecological stochasticity in shaping microbial community structure is far less appreciated. Some of the main reasons for such heavy debates are the difficulty in defining stochasticity and the diverse methods used for delineating stochasticity. Here, we provide a critical review and synthesis of data from the most recent studies on stochastic community assembly in microbial ecology. We then describe both stochastic and deterministic components embedded in various ecological processes, including selection, dispersal, diversification, and drift. We also describe different approaches for inferring stochasticity from observational diversity patterns and highlight experimental approaches for delineating ecological stochasticity in microbial communities. In addition, we highlight research challenges, gaps, and future directions for microbial community assembly research.",
    url = "https://doi.org/10.1128/mmbr.00002-17",
    doi = "10.1128/mmbr.00002-17",
    openalex = "W2761955173",
    references = "doi101016jshpsc200806005, doi101016jtree201206001, doi10103835012228, doi101038nature06813, doi101038nature11148, doi101038nature14486, doi101038nmicrobiol201648, doi101038nrmicro1341, doi101086282505, doi101086381004, doi101086652373, doi101093bioinformaticsbtq166, doi1011111365243512425, doi101111j144299931993tb00438x, doi101111j14429993200101070ppx, doi101111j14610248200400608x, doi101111j14610248200600996x, doi101111j14610248200901314x, doi101111j14610248201001509x, doi101126science27953592115, doi101126science28454232124, doi101126scienceaac9323, doi101128mmbr0005112, doi101146annurevecolsys311343, doi101146annurevecolsys33010802150448, doi1015159781400881376, doi1023072259756, doi1023072531471, doi1023073071998, openalexw2273605253"
}

Abstract Understanding the role of competition in structuring communities requires that we quantify competitive ability in a way that permits us to predict the outcome of competition over the long term. Given such a clear goal for a process that has been the focus of ecological research for decades, there is surprisingly little consensus on how to measure competitive ability, with up to 50 different metrics currently proposed. Using competitive population dynamics as a foundation, we define competitive ability—the ability of one species to exclude another—using quantitative theoretical models of population dynamics to isolate the key parameters that are known to predict competitive outcomes. Based on the definition of competitive ability we identify the empirical requirements and describe straightforward methods for quantifying competitive ability in future empirical studies. In doing so, our analysis also allows us to identify why many existing approaches to studying competition are unsuitable for quantifying competitive ability. Synthesis. Competitive ability is precisely defined starting from models of competitive population dynamics. Quantifying competitive ability in a theoretically justified manner is straightforward using experimental designs readily applied to studies of competition in the laboratory and field.

@article{doi1011111365274512954,
    author = "Hart, Simon P. and Freckleton, Robert P. and Levine, Jonathan M.",
    title = "How to quantify competitive ability",
    year = "2018",
    journal = "Journal of Ecology",
    abstract = "Abstract Understanding the role of competition in structuring communities requires that we quantify competitive ability in a way that permits us to predict the outcome of competition over the long term. Given such a clear goal for a process that has been the focus of ecological research for decades, there is surprisingly little consensus on how to measure competitive ability, with up to 50 different metrics currently proposed. Using competitive population dynamics as a foundation, we define competitive ability—the ability of one species to exclude another—using quantitative theoretical models of population dynamics to isolate the key parameters that are known to predict competitive outcomes. Based on the definition of competitive ability we identify the empirical requirements and describe straightforward methods for quantifying competitive ability in future empirical studies. In doing so, our analysis also allows us to identify why many existing approaches to studying competition are unsuitable for quantifying competitive ability. Synthesis. Competitive ability is precisely defined starting from models of competitive population dynamics. Quantifying competitive ability in a theoretically justified manner is straightforward using experimental designs readily applied to studies of competition in the laboratory and field.",
    url = "https://doi.org/10.1111/1365-2745.12954",
    doi = "10.1111/1365-2745.12954",
    openalex = "W2792151033",
    references = "doi101002ecm1263"
}

Theory predicts that intraspecific competition should be stronger than interspecific competition for any pair of stably coexisting species, yet previous literature reviews found little support for this pattern. We screened over 5400 publications and identified 39 studies that quantified phenomenological intraspecific and interspecific interactions in terrestrial plant communities. Of the 67% of species pairs in which both intra- and interspecific effects were negative (competitive), intraspecific competition was, on average, four to five-fold stronger than interspecific competition. Of the remaining pairs, 93% featured intraspecific competition and interspecific facilitation, a situation that stabilises coexistence. The difference between intra- and interspecific effects tended to be larger in observational than experimental data sets, in field than greenhouse studies, and in studies that quantified population growth over the full life cycle rather than single fitness components. Our results imply that processes promoting stable coexistence at local scales are common and consequential across terrestrial plant communities.

@article{doi101111ele13098,
    author = "Adler, Peter B. and Smull, Danielle M and Beard, Karen H. and Choi, Ryan T. and Furniss, Tucker J. and Kulmatiski, Andrew and Meiners, Joan M. and Tredennick, Andrew T. and Veblen, Kari E.",
    title = "Competition and coexistence in plant communities: intraspecific competition is stronger than interspecific competition",
    year = "2018",
    journal = "Ecology Letters",
    abstract = "Theory predicts that intraspecific competition should be stronger than interspecific competition for any pair of stably coexisting species, yet previous literature reviews found little support for this pattern. We screened over 5400 publications and identified 39 studies that quantified phenomenological intraspecific and interspecific interactions in terrestrial plant communities. Of the 67\% of species pairs in which both intra- and interspecific effects were negative (competitive), intraspecific competition was, on average, four to five-fold stronger than interspecific competition. Of the remaining pairs, 93\% featured intraspecific competition and interspecific facilitation, a situation that stabilises coexistence. The difference between intra- and interspecific effects tended to be larger in observational than experimental data sets, in field than greenhouse studies, and in studies that quantified population growth over the full life cycle rather than single fitness components. Our results imply that processes promoting stable coexistence at local scales are common and consequential across terrestrial plant communities.",
    url = "https://doi.org/10.1111/ele.13098",
    doi = "10.1111/ele.13098",
    openalex = "W2811105108",
    references = "doi101038118558a0, doi101038nature22898"
}

Stochasticity is a core component of ecology, as it underlies key processes that structure and create variability in nature. Despite its fundamental importance in ecological systems, the concept is often treated as synonymous with unpredictability in community ecology, and studies tend to focus on single forms of stochasticity rather than taking a more holistic view. This has led to multiple narratives for how stochasticity mediates community dynamics. Here, we present a framework that describes how different forms of stochasticity (notably demographic and environmental stochasticity) combine to provide underlying and predictable structure in diverse communities. This framework builds on the deep ecological understanding of stochastic processes acting at individual and population levels and in modules of a few interacting species. We support our framework with a mathematical model that we use to synthesize key literature, demonstrating that stochasticity is more than simple uncertainty. Rather, stochasticity has profound and predictable effects on community dynamics that are critical for understanding how diversity is maintained. We propose next steps that ecologists might use to explore the role of stochasticity for structuring communities in theoretical and empirical systems, and thereby enhance our understanding of community dynamics.

@article{doi101002ecy2922,
    author = "Shoemaker, Lauren G. and Sullivan, Lauren L. and Donohue, Ian and Cabral, Juliano Sarmento and Williams, Ryan J. and Mayfield, Margaret M. and Chase, Jonathan M. and Chu, Chengjin and Harpole, W. Stanley and Huth, Andreas and HilleRisLambers, Janneke and James, Aubrie R. M. and Kraft, Nathan J. B. and May, Felix and Muthukrishnan, Ranjan and Satterlee, S. Andrew and Taubert, Franziska and Wang, Xugao and Wiegand, Thorsten and Yang, Qiang and Abbott, Karen C.",
    title = "Integrating the underlying structure of stochasticity into community ecology",
    year = "2019",
    journal = "Ecology",
    abstract = "Stochasticity is a core component of ecology, as it underlies key processes that structure and create variability in nature. Despite its fundamental importance in ecological systems, the concept is often treated as synonymous with unpredictability in community ecology, and studies tend to focus on single forms of stochasticity rather than taking a more holistic view. This has led to multiple narratives for how stochasticity mediates community dynamics. Here, we present a framework that describes how different forms of stochasticity (notably demographic and environmental stochasticity) combine to provide underlying and predictable structure in diverse communities. This framework builds on the deep ecological understanding of stochastic processes acting at individual and population levels and in modules of a few interacting species. We support our framework with a mathematical model that we use to synthesize key literature, demonstrating that stochasticity is more than simple uncertainty. Rather, stochasticity has profound and predictable effects on community dynamics that are critical for understanding how diversity is maintained. We propose next steps that ecologists might use to explore the role of stochasticity for structuring communities in theoretical and empirical systems, and thereby enhance our understanding of community dynamics.",
    url = "https://doi.org/10.1002/ecy.2922",
    doi = "10.1002/ecy.2922",
    openalex = "W2981737754",
    references = "doi101002ecm1263, doi101002ecm1302, doi101016jtree201201014"
}

Motivated by both analytical tractability and empirical practicality, community ecologists have long treated the species pair as the fundamental unit of study. This notwithstanding, the challenge of understanding more complex systems has repeatedly generated interest in the role of so-called higher-order interactions (HOIs) imposed by species beyond the focal pair. Here we argue that HOIs - defined as non-additive effects of density on per capita growth - are best interpreted as emergent properties of phenomenological models (e.g. Lotka-Volterra competition) rather than as distinct 'ecological processes' in their own right. Using simulations of consumer-resource models, we explore the mechanisms and system properties that give rise to HOIs in observational data. We demonstrate that HOIs emerge under all but the most restrictive of assumptions, and that incorporating non-additivity into phenomenological models improves the quantitative and qualitative accuracy of model predictions. Notably, we also observe that HOIs derive primarily from mechanisms and system properties that apply equally to single-species or pairwise systems as they do to more diverse communities. Consequently, there exists a strong mandate for further recognition of non-additive effects in both theoretical and empirical research.

@article{doi101111ele13211,
    author = "Letten, Andrew D. and Stouffer, Daniel B.",
    title = "The mechanistic basis for higher-order interactions and non-additivity in competitive communities",
    year = "2019",
    journal = "Ecology Letters",
    abstract = "Motivated by both analytical tractability and empirical practicality, community ecologists have long treated the species pair as the fundamental unit of study. This notwithstanding, the challenge of understanding more complex systems has repeatedly generated interest in the role of so-called higher-order interactions (HOIs) imposed by species beyond the focal pair. Here we argue that HOIs - defined as non-additive effects of density on per capita growth - are best interpreted as emergent properties of phenomenological models (e.g. Lotka-Volterra competition) rather than as distinct 'ecological processes' in their own right. Using simulations of consumer-resource models, we explore the mechanisms and system properties that give rise to HOIs in observational data. We demonstrate that HOIs emerge under all but the most restrictive of assumptions, and that incorporating non-additivity into phenomenological models improves the quantitative and qualitative accuracy of model predictions. Notably, we also observe that HOIs derive primarily from mechanisms and system properties that apply equally to single-species or pairwise systems as they do to more diverse communities. Consequently, there exists a strong mandate for further recognition of non-additive effects in both theoretical and empirical research.",
    url = "https://doi.org/10.1111/ele.13211",
    doi = "10.1111/ele.13211",
    openalex = "W2911484707",
    references = "doi1010160040580970900390, doi101017cbo9780511530043, doi101038269471a0, doi101038nature00823, doi10106314823332, doi101086282505, doi101086686901, doi101146annurevecolsys311343, doi1018637jssv033i03, doi1018637jssv033i09, doi102307jctvcm4g37"
}

Community coalescence, the mixing of different communities, is widespread throughout microbial ecology. Coalescence can result in approximately equal contributions from the founding communities or dominance of one community over another. These different outcomes have ramifications for community structure and function in natural communities, and the use of microbial communities in biotechnology and medicine. However, we have little understanding of when a particular outcome might be expected. Here, we integrate existing theory and data to speculate on how a crucial characteristic of microbial communities-the type of species interaction that dominates the community-might affect the outcome of microbial community coalescence. Given the often comparable timescales of microbial ecology and microevolution, we explicitly consider ecological and evolutionary dynamics, and their interplay, in determining coalescence outcomes. This article is part of the theme issue 'Conceptual challenges in microbial community ecology'.

@article{doi101098rstb20190252,
    author = "Castledine, Meaghan and Sierocinski, Pawel and Padfield, Daniel and Buckling, Angus",
    title = "Community coalescence: an eco-evolutionary perspective",
    year = "2020",
    journal = "Philosophical Transactions of the Royal Society B Biological Sciences",
    abstract = "Community coalescence, the mixing of different communities, is widespread throughout microbial ecology. Coalescence can result in approximately equal contributions from the founding communities or dominance of one community over another. These different outcomes have ramifications for community structure and function in natural communities, and the use of microbial communities in biotechnology and medicine. However, we have little understanding of when a particular outcome might be expected. Here, we integrate existing theory and data to speculate on how a crucial characteristic of microbial communities-the type of species interaction that dominates the community-might affect the outcome of microbial community coalescence. Given the often comparable timescales of microbial ecology and microevolution, we explicitly consider ecological and evolutionary dynamics, and their interplay, in determining coalescence outcomes. This article is part of the theme issue 'Conceptual challenges in microbial community ecology'.",
    url = "https://doi.org/10.1098/rstb.2019.0252",
    doi = "10.1098/rstb.2019.0252",
    openalex = "W3012730530",
    references = "doi1011111365274513035"
}

The metacommunity concept has the potential to integrate local and regional dynamics within a general community ecology framework. To this end, the concept must move beyond the discrete archetypes that have largely defined it (e.g. neutral vs. species sorting) and better incorporate local scale species interactions and coexistence mechanisms. Here, we present a fundamental reconception of the framework that explicitly links local coexistence theory to the spatial processes inherent to metacommunity theory, allowing for a continuous range of competitive community dynamics. These dynamics emerge from the three underlying processes that shape ecological communities: (1) density-independent responses to abiotic conditions, (2) density-dependent biotic interactions and (3) dispersal. Stochasticity is incorporated in the demographic realisation of each of these processes. We formalise this framework using a simulation model that explores a wide range of competitive metacommunity dynamics by varying the strength of the underlying processes. Using this model and framework, we show how existing theories, including the traditional metacommunity archetypes, are linked by this common set of processes. We then use the model to generate new hypotheses about how the three processes combine to interactively shape diversity, functioning and stability within metacommunities.

@article{doi101111ele13568,
    author = "Thompson, Patrick L. and Guzman, Laura Melissa and Meester, Luc De and Horváth, Zsófia and Ptáčník, Robert and Vanschoenwinkel, Bram and Viana, Duarte S. and Chase, Jonathan M.",
    title = "A process‐based metacommunity framework linking local and regional scale community ecology",
    year = "2020",
    journal = "Ecology Letters",
    abstract = "The metacommunity concept has the potential to integrate local and regional dynamics within a general community ecology framework. To this end, the concept must move beyond the discrete archetypes that have largely defined it (e.g. neutral vs. species sorting) and better incorporate local scale species interactions and coexistence mechanisms. Here, we present a fundamental reconception of the framework that explicitly links local coexistence theory to the spatial processes inherent to metacommunity theory, allowing for a continuous range of competitive community dynamics. These dynamics emerge from the three underlying processes that shape ecological communities: (1) density-independent responses to abiotic conditions, (2) density-dependent biotic interactions and (3) dispersal. Stochasticity is incorporated in the demographic realisation of each of these processes. We formalise this framework using a simulation model that explores a wide range of competitive metacommunity dynamics by varying the strength of the underlying processes. Using this model and framework, we show how existing theories, including the traditional metacommunity archetypes, are linked by this common set of processes. We then use the model to generate new hypotheses about how the three processes combine to interactively shape diversity, functioning and stability within metacommunities.",
    url = "https://doi.org/10.1111/ele.13568",
    doi = "10.1111/ele.13568",
    openalex = "W3042819938",
    references = "doi101002ecm1263, doi10103835083573, doi101038s4155901704025, doi101086652373, doi101086686901, doi101093oso97801988358510010001, doi101111j14610248200400608x, doi101137141000671, doi101146annurevecolsys311343, doi1018900012965820020831771tuntob20co2, doi1023071440619, doi1023071939377, doi1023072259756, doi104039ent912935"
}

Mycorrhizal fungi provide plants with a range of benefits, including mineral nutrients and protection from stress and pathogens. Here we synthesize current information about how the presence and type of mycorrhizal association affect plant communities. We argue that mycorrhizal fungi regulate seedling establishment and species coexistence through stabilizing and equalizing mechanisms such as soil nutrient partitioning, feedback to soil antagonists, differential mycorrhizal benefits, and nutrient trade. Mycorrhizal fungi have strong effects on plant population and community biology, with mycorrhizal type-specific effects on seed dispersal, seedling establishment, and soil niche differentiation, as well as interspecific and intraspecific competition and hence plant diversity.

@article{doi101126scienceaba1223,
    author = "Tedersoo, Leho and Bahram, Mohammad and Zobel, Martin",
    title = "How mycorrhizal associations drive plant population and community biology",
    year = "2020",
    journal = "Science",
    abstract = "Mycorrhizal fungi provide plants with a range of benefits, including mineral nutrients and protection from stress and pathogens. Here we synthesize current information about how the presence and type of mycorrhizal association affect plant communities. We argue that mycorrhizal fungi regulate seedling establishment and species coexistence through stabilizing and equalizing mechanisms such as soil nutrient partitioning, feedback to soil antagonists, differential mycorrhizal benefits, and nutrient trade. Mycorrhizal fungi have strong effects on plant population and community biology, with mycorrhizal type-specific effects on seed dispersal, seedling establishment, and soil niche differentiation, as well as interspecific and intraspecific competition and hence plant diversity.",
    url = "https://doi.org/10.1126/science.aba1223",
    doi = "10.1126/science.aba1223",
    openalex = "W3008013786",
    references = "doi1011111365274513035, doi101111nph13203"
}

Costly interactions between species that arise as a by-product of ancestral similarities in communication signals are expected to persist only under specific evolutionary circumstances. Territorial aggression between species, for instance, is widely assumed to persist only when extrinsic barriers prevent niche divergence or selection in sympatry is too weak to overcome gene flow from allopatry. However, recent theoretical and comparative studies have challenged this view. Here we present a large-scale, phylogenetic analysis of the distribution and determinants of interspecific territoriality. We find that interspecific territoriality is widespread in birds and strongly associated with hybridization and resource overlap during the breeding season. Contrary to the view that territoriality only persists between species that rarely breed in the same areas or where niche divergence is constrained by habitat structure, we find that interspecific territoriality is positively associated with breeding habitat overlap and unrelated to habitat structure. Furthermore, our results provide compelling evidence that ancestral similarities in territorial signals are maintained and reinforced by selection when interspecific territoriality is adaptive. The territorial signals linked to interspecific territoriality in birds depend on the evolutionary age of interacting species, plumage at shallow (within-family) timescales, and song at deeper (between-family) timescales. Evidently, territorial interactions between species have persisted and shaped phenotypic diversity on a macroevolutionary timescale.

@article{drury2020competition,
    author = "Drury, Jonathan P. and Cowen, Madeline C. and Grether, Gregory F.",
    title = "Competition and hybridization drive interspecific territoriality in birds",
    year = "2020",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "Costly interactions between species that arise as a by-product of ancestral similarities in communication signals are expected to persist only under specific evolutionary circumstances. Territorial aggression between species, for instance, is widely assumed to persist only when extrinsic barriers prevent niche divergence or selection in sympatry is too weak to overcome gene flow from allopatry. However, recent theoretical and comparative studies have challenged this view. Here we present a large-scale, phylogenetic analysis of the distribution and determinants of interspecific territoriality. We find that interspecific territoriality is widespread in birds and strongly associated with hybridization and resource overlap during the breeding season. Contrary to the view that territoriality only persists between species that rarely breed in the same areas or where niche divergence is constrained by habitat structure, we find that interspecific territoriality is positively associated with breeding habitat overlap and unrelated to habitat structure. Furthermore, our results provide compelling evidence that ancestral similarities in territorial signals are maintained and reinforced by selection when interspecific territoriality is adaptive. The territorial signals linked to interspecific territoriality in birds depend on the evolutionary age of interacting species, plumage at shallow (within-family) timescales, and song at deeper (between-family) timescales. Evidently, territorial interactions between species have persisted and shaped phenotypic diversity on a macroevolutionary timescale.",
    url = "https://doi.org/10.1073/pnas.1921380117",
    doi = "10.1073/pnas.1921380117",
    number = "23",
    openalex = "W3015731989",
    pages = "12923-12930",
    volume = "117",
    references = "doi101016jbiocon200905006, doi101016jtree201707004, doi101038nature11631, doi101086343873, doi101093vevey016, doi101111j14679868200500503x, doi101126science1157704, doi101214ss1177011136, doi1018637jssv033i02, openalexw1549853756, openalexw2097360283"
}

Abstract Niche Theory is a central framework in ecology based on the recognition that most interactions between organisms are indirect, mediated by the biotic and abiotic dynamical environment these organisms live in. Despite its potential generality, the theory still mostly focuses on how resource–consumer dynamics mediate competition in ecological communities. However, it is being increasingly recognized that positive interactions between organisms also play an important role in driving the structure and functioning of ecological communities, from plants to microbes. In this paper, we present a unified theory of the niche that applies to both positive and negative interactions between organisms, mediated by one or two environmental factors. We show that classical concepts such as niche differences and fundamental and realized niches can naturally be expanded to facilitative and mutualistic interactions. In addition, we introduce and formalize new general niche concepts that appear exclusively in the presence of positive interactions: (1) the Allee niche, a region of environmental conditions for which a species can persist but not invade from low densities and (2) niche facilitation, when the presence of a species expands the set of environmental conditions under which a second species can invade and/or persist. To show the broad applicability of this theory, we illustrate these concepts using a diverse set of theoretical examples, from bacteria feeding on an inhibiting substrate, to nitrogen‐fixing plants and the indirect mutualism between a plant and a carnivore species. In sum, our work shows how Niche Theory provides a natural framework for positive interactions in ecology, bringing a unified perspective and new conceptual tools to study ecological systems where these positive interactions occur.

@article{doi101002ecm1458,
    author = "Koffel, Thomas and Daufresne, Tanguy and Klausmeier, Christopher A.",
    title = "From competition to facilitation and mutualism: a general theory of the niche",
    year = "2021",
    journal = "Ecological Monographs",
    abstract = "Abstract Niche Theory is a central framework in ecology based on the recognition that most interactions between organisms are indirect, mediated by the biotic and abiotic dynamical environment these organisms live in. Despite its potential generality, the theory still mostly focuses on how resource–consumer dynamics mediate competition in ecological communities. However, it is being increasingly recognized that positive interactions between organisms also play an important role in driving the structure and functioning of ecological communities, from plants to microbes. In this paper, we present a unified theory of the niche that applies to both positive and negative interactions between organisms, mediated by one or two environmental factors. We show that classical concepts such as niche differences and fundamental and realized niches can naturally be expanded to facilitative and mutualistic interactions. In addition, we introduce and formalize new general niche concepts that appear exclusively in the presence of positive interactions: (1) the Allee niche, a region of environmental conditions for which a species can persist but not invade from low densities and (2) niche facilitation, when the presence of a species expands the set of environmental conditions under which a second species can invade and/or persist. To show the broad applicability of this theory, we illustrate these concepts using a diverse set of theoretical examples, from bacteria feeding on an inhibiting substrate, to nitrogen‐fixing plants and the indirect mutualism between a plant and a carnivore species. In sum, our work shows how Niche Theory provides a natural framework for positive interactions in ecology, bringing a unified perspective and new conceptual tools to study ecological systems where these positive interactions occur.",
    url = "https://doi.org/10.1002/ecm.1458",
    doi = "10.1002/ecm.1458",
    openalex = "W3158704851",
    references = "doi1010160304380085900067, doi101016jtree201905007, doi1011111365274513035"
}

Endophytes often have dramatic effects on their host plants. Characterizing the relationships among members of these communities has focused on identifying the effects of single microbes on their host, but has generally overlooked interactions among the myriad microbes in natural communities as well as potential higher-order interactions. Network analyses offer a powerful means for characterizing patterns of interaction among microbial members of the phytobiome that may be crucial to mediating its assembly and function. We sampled twelve endophytic communities, comparing patterns of niche overlap between coexisting bacteria and fungi to evaluate the effect of nutrient supplementation on local and global competitive network structure. We found that, despite differences in the degree distribution, there were few significant differences in the global network structure of niche-overlap networks following persistent nutrient amendment. Likewise, we found idiosyncratic and weak evidence for higher-order interactions regardless of nutrient treatment. This work provides a first-time characterization of niche-overlap network structure in endophytic communities and serves as a framework for higher-resolution analyses of microbial interaction networks as a consequence and a cause of ecological variation in microbiome function.

@article{doi101038s4139602101080z,
    author = "Smith, Matthew J. and Song, Zewei and Spawn, S. and Hansen, Zoe A. and Johnson, Mitch and May, Georgiana and Borer, Elizabeth T. and Seabloom, Eric W. and Kinkel, Linda L.",
    title = "Network structure of resource use and niche overlap within the endophytic microbiome",
    year = "2021",
    journal = "The ISME Journal",
    abstract = "Endophytes often have dramatic effects on their host plants. Characterizing the relationships among members of these communities has focused on identifying the effects of single microbes on their host, but has generally overlooked interactions among the myriad microbes in natural communities as well as potential higher-order interactions. Network analyses offer a powerful means for characterizing patterns of interaction among microbial members of the phytobiome that may be crucial to mediating its assembly and function. We sampled twelve endophytic communities, comparing patterns of niche overlap between coexisting bacteria and fungi to evaluate the effect of nutrient supplementation on local and global competitive network structure. We found that, despite differences in the degree distribution, there were few significant differences in the global network structure of niche-overlap networks following persistent nutrient amendment. Likewise, we found idiosyncratic and weak evidence for higher-order interactions regardless of nutrient treatment. This work provides a first-time characterization of niche-overlap network structure in endophytic communities and serves as a framework for higher-resolution analyses of microbial interaction networks as a consequence and a cause of ecological variation in microbiome function.",
    url = "https://doi.org/10.1038/s41396-021-01080-z",
    doi = "10.1038/s41396-021-01080-z",
    openalex = "W3196173982",
    references = "doi101111ele13211"
}

Local assemblages are embedded in networks of communities connected by dispersal, and understanding the processes that mediate this local–regional interaction is central to understanding biodiversity patterns. In this network (i.e. metacommunity), the strength of dispersal relative to the intensity of environmental selection typically determines whether local communities are comprised of species well‐adapted to the local environment (i.e. species sorting) or are dominated by regionally successful species that may not be locally adapted (i.e. mass effects), which by extension determines the capacity of the landscape to sustain diversity. Despite the fundamentally spatial nature of these dispersal‐mediated processes, much of our theoretical understanding comes from spatially implicit systems, a special case of spatial structure in which patches are all connected to each other equally. In many real systems, both the connections among patches (i.e. network topology) and the distributions of environments across patches (i.e. spatial autocorrelation) are not arranged uniformly. Here, we use a metacommunity model to investigate how spatial heterogeneities may change the balance between species sorting versus mass effects and diversity outcomes. Our simulations show that, in general, the spatially implicit model generates an outlier in biodiversity patterns compared to other networks, and most likely amplifies mass effects relative to species sorting. Network topology has a strong effect on metacommunity outcome, with topologies of sparse connections and few loops promoting sorting of species into suitable patches. Spatial autocorrelation is another key factor; by interacting with spatial topology, intermediate‐scale clusters of similar patches can emerge, leading to a reduction of regional competition, and hence maintenance of gamma diversity. These results provide a better understanding of the role that complex spatial landscape structure plays in metacommunity processes, a necessary step to understanding how metacommunity processes relate to biodiversity conservation.

@article{doi101111ecog05453,
    author = "Suzuki, Yuka and Economo, Evan P.",
    title = "From species sorting to mass effects: spatial network structure mediates the shift between metacommunity archetypes",
    year = "2021",
    journal = "Ecography",
    abstract = "Local assemblages are embedded in networks of communities connected by dispersal, and understanding the processes that mediate this local–regional interaction is central to understanding biodiversity patterns. In this network (i.e. metacommunity), the strength of dispersal relative to the intensity of environmental selection typically determines whether local communities are comprised of species well‐adapted to the local environment (i.e. species sorting) or are dominated by regionally successful species that may not be locally adapted (i.e. mass effects), which by extension determines the capacity of the landscape to sustain diversity. Despite the fundamentally spatial nature of these dispersal‐mediated processes, much of our theoretical understanding comes from spatially implicit systems, a special case of spatial structure in which patches are all connected to each other equally. In many real systems, both the connections among patches (i.e. network topology) and the distributions of environments across patches (i.e. spatial autocorrelation) are not arranged uniformly. Here, we use a metacommunity model to investigate how spatial heterogeneities may change the balance between species sorting versus mass effects and diversity outcomes. Our simulations show that, in general, the spatially implicit model generates an outlier in biodiversity patterns compared to other networks, and most likely amplifies mass effects relative to species sorting. Network topology has a strong effect on metacommunity outcome, with topologies of sparse connections and few loops promoting sorting of species into suitable patches. Spatial autocorrelation is another key factor; by interacting with spatial topology, intermediate‐scale clusters of similar patches can emerge, leading to a reduction of regional competition, and hence maintenance of gamma diversity. These results provide a better understanding of the role that complex spatial landscape structure plays in metacommunity processes, a necessary step to understanding how metacommunity processes relate to biodiversity conservation.",
    url = "https://doi.org/10.1111/ecog.05453",
    doi = "10.1111/ecog.05453",
    openalex = "W3128559362",
    references = "doi101111ele13568"
}

A central assumption in most ecological models is that the interactions in a community operate only between pairs of species. However, two species may interactively affect the growth of a focal species. Although interactions among three or more species, called higher-order interactions, have the potential to modify our theoretical understanding of coexistence, ecologists lack clear expectations for how these interactions shape community structure. Here we analytically predict and numerically confirm how the variability and strength of higher-order interactions affect species coexistence. We found that as higher-order interaction strengths became more variable across species, fewer species could coexist, echoing the behavior of pairwise models. If interspecific higher-order interactions became too harmful relative to self-regulation, coexistence in diverse communities was destabilized, but coexistence was also lost when these interactions were too weak and mutualistic higher-order effects became prevalent. This behavior depended on the functional form of the interactions as the destabilizing effects of the mutualistic higher-order interactions were ameliorated when their strength saturated with species' densities. Last, we showed that more species-rich communities structured by higher-order interactions lose species more readily than their species-poor counterparts, generalizing classic results for community stability. Our work provides needed theoretical expectations for how higher-order interactions impact species coexistence in diverse communities.

@article{doi101073pnas2205063119,
    author = "Gibbs, Theo and Levin, Simon A. and Levine, Jonathan M.",
    title = "Coexistence in diverse communities with higher-order interactions",
    year = "2022",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "A central assumption in most ecological models is that the interactions in a community operate only between pairs of species. However, two species may interactively affect the growth of a focal species. Although interactions among three or more species, called higher-order interactions, have the potential to modify our theoretical understanding of coexistence, ecologists lack clear expectations for how these interactions shape community structure. Here we analytically predict and numerically confirm how the variability and strength of higher-order interactions affect species coexistence. We found that as higher-order interaction strengths became more variable across species, fewer species could coexist, echoing the behavior of pairwise models. If interspecific higher-order interactions became too harmful relative to self-regulation, coexistence in diverse communities was destabilized, but coexistence was also lost when these interactions were too weak and mutualistic higher-order effects became prevalent. This behavior depended on the functional form of the interactions as the destabilizing effects of the mutualistic higher-order interactions were ameliorated when their strength saturated with species' densities. Last, we showed that more species-rich communities structured by higher-order interactions lose species more readily than their species-poor counterparts, generalizing classic results for community stability. Our work provides needed theoretical expectations for how higher-order interactions impact species coexistence in diverse communities.",
    url = "https://doi.org/10.1073/pnas.2205063119",
    doi = "10.1073/pnas.2205063119",
    openalex = "W4306642903",
    references = "doi101111ele13211"
}

Individual decisions regarding how, why and when organisms interact with one another and with their environment scale up to shape patterns and processes in communities. Recent evidence has firmly established the prevalence of intraspecific variation in nature and its relevance in community ecology, yet challenges associated with collecting data on large numbers of individual conspecifics and heterospecifics have hampered integration of individual variation into community ecology. Nevertheless, recent technological and statistical advances in GPS-tracking, remote sensing and behavioural ecology offer a toolbox for integrating intraspecific variation into community processes. More than simply describing where organisms go, movement data provide unique information about interactions and environmental associations from which a true individual-to-community framework can be built. By linking the movement paths of both conspecifics and heterospecifics with environmental data, ecologists can now simultaneously quantify intraspecific and interspecific variation regarding the Eltonian (biotic interactions) and Grinnellian (environmental conditions) factors underpinning community assemblage and dynamics, yet substantial logistical and analytical challenges must be addressed for these approaches to realize their full potential. Across communities, empirical integration of Eltonian and Grinnellian factors can support conservation applications and reveal metacommunity dynamics via tracking-based dispersal data. As the logistical and analytical challenges associated with multi-species tracking are surmounted, we envision a future where individual movements and their ecological and environmental signatures will bring resolution to many enduring issues in community ecology.

@article{doi1011111365265613698,
    author = "Costa‐Pereira, Raul and Moll, Remington J. and Jesmer, Brett R. and Jetz, Walter",
    title = "Animal tracking moves community ecology: Opportunities and challenges",
    year = "2022",
    journal = "Journal of Animal Ecology",
    abstract = "Individual decisions regarding how, why and when organisms interact with one another and with their environment scale up to shape patterns and processes in communities. Recent evidence has firmly established the prevalence of intraspecific variation in nature and its relevance in community ecology, yet challenges associated with collecting data on large numbers of individual conspecifics and heterospecifics have hampered integration of individual variation into community ecology. Nevertheless, recent technological and statistical advances in GPS-tracking, remote sensing and behavioural ecology offer a toolbox for integrating intraspecific variation into community processes. More than simply describing where organisms go, movement data provide unique information about interactions and environmental associations from which a true individual-to-community framework can be built. By linking the movement paths of both conspecifics and heterospecifics with environmental data, ecologists can now simultaneously quantify intraspecific and interspecific variation regarding the Eltonian (biotic interactions) and Grinnellian (environmental conditions) factors underpinning community assemblage and dynamics, yet substantial logistical and analytical challenges must be addressed for these approaches to realize their full potential. Across communities, empirical integration of Eltonian and Grinnellian factors can support conservation applications and reveal metacommunity dynamics via tracking-based dispersal data. As the logistical and analytical challenges associated with multi-species tracking are surmounted, we envision a future where individual movements and their ecological and environmental signatures will bring resolution to many enduring issues in community ecology.",
    url = "https://doi.org/10.1111/1365-2656.13698",
    doi = "10.1111/1365-2656.13698",
    openalex = "W4224274476",
    references = "doi101111ele13568, doi101126scienceabg1780"
}

Abstract As major consumers of plants, insect herbivores have strong potential to influence long‐term patterns of plant abundance and community structure. Nonetheless, remarkably few manipulative experiments exclude insects for three or more years. Thus, how often, and under what conditions insects have enduring impacts remains unclear. Here we summarize the key conceptual issues and evidence from long‐term studies on the impact of insects on plant populations and communities. Models that project effects of herbivores on plant population growth, based on demographic study, suggest that insects often limit plant asymptotic population growth. However, empirical estimations of insect impacts on plant abundance based on long‐term experimental studies are few. As such, the strength and conditionality of compensatory mechanisms (such as density dependence and seedbanks) that may dampen (or exacerbate) the negative effects of insects on plant populations remains unclear. The influences of insects on plant range size and limits, invasion success and biocontrol are well‐established research areas, but are also underexplored in long‐term experiments. Insect herbivores can influence plant community structure and diversity, and change successional trajectories, often through modification of plant competitive ability. Nonetheless, effects are mostly known from mesic grasslands, take years to manifest and the extent of insect damage does not always predict their impact. The relative importance of specialist versus generalist herbivores is unclear, as is how feedbacks between plant productivity, herbivory and plant species richness contribute to community dynamics over time. Synthesis. The few existing long‐term insect suppression experiments, and many short‐term studies, suggest that insect herbivores can importantly affect plant populations and communities. Although challenging, experimental studies spanning multiple plant generations could greatly enhance our ability to develop a more predictive framework for how insect herbivores influence plant populations and communities.

@article{doi1011111365274513996,
    author = "Agrawal, Anurag A. and Maron, John L.",
    title = "Long‐term impacts of insect herbivores on plant populations and communities",
    year = "2022",
    journal = "Journal of Ecology",
    abstract = "Abstract As major consumers of plants, insect herbivores have strong potential to influence long‐term patterns of plant abundance and community structure. Nonetheless, remarkably few manipulative experiments exclude insects for three or more years. Thus, how often, and under what conditions insects have enduring impacts remains unclear. Here we summarize the key conceptual issues and evidence from long‐term studies on the impact of insects on plant populations and communities. Models that project effects of herbivores on plant population growth, based on demographic study, suggest that insects often limit plant asymptotic population growth. However, empirical estimations of insect impacts on plant abundance based on long‐term experimental studies are few. As such, the strength and conditionality of compensatory mechanisms (such as density dependence and seedbanks) that may dampen (or exacerbate) the negative effects of insects on plant populations remains unclear. The influences of insects on plant range size and limits, invasion success and biocontrol are well‐established research areas, but are also underexplored in long‐term experiments. Insect herbivores can influence plant community structure and diversity, and change successional trajectories, often through modification of plant competitive ability. Nonetheless, effects are mostly known from mesic grasslands, take years to manifest and the extent of insect damage does not always predict their impact. The relative importance of specialist versus generalist herbivores is unclear, as is how feedbacks between plant productivity, herbivory and plant species richness contribute to community dynamics over time. Synthesis. The few existing long‐term insect suppression experiments, and many short‐term studies, suggest that insect herbivores can importantly affect plant populations and communities. Although challenging, experimental studies spanning multiple plant generations could greatly enhance our ability to develop a more predictive framework for how insect herbivores influence plant populations and communities.",
    url = "https://doi.org/10.1111/1365-2745.13996",
    doi = "10.1111/1365-2745.13996",
    openalex = "W4296186829",
    references = "doi101093oso97801988358510010001"
}

When species simultaneously compete with two or more species of competitor, higher-order interactions (HOIs) can lead to emergent properties not present when species interact in isolated pairs. To extend ecological theory to multi-competitor communities, ecologists must confront the challenges of measuring and interpreting HOIs in models of competition fit to data from nature. Such efforts are hindered by the fact that different studies use different definitions, and these definitions have unclear relationships to one another. Here, we propose a distinction between 'soft' HOIs, which identify possible interaction modification by competitors, and 'hard' HOIs, which identify interactions uniquely emerging in systems with three or more competitors. We show how these two classes of HOI differ in their motivation and interpretation, as well as the tests one uses to identify them in models fit to data. We then show how to operationalise this structure of definitions by analysing the results of a simulated competition experiment underlain by a consumer resource model. In the course of doing so, we clarify the challenges of interpreting HOIs in nature, and suggest a more precise framing of this research endeavour to catalyse further investigations.

@article{doi101111ele14022,
    author = "Kleinhesselink, Andrew R. and Kraft, Nathan J. B. and Pacala, Stephen W. and Levine, Jonathan M.",
    title = "Detecting and interpreting higher‐order interactions in ecological communities",
    year = "2022",
    journal = "Ecology Letters",
    abstract = "When species simultaneously compete with two or more species of competitor, higher-order interactions (HOIs) can lead to emergent properties not present when species interact in isolated pairs. To extend ecological theory to multi-competitor communities, ecologists must confront the challenges of measuring and interpreting HOIs in models of competition fit to data from nature. Such efforts are hindered by the fact that different studies use different definitions, and these definitions have unclear relationships to one another. Here, we propose a distinction between 'soft' HOIs, which identify possible interaction modification by competitors, and 'hard' HOIs, which identify interactions uniquely emerging in systems with three or more competitors. We show how these two classes of HOI differ in their motivation and interpretation, as well as the tests one uses to identify them in models fit to data. We then show how to operationalise this structure of definitions by analysing the results of a simulated competition experiment underlain by a consumer resource model. In the course of doing so, we clarify the challenges of interpreting HOIs in nature, and suggest a more precise framing of this research endeavour to catalyse further investigations.",
    url = "https://doi.org/10.1111/ele.14022",
    doi = "10.1111/ele.14022",
    openalex = "W4282048341",
    references = "doi101016jtree201905007"
}

Understanding the mechanisms that maintain microbial biodiversity is a critical aspiration in ecology. Past work on microbial coexistence has largely focused on species pairs, but it is unclear whether pairwise coexistence in isolation is required for coexistence in a multispecies community. To address this question, we conducted hundreds of pairwise competition experiments among the stably coexisting members of 12 different enrichment communities in vitro. To determine the outcomes of these experiments, we developed an automated image analysis pipeline to quantify species abundances. We found that competitive exclusion was the most common outcome, and it was strongly hierarchical and transitive. Because many species that coexist within a stable multispecies community fail to coexist in pairwise co-culture under identical conditions, we concluded that multispecies coexistence is an emergent phenomenon. This work highlights the importance of community context for understanding the origins of coexistence in complex ecosystems.

@article{doi101126scienceadg0727,
    author = "Chang, Chang‐Yu and Bajić, Djordje and Vila, Jean C. C. and Estrela, Sylvie and Sánchez, Álvaro",
    title = "Emergent coexistence in multispecies microbial communities",
    year = "2023",
    journal = "Science",
    abstract = "Understanding the mechanisms that maintain microbial biodiversity is a critical aspiration in ecology. Past work on microbial coexistence has largely focused on species pairs, but it is unclear whether pairwise coexistence in isolation is required for coexistence in a multispecies community. To address this question, we conducted hundreds of pairwise competition experiments among the stably coexisting members of 12 different enrichment communities in vitro. To determine the outcomes of these experiments, we developed an automated image analysis pipeline to quantify species abundances. We found that competitive exclusion was the most common outcome, and it was strongly hierarchical and transitive. Because many species that coexist within a stable multispecies community fail to coexist in pairwise co-culture under identical conditions, we concluded that multispecies coexistence is an emergent phenomenon. This work highlights the importance of community context for understanding the origins of coexistence in complex ecosystems.",
    url = "https://doi.org/10.1126/science.adg0727",
    doi = "10.1126/science.adg0727",
    openalex = "W4384926541",
    references = "doi101016jtree201905007"
}

Understanding the mechanisms driving species assembly along elevational gradients in mountains is crucial for biodiversity conservation. However, no consensus has yet been reached on how these mechanisms work. This knowledge gap is particularly pronounced in biodiversity-rich subtropical karst mountains. Integrating multidimensional biodiversity information into research in karst systems will provide new insights into community assembly. Thus, we explored multidimensional forest diversity along an elevational gradient at Jinfo mountain, a karst mountain site, assessing the relative importance of distinct ecological processes in shaping patterns of community diversity and structure. Our results show that different dimensional diversities exhibit similar elevational patterns, with higher diversity observed at low-to-mid elevations than at high elevations. The multidimensional diversity and structure were primarily controlled by climate stress and topographic filtering and were further modulated by soil nutrient limitation and interspecific competition. However, the explanatory weights of these ecological processes were inconsistent among the different dimensions of diversity. The phylogenetic structure was clustered at low and middle elevations, with over-dispersion at high elevations. This indicates that community assembly shifted from being dominated by environmental filtering to being dominated by competitive exclusion as elevation increased. In conclusion, our results demonstrate that combining multidimensional diversity and multiple ecological processes related to community assembly can enhance the understanding of diversity patterns along elevational gradients and the underlying mechanisms maintaining them in subtropical karst mountains.

@article{doi101016jpld202512007,
    author = "Zhou, Lihua and Long, Yuxiao and Hu, Siwei and Luo, Min and Mou, Wenbo and Deng, Jingwen and Jing, Lisha and Pang, Mingyue and Huang, Li and Yang, Yongchuan",
    title = "Elevational patterns of multidimensional plant diversity and community structure in a subtropical karst mountain system.",
    year = "2026",
    journal = "Plant diversity",
    abstract = "Understanding the mechanisms driving species assembly along elevational gradients in mountains is crucial for biodiversity conservation. However, no consensus has yet been reached on how these mechanisms work. This knowledge gap is particularly pronounced in biodiversity-rich subtropical karst mountains. Integrating multidimensional biodiversity information into research in karst systems will provide new insights into community assembly. Thus, we explored multidimensional forest diversity along an elevational gradient at Jinfo mountain, a karst mountain site, assessing the relative importance of distinct ecological processes in shaping patterns of community diversity and structure. Our results show that different dimensional diversities exhibit similar elevational patterns, with higher diversity observed at low-to-mid elevations than at high elevations. The multidimensional diversity and structure were primarily controlled by climate stress and topographic filtering and were further modulated by soil nutrient limitation and interspecific competition. However, the explanatory weights of these ecological processes were inconsistent among the different dimensions of diversity. The phylogenetic structure was clustered at low and middle elevations, with over-dispersion at high elevations. This indicates that community assembly shifted from being dominated by environmental filtering to being dominated by competitive exclusion as elevation increased. In conclusion, our results demonstrate that combining multidimensional diversity and multiple ecological processes related to community assembly can enhance the understanding of diversity patterns along elevational gradients and the underlying mechanisms maintaining them in subtropical karst mountains.",
    url = "https://pmc.ncbi.nlm.nih.gov/articles/PMC13071454/",
    doi = "10.1016/j.pld.2025.12.007",
    openalex = "W4417443661",
    pmcid = "PMC13071454",
    pmid = "41982282",
    references = "doi101002j153873051948tb01338x, doi1010079783319242774, doi1010160040580982900041, doi101073pnas0403588101, doi101093bioinformaticsbtn358, doi101111j001438202003tb00285x, doi101111j14610248200400701x, doi101111j160005871995tb00341x, doi101146annurevecolsys33010802150448, doi1018900712061"
}