Cooperation

Variations and Fluctuations of the Number of Individuals in Animal Species living together Get access Vito Volterra Vito Volterra Professor Translated by Miss Mary Evelyn Wells, Doctor of MathematicsRome Search for other works by this author on: Oxford Academic Google Scholar ICES Journal of Marine Science, Volume 3, Issue 1, April 1928, Pages 3–51, https://doi.org/10.1093/icesjms/3.1.3 Published: 01 April 1928

@article{doi101093icesjms313,
    author = "Volterra, Vito",
    title = "Variations and Fluctuations of the Number of Individuals in Animal Species living together",
    year = "1928",
    journal = "ICES Journal of Marine Science",
    abstract = "Variations and Fluctuations of the Number of Individuals in Animal Species living together Get access Vito Volterra Vito Volterra Professor Translated by Miss Mary Evelyn Wells, Doctor of MathematicsRome Search for other works by this author on: Oxford Academic Google Scholar ICES Journal of Marine Science, Volume 3, Issue 1, April 1928, Pages 3–51, https://doi.org/10.1093/icesjms/3.1.3 Published: 01 April 1928",
    url = "https://doi.org/10.1093/icesjms/3.1.3",
    doi = "10.1093/icesjms/3.1.3",
    openalex = "W2061011338"
}

@misc{allee1951cooperation1,
    author = "Allee, W. C",
    title = "Cooperation Among Animals with Human Implications",
    year = "1951",
    howpublished = "New York, Schuman, 233 p.; [Revised Edition of Social Life of Animals, Norton, New York, 1938]",
    note = "talkorigins\_source = {true}; raw\_reference = {Allee, W. C., 1951, Cooperation Among Animals with Human Implications: New York, Schuman, 233 p.; [Revised Edition of Social Life of Animals, Norton, New York, 1938].}"
}

@article{crossref1951allee,
    title = "Allee, W. C. Cooperation Among Animals with Human Implications. New York: Henry Schuman, Publisher, 1951. 233 p.",
    year = "1951",
    journal = "Science Education",
    url = "https://doi.org/10.1002/sce.3730350525",
    doi = "10.1002/sce.3730350525",
    number = "5",
    openalex = "W4206837436",
    pages = "301-302",
    volume = "35"
}

@article{yothers1951review,
    author = "Yothers, Lee R.",
    title = "Review: Cooperation among Animals: With Human Implications, by W. C. Allee",
    year = "1951",
    journal = "The American Biology Teacher",
    url = "https://doi.org/10.2307/4438292",
    doi = "10.2307/4438292",
    number = "6",
    openalex = "W4246039385",
    pages = "142-142",
    volume = "13"
}

@article{doi101176ajp1092158a,
    author = "Walker, Norma Ford",
    title = "Cooperation Among Animals with Human Implications",
    year = "1952",
    journal = "American Journal of Psychiatry",
    url = "https://doi.org/10.1176/ajp.109.2.158-a",
    doi = "10.1176/ajp.109.2.158-a",
    openalex = "W2050652524"
}

@article{doi1023074510320,
    author = "Nice, M. M. and Allee, W. C.",
    title = "Cooperation among Animals with Human Implications",
    year = "1952",
    journal = "Bird-Banding",
    url = "https://doi.org/10.2307/4510320",
    doi = "10.2307/4510320",
    openalex = "W1490215134"
}

@article{nice1952cooperation,
    author = "Nice, M. M. and Allee, W. C.",
    title = "Cooperation among Animals with Human Implications",
    year = "1952",
    journal = "Bird-Banding",
    url = "https://doi.org/10.2307/4510320",
    doi = "10.2307/4510320",
    number = "1",
    openalex = "W1490215134",
    pages = "49",
    volume = "23"
}

@article{walker1952cooperation,
    author = "WALKER, NORMA FORD",
    title = "Cooperation Among Animals with Human Implications",
    year = "1952",
    journal = "American Journal of Psychiatry",
    url = "https://doi.org/10.1176/ajp.109.2.158-a",
    doi = "10.1176/ajp.109.2.158-a",
    number = "2",
    openalex = "W2050652524",
    pages = "158-a-159",
    volume = "109"
}

Species distribution models (SDMs) are numerical tools that combine observations of species occurrence or abundance with environmental estimates. They are used to gain ecological and evolutionary insights and to predict distributions across landscapes,...Read More

@article{doi101146annureves02110171002341,
    author = "Janzen, Daniel H.",
    title = "Seed Predation by Animals",
    year = "1971",
    journal = "Annual Review of Ecology and Systematics",
    abstract = "Species distribution models (SDMs) are numerical tools that combine observations of species occurrence or abundance with environmental estimates. They are used to gain ecological and evolutionary insights and to predict distributions across landscapes,...Read More",
    url = "https://doi.org/10.1146/annurev.es.02.110171.002341",
    doi = "10.1146/annurev.es.02.110171.002341",
    openalex = "W2029894290",
    references = "doi101086282455, doi101111j155856461969tb03489x"
}

Discusses four related ecological topics: (1) the occurrence of tropical blackwater rivers (rich in humic acids and poor in nutrients) in areas with poor white-sand soils; (2) the poverty of animal communities that occur in forests in such areas, (3) the evolution of gregarious fruiting in the Dipterocarps of SE Asia; and (4) the persistence of certain lowland tropical tree species in forests of very low species-diversity. In the hypotheses put forward, considerable attention is given to the role of 'secondary' or 'defensive' compounds (in general, phenolics that are toxic, difficult to degrade, and hence relatively persistent) in the living vegetation and in plant and litter leachates as a factor in the formation of blackwater rivers and in the defence of plants against attack by animals. The gregarious fruiting of Dipterocarps is seen as a mechanism of escape from seed consumers that is unique to the region concerned because it has reduced animal communities.

@article{doi1023072989823,
    author = "Janzen, Daniel H.",
    title = "Tropical Blackwater Rivers, Animals, and Mast Fruiting by the Dipterocarpaceae",
    year = "1974",
    journal = "Biotropica",
    abstract = "Discusses four related ecological topics: (1) the occurrence of tropical blackwater rivers (rich in humic acids and poor in nutrients) in areas with poor white-sand soils; (2) the poverty of animal communities that occur in forests in such areas, (3) the evolution of gregarious fruiting in the Dipterocarps of SE Asia; and (4) the persistence of certain lowland tropical tree species in forests of very low species-diversity. In the hypotheses put forward, considerable attention is given to the role of 'secondary' or 'defensive' compounds (in general, phenolics that are toxic, difficult to degrade, and hence relatively persistent) in the living vegetation and in plant and litter leachates as a factor in the formation of blackwater rivers and in the defence of plants against attack by animals. The gregarious fruiting of Dipterocarps is seen as a mechanism of escape from seed consumers that is unique to the region concerned because it has reduced animal communities.",
    url = "https://doi.org/10.2307/2989823",
    doi = "10.2307/2989823",
    openalex = "W2320023580",
    references = "doi101086282907, doi1023071933565, doi1023072259009"
}

Summary Two species competition model is built up by assuming the hypothetical second order interactions in order to consider effects of exploitation on two competing fish species with non‐linear interactions. Most important characteristic of this model, compared with Lotka‐Volterra type linear competition model, is that this model can possess multiple stable equilibrium points. Therefore there is a possibility that two species keeping the equilibrium state at one stable equilibrium point will be attracted to the other stable equilibrium point after a heavy perturbation. In this model reversible change of the fishing pressure does not always results in that of the equilibrium catch. In this sence MSY concept for single species can not be extended to this model. If there are multiple stable equilibrium points, the change of the dominant fish species, catastrophic and irreversible change of each equilibrium catch may be observed when the perturbation by the exploitation is added. This phenomenon immediately reminds us of the change of the dominant fish species between Japanese common mackerel and Pacific saury in the northwest Pacific Ocean. In case of the management of two competing fish species with nonlinear interactions, the consideration on the balance between the fishing pressure for each species may be as important as the decision on the catch limit for each species. MSY level for each species based on the single‐species theory could be quite erroneous.

@article{doi101007bf02512979,
    author = "Shirakihara, Kunio and TANAKA, Syoiti",
    title = "Two fish species competition model with nonlinear interactions and equilibrium catches",
    year = "1978",
    journal = "Population Ecology",
    abstract = "Summary Two species competition model is built up by assuming the hypothetical second order interactions in order to consider effects of exploitation on two competing fish species with non‐linear interactions. Most important characteristic of this model, compared with Lotka‐Volterra type linear competition model, is that this model can possess multiple stable equilibrium points. Therefore there is a possibility that two species keeping the equilibrium state at one stable equilibrium point will be attracted to the other stable equilibrium point after a heavy perturbation. In this model reversible change of the fishing pressure does not always results in that of the equilibrium catch. In this sence MSY concept for single species can not be extended to this model. If there are multiple stable equilibrium points, the change of the dominant fish species, catastrophic and irreversible change of each equilibrium catch may be observed when the perturbation by the exploitation is added. This phenomenon immediately reminds us of the change of the dominant fish species between Japanese common mackerel and Pacific saury in the northwest Pacific Ocean. In case of the management of two competing fish species with nonlinear interactions, the consideration on the balance between the fishing pressure for each species may be as important as the decision on the catch limit for each species. MSY level for each species based on the single‐species theory could be quite erroneous.",
    url = "https://doi.org/10.1007/bf02512979",
    doi = "10.1007/bf02512979",
    openalex = "W1966020396",
    references = "doi101007bf00044132, doi101038116461b0, doi101086282272, doi101086282961, doi101093icesjms313, doi101139f57025, doi101176ajp1092158a, doi1015159780691206912, doi1023072298330, doi1023072965538, walker1952cooperation"
}

Accounting for species interactions is a key component of ecosystem-based management. Simple models of species interactions provide a framework for making qualitative comparisons and identifying critical dynamics. A review of multispecies-fisheries and marine-reserve models indicates that incorporating species interactions leads to decreased theoretical predictions for sustainable yield and harvest rates and to increased theoretical predictions for the reserve size necessary to protect populations; ontogenetic shifts in interactions also have a significant effect on multispecies model predictions. While previous models have explored negative species interactions (i.e., predation and competition), this paper presents an example marine reserve model with a positive interaction: a spiny lobster-sea urchin-red algae trophic chain where red algae facilitate lobster recruitment. Model results indicate that recruitment facilitation primarily affects the time scale of the species dynamics and the lobster spillover from reserves to harvested areas; the direction of these changes depends on the no-facilitation baseline. Overall, these models indicate the importance of incorporating species interactions into fisheries and reserve management decisions.

@article{openalexw332345030,
    author = "Baskett, Marissa L.",
    title = "Simple fisheries and marine reserve models of interacting species: An overview and example with recruitment facilitation",
    year = "2007",
    journal = "eScholarship (California Digital Library)",
    abstract = "Accounting for species interactions is a key component of ecosystem-based management. Simple models of species interactions provide a framework for making qualitative comparisons and identifying critical dynamics. A review of multispecies-fisheries and marine-reserve models indicates that incorporating species interactions leads to decreased theoretical predictions for sustainable yield and harvest rates and to increased theoretical predictions for the reserve size necessary to protect populations; ontogenetic shifts in interactions also have a significant effect on multispecies model predictions. While previous models have explored negative species interactions (i.e., predation and competition), this paper presents an example marine reserve model with a positive interaction: a spiny lobster-sea urchin-red algae trophic chain where red algae facilitate lobster recruitment. Model results indicate that recruitment facilitation primarily affects the time scale of the species dynamics and the lobster spillover from reserves to harvested areas; the direction of these changes depends on the no-facilitation baseline. Overall, these models indicate the importance of incorporating species interactions into fisheries and reserve management decisions.",
    openalex = "W332345030",
    references = "doi101007bf02512979"
}

We analyse an epidemiological model of competing strains of pathogens and hence differences in transmission for first versus secondary infection due to interaction of the strains with previously aquired immunities, as has been described for dengue fever, is known as antibody dependent enhancement (ADE). These models show a rich variety of dynamics through bifurcations up to deterministic chaos. Including temporary cross-immunity even enlarges the parameter range of such chaotic attractors, and also gives rise to various coexisting attractors, which are difficult to identify by standard numerical bifurcation programs using continuation methods. A combination of techniques, including classical bifurcation plots and Lyapunov exponent spectra, has to be applied in comparison to get further insight into such dynamical structures. Here we present for the first time multi-parameter studies in a range of biologically plausible values for dengue. The multi-strain interaction with the immune system is expected to have implications for the epidemiology of other diseases also.

@article{doi10108000207160902783532,
    author = "Aguiar, Maíra and Stollenwerk, Nico and Kooi, Bob W.",
    title = "Torus bifurcations, isolas and chaotic attractors in a simple dengue fever model with ADE and temporary cross immunity",
    year = "2009",
    journal = "International Journal of Computer Mathematics",
    abstract = "We analyse an epidemiological model of competing strains of pathogens and hence differences in transmission for first versus secondary infection due to interaction of the strains with previously aquired immunities, as has been described for dengue fever, is known as antibody dependent enhancement (ADE). These models show a rich variety of dynamics through bifurcations up to deterministic chaos. Including temporary cross-immunity even enlarges the parameter range of such chaotic attractors, and also gives rise to various coexisting attractors, which are difficult to identify by standard numerical bifurcation programs using continuation methods. A combination of techniques, including classical bifurcation plots and Lyapunov exponent spectra, has to be applied in comparison to get further insight into such dynamical structures. Here we present for the first time multi-parameter studies in a range of biologically plausible values for dengue. The multi-strain interaction with the immune system is expected to have implications for the epidemiology of other diseases also.",
    url = "https://doi.org/10.1080/00207160902783532",
    doi = "10.1080/00207160902783532",
    openalex = "W2148427710",
    references = "doi101007s0028500302560"
}

Resource ratio theory predicts that two species may coexist in the presence of two limiting nutrients provided that each species is limited by the resource it is least able to deplete. We modify this classical competition model to allow interspecific cooperation through trading. We show that resource trade expands the realm of stable coexistence, and that optimal trading partners competitively invade and exclude any other trading or non-trading strategy. We show that natural selection favours evolution towards establishment of a trading relationship so long as partners can establish long-term associations even though cooperation may result in a decrease in abundance of one species. This theory substantively expands traditional applications of resource competition models and suggests additional empirical experimentation.

@article{doi101111j14610248200901431x,
    author = "de Mazancourt, Claire and Schwartz, Mark W.",
    title = "A resource ratio theory of cooperation",
    year = "2010",
    journal = "Ecology Letters",
    abstract = "Resource ratio theory predicts that two species may coexist in the presence of two limiting nutrients provided that each species is limited by the resource it is least able to deplete. We modify this classical competition model to allow interspecific cooperation through trading. We show that resource trade expands the realm of stable coexistence, and that optimal trading partners competitively invade and exclude any other trading or non-trading strategy. We show that natural selection favours evolution towards establishment of a trading relationship so long as partners can establish long-term associations even though cooperation may result in a decrease in abundance of one species. This theory substantively expands traditional applications of resource competition models and suggests additional empirical experimentation.",
    url = "https://doi.org/10.1111/j.1461-0248.2009.01431.x",
    doi = "10.1111/j.1461-0248.2009.01431.x",
    openalex = "W2058458736",
    references = "doi1010160304380085900067"
}

Collinearity refers to the non independence of predictor variables, usually in a regression‐type analysis. It is a common feature of any descriptive ecological data set and can be a problem for parameter estimation because it inflates the variance of regression parameters and hence potentially leads to the wrong identification of relevant predictors in a statistical model. Collinearity is a severe problem when a model is trained on data from one region or time, and predicted to another with a different or unknown structure of collinearity. To demonstrate the reach of the problem of collinearity in ecology, we show how relationships among predictors differ between biomes, change over spatial scales and through time. Across disciplines, different approaches to addressing collinearity problems have been developed, ranging from clustering of predictors, threshold‐based pre‐selection, through latent variable methods, to shrinkage and regularisation. Using simulated data with five predictor‐response relationships of increasing complexity and eight levels of collinearity we compared ways to address collinearity with standard multiple regression and machine‐learning approaches. We assessed the performance of each approach by testing its impact on prediction to new data. In the extreme, we tested whether the methods were able to identify the true underlying relationship in a training dataset with strong collinearity by evaluating its performance on a test dataset without any collinearity. We found that methods specifically designed for collinearity, such as latent variable methods and tree based models, did not outperform the traditional GLM and threshold‐based pre‐selection. Our results highlight the value of GLM in combination with penalised methods (particularly ridge) and threshold‐based pre‐selection when omitted variables are considered in the final interpretation. However, all approaches tested yielded degraded predictions under change in collinearity structure and the ‘folk lore’‐thresholds of correlation coefficients between predictor variables of |r| >0.7 was an appropriate indicator for when collinearity begins to severely distort model estimation and subsequent prediction. The use of ecological understanding of the system in pre‐analysis variable selection and the choice of the least sensitive statistical approaches reduce the problems of collinearity, but cannot ultimately solve them.

@article{doi101111j16000587201207348x,
    author = "Dormann, Carsten F. and Elith, Jane and Bacher, Sven and Buchmann, Carsten M. and Carl, Gudrun and Carré, Gabriel and Márquez, Jaime and Gruber, Bernd and Lafourcade, Bruno and Leitão, Pedro J. and Münkemüller, Tamara and McClean, Colin J. and Osborne, Patrick E. and Reineking, Björn and Schröder, Boris and Skidmore, Andrew K. and Zurell, Damaris and Lautenbach, Sven",
    title = "Collinearity: a review of methods to deal with it and a simulation study evaluating their performance",
    year = "2012",
    journal = "Ecography",
    abstract = "Collinearity refers to the non independence of predictor variables, usually in a regression‐type analysis. It is a common feature of any descriptive ecological data set and can be a problem for parameter estimation because it inflates the variance of regression parameters and hence potentially leads to the wrong identification of relevant predictors in a statistical model. Collinearity is a severe problem when a model is trained on data from one region or time, and predicted to another with a different or unknown structure of collinearity. To demonstrate the reach of the problem of collinearity in ecology, we show how relationships among predictors differ between biomes, change over spatial scales and through time. Across disciplines, different approaches to addressing collinearity problems have been developed, ranging from clustering of predictors, threshold‐based pre‐selection, through latent variable methods, to shrinkage and regularisation. Using simulated data with five predictor‐response relationships of increasing complexity and eight levels of collinearity we compared ways to address collinearity with standard multiple regression and machine‐learning approaches. We assessed the performance of each approach by testing its impact on prediction to new data. In the extreme, we tested whether the methods were able to identify the true underlying relationship in a training dataset with strong collinearity by evaluating its performance on a test dataset without any collinearity. We found that methods specifically designed for collinearity, such as latent variable methods and tree based models, did not outperform the traditional GLM and threshold‐based pre‐selection. Our results highlight the value of GLM in combination with penalised methods (particularly ridge) and threshold‐based pre‐selection when omitted variables are considered in the final interpretation. However, all approaches tested yielded degraded predictions under change in collinearity structure and the ‘folk lore’‐thresholds of correlation coefficients between predictor variables of |r| >0.7 was an appropriate indicator for when collinearity begins to severely distort model estimation and subsequent prediction. The use of ecological understanding of the system in pre‐analysis variable selection and the choice of the least sensitive statistical approaches reduce the problems of collinearity, but cannot ultimately solve them.",
    url = "https://doi.org/10.1111/j.1600-0587.2012.07348.x",
    doi = "10.1111/j.1600-0587.2012.07348.x",
    openalex = "W1998025025",
    references = "doi10100797814471034794, doi101023a1010933404324, doi101111j14610248200801277x, doi101111j14679868200500503x, doi101111j2041210x200900001x, doi1012019781420010404, openalexw2097360283"
}

We consider the existence of at least three positive solutions of a nonlinear first order problem with a nonlinear nonlocal boundary condition given by

@article{doi107494opmath201636169,
    author = "Padhi, Seshadev and Pati, Smita and Hota, D. K.",
    title = "Positive solutions of boundary value problems with nonlinear nonlocal boundary conditions",
    year = "2015",
    journal = "Opuscula Mathematica",
    abstract = "We consider the existence of at least three positive solutions of a nonlinear first order problem with a nonlinear nonlocal boundary condition given by",
    url = "https://doi.org/10.7494/opmath.2016.36.1.69",
    doi = "10.7494/opmath.2016.36.1.69",
    openalex = "W1641159214",
    references = "doi101016jnonrwa201107044"
}

In this paper, we design, analyze and numerically validate energy dissipating finite volume schemes for a competition-mutation equation with a gradient flow structure.The model describes the evolution of a population structured with respect to a continuous trait.Both semi-discrete and fully discrete schemes are demonstrated to satisfy the two desired properties: positivity of numerical solutions and energy dissipation.These ensure that the positive steady state is asymptotically stable.Moreover, the discrete steady state is proven to be the same as the minimizer of a discrete energy function.As a comparison, the positive steady state can also be produced by a nonlinear programming solver.Finally, a series of numerical tests is provided to demonstrate both accuracy and the energy dissipation property of the numerical schemes.The numerical solutions of the model with small mutation are shown to be close to those of the corresponding model with linear competition.

@article{doi101051m2an2016058,
    author = "Cai, Wenli and Liu, Hailiang",
    title = "A finite volume method for nonlocal competition-mutation equations with a gradient flow structure",
    year = "2016",
    journal = "ESAIM Mathematical Modelling and Numerical Analysis",
    abstract = "In this paper, we design, analyze and numerically validate energy dissipating finite volume schemes for a competition-mutation equation with a gradient flow structure.The model describes the evolution of a population structured with respect to a continuous trait.Both semi-discrete and fully discrete schemes are demonstrated to satisfy the two desired properties: positivity of numerical solutions and energy dissipation.These ensure that the positive steady state is asymptotically stable.Moreover, the discrete steady state is proven to be the same as the minimizer of a discrete energy function.As a comparison, the positive steady state can also be produced by a nonlinear programming solver.Finally, a series of numerical tests is provided to demonstrate both accuracy and the energy dissipation property of the numerical schemes.The numerical solutions of the model with small mutation are shown to be close to those of the corresponding model with linear competition.",
    url = "https://doi.org/10.1051/m2an/2016058",
    doi = "10.1051/m2an/2016058",
    openalex = "W2534102177",
    references = "doi101007bf02512979"
}

In this paper, we are interested in an integro-differential model with a non-linear competition term that describes the evolution of a population structured with respect to a continuous trait. Under some assumptions, the steady solution is shown unique and strictly positive, and also globally stable. The exponential convergence rate to the steady state is also established.

@article{doi10108813616544aa85da,
    author = "Jabin, Pierre‐Emmanuel and Liu, Hailiang",
    title = "On a non-local selection–mutation model with a gradient flow structure",
    year = "2017",
    journal = "Nonlinearity",
    abstract = "In this paper, we are interested in an integro-differential model with a non-linear competition term that describes the evolution of a population structured with respect to a continuous trait. Under some assumptions, the steady solution is shown unique and strictly positive, and also globally stable. The exponential convergence rate to the steady state is also established.",
    url = "https://doi.org/10.1088/1361-6544/aa85da",
    doi = "10.1088/1361-6544/aa85da",
    openalex = "W2765995902",
    references = "doi101007bf02512979"
}

We consider a predator--prey system with nonmonotonic functional response and a hyperbolic type of mate-finding Allee effect on prey. A detailed mathematical analysis of the system, including the stability and a series of bifurcations (a saddle-node, a Hopf, and a Bogdanov--Takens bifurcation), has been given. The mathematical results show that the system is highly sensitive to the parameters and initial status. It exhibits a stable limit cycle, or different types of heteroclinic curves, or a homoclinic loop when parameters take suitable values.

@article{doi103906mat14118,
    author = "Wu, Ruiwen and Liu, Xiuxiang",
    title = "Dynamics of a predator-prey system with a mate-finding Allee effect on prey",
    year = "2017",
    journal = "TURKISH JOURNAL OF MATHEMATICS",
    abstract = "We consider a predator--prey system with nonmonotonic functional response and a hyperbolic type of mate-finding Allee effect on prey. A detailed mathematical analysis of the system, including the stability and a series of bifurcations (a saddle-node, a Hopf, and a Bogdanov--Takens bifurcation), has been given. The mathematical results show that the system is highly sensitive to the parameters and initial status. It exhibits a stable limit cycle, or different types of heteroclinic curves, or a homoclinic loop when parameters take suitable values.",
    url = "https://doi.org/10.3906/mat-1411-8",
    doi = "10.3906/mat-1411-8",
    openalex = "W2618798731",
    references = "doi101016jnonrwa201107044"
}

Models of the spatial distribution of animals provide useful tools to help ecologists quantify species-environment relationships, and they are increasingly being used to help determine the impacts of climate and habitat changes on species. While high-quality survey-style data with known effort are sometimes available, often researchers have multiple datasets of varying quality and type. In particular, collections of sightings made by citizen scientists are becoming increasingly common, with no information typically provided on their observer effort. Many standard modelling approaches ignore observer effort completely which can severely bias estimates of an animal’s distribution. Combining sightings data from observers who followed different protocols is challenging. Any differences in observer skill, spatial effort and the detectability of the animals across space all need to be accounted for. To achieve this, we build upon the recent advancements made in integrative species distribution models and present a novel marked spatiotemporal point process framework for estimating the utilization distribution (UD) of the individuals of a highly mobile species. We show that, in certain settings, we can also use the framework to combine the UDs from the sampled individuals to estimate the species’ distribution. We combine the empirical results from a simulation study with the implications outlined in a causal directed acyclic graph to identify the necessary assumptions required for our framework to control for observer effort when it is unknown. We then apply our framework to combine multiple datasets collected on the endangered Southern Resident Killer Whales to estimate their monthly effort-corrected space-use.

@article{doi10121421aoas1472,
    author = "Watson, Joe and Joy, Ruth and Tollit, Dominic and Thornton, Sheila J. and Auger‐Méthé, Marie",
    title = "Estimating animal utilization distributions from multiple data types: A joint spatiotemporal point process framework",
    year = "2021",
    journal = "The Annals of Applied Statistics",
    abstract = "Models of the spatial distribution of animals provide useful tools to help ecologists quantify species-environment relationships, and they are increasingly being used to help determine the impacts of climate and habitat changes on species. While high-quality survey-style data with known effort are sometimes available, often researchers have multiple datasets of varying quality and type. In particular, collections of sightings made by citizen scientists are becoming increasingly common, with no information typically provided on their observer effort. Many standard modelling approaches ignore observer effort completely which can severely bias estimates of an animal’s distribution. Combining sightings data from observers who followed different protocols is challenging. Any differences in observer skill, spatial effort and the detectability of the animals across space all need to be accounted for. To achieve this, we build upon the recent advancements made in integrative species distribution models and present a novel marked spatiotemporal point process framework for estimating the utilization distribution (UD) of the individuals of a highly mobile species. We show that, in certain settings, we can also use the framework to combine the UDs from the sampled individuals to estimate the species’ distribution. We combine the empirical results from a simulation study with the implications outlined in a causal directed acyclic graph to identify the necessary assumptions required for our framework to control for observer effort when it is unknown. We then apply our framework to combine multiple datasets collected on the endangered Southern Resident Killer Whales to estimate their monthly effort-corrected space-use.",
    url = "https://doi.org/10.1214/21-aoas1472",
    doi = "10.1214/21-aoas1472",
    openalex = "W3082630804",
    references = "doi10249262020081320"
}

A nonautonomous logistic population model with a feature of an Allee threshold has been investigated in a periodically fluctuating environment. A slow periodicity of the harvesting effort was considered and may arise in response to relatively slow fluctuations of the environment. This assumption permits obtaining the analytical approximate solutions of such model using the perturbation approach based on the slow variation. Thus, the analytical expressions of the population evolution in the situation of subcritical and the supercritical harvesting were obtained and discussed in the framework of the Allee effect. Since the exact solution was not available due to the nonlinearity of the system, the numerical computation was considered to validate our analytical approximation. The comparison between the two methods showed a remarkable agreement as the time progressed, while such agreement fell off when the time was close to the initial density. Moreover, in the absence of the periodicity of the harvesting term, the expressions of the population evolution reduced to the exact solutions but in implicit forms. The finding results were appropriate for a wide range of parameter values, which lead to avoiding extensive recalculations while displaying the population behavior.

@article{doi103934math2024430,
    author = "Alharbi, Fahad M.",
    title = "Harvesting a population model with Allee effect in a periodically varying environment",
    year = "2024",
    journal = "AIMS Mathematics",
    abstract = "A nonautonomous logistic population model with a feature of an Allee threshold has been investigated in a periodically fluctuating environment. A slow periodicity of the harvesting effort was considered and may arise in response to relatively slow fluctuations of the environment. This assumption permits obtaining the analytical approximate solutions of such model using the perturbation approach based on the slow variation. Thus, the analytical expressions of the population evolution in the situation of subcritical and the supercritical harvesting were obtained and discussed in the framework of the Allee effect. Since the exact solution was not available due to the nonlinearity of the system, the numerical computation was considered to validate our analytical approximation. The comparison between the two methods showed a remarkable agreement as the time progressed, while such agreement fell off when the time was close to the initial density. Moreover, in the absence of the periodicity of the harvesting term, the expressions of the population evolution reduced to the exact solutions but in implicit forms. The finding results were appropriate for a wide range of parameter values, which lead to avoiding extensive recalculations while displaying the population behavior.",
    url = "https://doi.org/10.3934/math.2024430",
    doi = "10.3934/math.2024430",
    openalex = "W4392400231",
    references = "doi101016jnonrwa201107044"
}

Abstract Dispersal is a fundamental life-history component of species, affecting ecological and evolutionary processes. Sex-specific patterns of dispersal may arise to alleviate the effects of inbreeding, kin competition, or limited resources, and are common in many taxa. We examined sex-biased dispersal of Fratercula arctica (Atlantic Puffin) hatched on Machias Seal Island to 4 breeding colonies in the Gulf of Maine using mark–recapture data. We evaluated if one sex disperses more frequently, if there is a sex bias in the breeding colony choice of dispersed F. arctica, and if sex interacts with other individual factors to influence dispersal. There was no significant difference in the frequency that female and male F. arctica dispersed, or the breeding colony they dispersed to. However, we found that with increasing fledge date, female F. arctica were more likely to disperse and males were less likely to disperse, with this relationship being weaker for male F. arctica. Fledge date was unrelated to body condition, and so other rearing conditions or broader environmental constraints reflected by fledge date may be more influential for females when making dispersal decisions. Our results suggest the smaller Gulf of Maine colonies receive a balanced sex ratio of immigrants from Machias Seal Island, which improves our understanding of metapopulation dynamics. The frequency of dispersal differed among years, and was not fully explained by sex or fledge date, highlighting the need for further research to understand which factors influence F. arctica dispersal.

@article{doi101093ornithologyukaf073,
    author = "Carvey, Quinn B. and Diamond, Antony W and Lyons, Donald E and Major, Heather",
    title = "Sex interacts with fledge date to influence dispersal probability in Fratercula arctica (Atlantic Puffin)",
    year = "2025",
    journal = "The Auk",
    abstract = "Abstract Dispersal is a fundamental life-history component of species, affecting ecological and evolutionary processes. Sex-specific patterns of dispersal may arise to alleviate the effects of inbreeding, kin competition, or limited resources, and are common in many taxa. We examined sex-biased dispersal of Fratercula arctica (Atlantic Puffin) hatched on Machias Seal Island to 4 breeding colonies in the Gulf of Maine using mark–recapture data. We evaluated if one sex disperses more frequently, if there is a sex bias in the breeding colony choice of dispersed F. arctica, and if sex interacts with other individual factors to influence dispersal. There was no significant difference in the frequency that female and male F. arctica dispersed, or the breeding colony they dispersed to. However, we found that with increasing fledge date, female F. arctica were more likely to disperse and males were less likely to disperse, with this relationship being weaker for male F. arctica. Fledge date was unrelated to body condition, and so other rearing conditions or broader environmental constraints reflected by fledge date may be more influential for females when making dispersal decisions. Our results suggest the smaller Gulf of Maine colonies receive a balanced sex ratio of immigrants from Machias Seal Island, which improves our understanding of metapopulation dynamics. The frequency of dispersal differed among years, and was not fully explained by sex or fledge date, highlighting the need for further research to understand which factors influence F. arctica dispersal.",
    url = "https://doi.org/10.1093/ornithology/ukaf073",
    doi = "10.1093/ornithology/ukaf073",
    openalex = "W7117249024",
    references = "doi101007s10980022015096"
}

Dispersal is a fundamental process driving many ecological patterns. During transfer, species often make large-scale displacements resulting in significant energy losses with implications for fitness and survival, however generalising these losses across different taxonomic groups is challenging. We developed a bioenergetic dispersal model based on fundamental processes derived from species traits. By balancing energy storage and energy loss during active dispersal, our mechanistic model can quantify energy expenditures depending on landscape configuration and the species in focus. Moreover, it can be used to predict the maximum dispersal capacity of animals, which we compare with recorded maximum dispersal distances (n = 1571). Due to its foundation in bioenergetics it can easily be integrated into various ecological models, such as food-web and meta-community models. Furthermore, as dispersal is integral to ecological research, the quantification of dispersal capacities provides valuable insight into landscape connectivity, species persistence, and distribution patterns with implications for conservation research.

@article{doi101111ele70085,
    author = "Wilkinson, Caitlin and Brose, Ulrich and Dyer, Alexander and Hirt, Myriam R. and Ryser, Remo",
    title = "A Mechanistic Approach to Animal Dispersal—Quantifying Energetics and Maximum Distances",
    year = "2025",
    journal = "Ecology Letters",
    abstract = "Dispersal is a fundamental process driving many ecological patterns. During transfer, species often make large-scale displacements resulting in significant energy losses with implications for fitness and survival, however generalising these losses across different taxonomic groups is challenging. We developed a bioenergetic dispersal model based on fundamental processes derived from species traits. By balancing energy storage and energy loss during active dispersal, our mechanistic model can quantify energy expenditures depending on landscape configuration and the species in focus. Moreover, it can be used to predict the maximum dispersal capacity of animals, which we compare with recorded maximum dispersal distances (n = 1571). Due to its foundation in bioenergetics it can easily be integrated into various ecological models, such as food-web and meta-community models. Furthermore, as dispersal is integral to ecological research, the quantification of dispersal capacities provides valuable insight into landscape connectivity, species persistence, and distribution patterns with implications for conservation research.",
    url = "https://doi.org/10.1111/ele.70085",
    doi = "10.1111/ele.70085",
    openalex = "W4407777456",
    references = "doi101007s10980022015096"
}