Resource management

@article{cody1968on,
    author = "Cody, Martin L.",
    title = "On the Methods of Resource Division in Grassland Bird Communities",
    year = "1968",
    journal = "The American Naturalist",
    url = "https://doi.org/10.1086/282531",
    doi = "10.1086/282531",
    number = "924",
    pages = "107-147",
    volume = "102"
}

@misc{cody1968on2,
    author = "Cody, M. L",
    title = "On the methods of resource division in grassland bird communities",
    year = "1968",
    howpublished = "American Naturalist, v. 102, p. 107-147",
    note = "talkorigins\_source = {true}; raw\_reference = {Cody, M. L., 1968, On the methods of resource division in grassland bird communities: American Naturalist, v. 102, p. 107-147.}"
}

@misc{cloud1969resources1,
    author = "Cloud, P. E. and Jr",
    title = "Resources and Man",
    year = "1969",
    howpublished = "San Francisco, Freeman",
    note = "talkorigins\_source = {true}; raw\_reference = {Cloud, P. E., Jr., 1969, Resources and Man: San Francisco, Freeman.}"
}

@article{grzybowski1982population,
    author = "Grzybowski, Joseph A.",
    title = "Population Structure in Grassland Bird Communities during Winter",
    year = "1982",
    journal = "The Condor",
    url = "https://doi.org/10.2307/1367657",
    doi = "10.2307/1367657",
    number = "2",
    pages = "137",
    volume = "84"
}

The influence of area and vegetation structure on breeding bird communities associated with 24 Illinois grassland fragments (0.5—600 ha) was studied between 1987 and 1989 to document the effects of habitat fragmentation in a severely fragmented midwestern landscape. Fragment area strongly influenced bird communities within grasslands and accounted for a high percentage of the variation in mean breeding bird species richness among fragments (R 2 = 0.84). Breeding bird species richness patterns within 4.5—ha subsections of these grasslands also significantly increased with fragment size. Eight of the 15 (53%) most common bird species had distributions among fragments that were significantly influenced by habitat area, whereas six species (40%) had distributions within fragments that were significantly influenced by vegetation structure only. The Dickcissel (Spiza americana) was the only species with a distribution within fragments that was not significantly associated with either habitat area or vegetation structure. Four groups of birds were identified by an analysis of habitat area and vegetation structure preferences of individual species: area—sensitive species (5 species), edge species (3), vegetation—restricted species (6), and the Dickcissel. Estimates of minimal area requirements for the five area—sensitive species ranged from 5 to 55 ha. Discriminant analyses of habitat suitability within fragments suggests that the absence of area—sensitive grassland bird species form some small fragments may result, in part, from limited habitat availability. All five area—sensitive species, however, also regularly avoided structurally suitable habitat on small grassland fragments. As a result of the considerable extent to which native and, more recently, agricultural grasslands have declined in the Midwest, habitat fragmentation is likely to have caused midwestern grassland bird declines, especially for area—sensitive species.

@article{herkert1994the,
    author = "Herkert, James R.",
    title = "The Effects of Habitat Fragmentation on Midwestern Grassland Bird Communities",
    year = "1994",
    journal = "Ecological Applications",
    abstract = "The influence of area and vegetation structure on breeding bird communities associated with 24 Illinois grassland fragments (0.5—600 ha) was studied between 1987 and 1989 to document the effects of habitat fragmentation in a severely fragmented midwestern landscape. Fragment area strongly influenced bird communities within grasslands and accounted for a high percentage of the variation in mean breeding bird species richness among fragments (R 2 = 0.84). Breeding bird species richness patterns within 4.5—ha subsections of these grasslands also significantly increased with fragment size. Eight of the 15 (53\%) most common bird species had distributions among fragments that were significantly influenced by habitat area, whereas six species (40\%) had distributions within fragments that were significantly influenced by vegetation structure only. The Dickcissel (Spiza americana) was the only species with a distribution within fragments that was not significantly associated with either habitat area or vegetation structure. Four groups of birds were identified by an analysis of habitat area and vegetation structure preferences of individual species: area—sensitive species (5 species), edge species (3), vegetation—restricted species (6), and the Dickcissel. Estimates of minimal area requirements for the five area—sensitive species ranged from 5 to 55 ha. Discriminant analyses of habitat suitability within fragments suggests that the absence of area—sensitive grassland bird species form some small fragments may result, in part, from limited habitat availability. All five area—sensitive species, however, also regularly avoided structurally suitable habitat on small grassland fragments. As a result of the considerable extent to which native and, more recently, agricultural grasslands have declined in the Midwest, habitat fragmentation is likely to have caused midwestern grassland bird declines, especially for area—sensitive species.",
    url = "https://doi.org/10.2307/1941950",
    doi = "10.2307/1941950",
    number = "3",
    pages = "461-471",
    volume = "4"
}

@incollection{johnson2002grassland,
    author = "Johnson, Douglas and Browder, Sharon and Winter, Maiken",
    title = "Grassland Bird Communities and Environmental Health",
    year = "2002",
    booktitle = "Managing for Healthy Ecosystems",
    url = "https://doi.org/10.1201/9781420032130.ch63",
    doi = "10.1201/9781420032130.ch63"
}

Extensive habitat loss and changing agricultural practices have caused widespread declines in grassland birds throughout North America. The Flint Hills of Kansas and Oklahoma--the largest remaining tallgrass prairie--is important for grassland bird conservation despite supporting a major cattle industry. In 2004 and 2005, we assessed the community, population, and demographic responses of grassland birds to the predominant management practices (grazing, burning, and haying) of the region, including grasslands restored under the Conservation Reserve Program (CRP). We targeted 3 species at the core of this avian community: the Dickcissel (Spiza americana), Grasshopper Sparrow (Ammodramus savannarum), and Eastern Meadowlark (Sturnella magna). Bird diversity was higher in native prairie hayfields and grazed pastures than CRP fields, which were dominated by Dickcissels. Although Dickcissel density was highest in CRP, their nest success was highest and nest parasitism by Brown-headed Cowbirds (Moluthrus ater) lowest in unburned hayfields (in 2004). Conversely, Grasshopper Sparrow density was highest in grazed pastures, but their nest success was lowest in these pastures and highest in burned hayfields, where cowbird parasitism was also lowest (in 2004). Management did not influence density and nest survival of Eastern Meadowlarks, which were uniformly low across the region. Nest success was extremely low (5-12%) for all 3 species in 2005, perhaps because of a record spring drought. Although the CRP has benefited grassland birds in agricultural landscapes, these areas may have lower habitat value in the context of native prairie. Hayfields may provide beneficial habitat for some grassland birds in the Flint Hills because they are mowed later in the breeding season than elsewhere in the Midwest. Widespread grazing and annual burning have homogenized habitat-and thus grassland-bird responses-across the Flint Hills. Diversification of management practices could increase habitat heterogeneity and enhance the conservation potential of the Flint Hills for grassland birds.

@article{doi101111j15231739200801118x,
    author = "Rahmig, Corina J and Jensen, William E and With, Kimberly A",
    title = "Grassland bird responses to land management in the largest remaining tallgrass prairie.",
    year = "2009",
    journal = "Conservation biology: the journal of the Society for Conservation Biology",
    abstract = "Extensive habitat loss and changing agricultural practices have caused widespread declines in grassland birds throughout North America. The Flint Hills of Kansas and Oklahoma--the largest remaining tallgrass prairie--is important for grassland bird conservation despite supporting a major cattle industry. In 2004 and 2005, we assessed the community, population, and demographic responses of grassland birds to the predominant management practices (grazing, burning, and haying) of the region, including grasslands restored under the Conservation Reserve Program (CRP). We targeted 3 species at the core of this avian community: the Dickcissel (Spiza americana), Grasshopper Sparrow (Ammodramus savannarum), and Eastern Meadowlark (Sturnella magna). Bird diversity was higher in native prairie hayfields and grazed pastures than CRP fields, which were dominated by Dickcissels. Although Dickcissel density was highest in CRP, their nest success was highest and nest parasitism by Brown-headed Cowbirds (Moluthrus ater) lowest in unburned hayfields (in 2004). Conversely, Grasshopper Sparrow density was highest in grazed pastures, but their nest success was lowest in these pastures and highest in burned hayfields, where cowbird parasitism was also lowest (in 2004). Management did not influence density and nest survival of Eastern Meadowlarks, which were uniformly low across the region. Nest success was extremely low (5-12\%) for all 3 species in 2005, perhaps because of a record spring drought. Although the CRP has benefited grassland birds in agricultural landscapes, these areas may have lower habitat value in the context of native prairie. Hayfields may provide beneficial habitat for some grassland birds in the Flint Hills because they are mowed later in the breeding season than elsewhere in the Midwest. Widespread grazing and annual burning have homogenized habitat-and thus grassland-bird responses-across the Flint Hills. Diversification of management practices could increase habitat heterogeneity and enhance the conservation potential of the Flint Hills for grassland birds.",
    url = "https://pubmed.ncbi.nlm.nih.gov/19040653/",
    doi = "10.1111/j.1523-1739.2008.01118.x",
    pmid = "19040653"
}

@article{bazzi2014habitat,
    author = "Bazzi, Gaia and Foglini, Claudio and Brambilla, Mattia and Saino, Nicola and Rubolini, Diego",
    title = "Habitat management effects on Prealpine grassland bird communities",
    year = "2014",
    journal = "Italian Journal of Zoology",
    url = "https://doi.org/10.1080/11250003.2014.983566",
    doi = "10.1080/11250003.2014.983566",
    pages = "1-11"
}

Birds that depend on grassland and successional‐scrub vegetation communities are experiencing a greater decline than any other avian assemblage in North America. Habitat loss and degradation on breeding and wintering grounds are among the leading causes of these declines. We used public and private lands in northern Virginia, USA, to explore benefits of grassland management and associated field structure on supporting overwintering bird species from 2013 to 2016. Specifically, we used non‐metric multidimensional scaling and multispecies occupancy models to compare species richness and habitat associations of grassland‐obligate and successional‐scrub species during winter in fields comprised of native warm‐season grasses (WSG) or non‐native cool‐season grasses (CSG) that were managed at different times of the year. Results demonstrated positive correlations of grassland‐obligate species with decreased vegetation structure and a higher percentage of grass cover, whereas successional‐scrub species positively correlated with increased vegetation structure and height and increased percentages of woody stems, forb cover, and bare ground. Fields of WSG supported higher estimated total and target species richness compared to fields of CSG. Estimated species richness was also influenced by management timing, with fields managed during the previous winter or left unmanaged exhibiting higher estimated richness than fields managed in summer or fall. Warm‐season grass fields managed in the previous winter or left unmanaged had higher estimated species richness than any other treatment group. This study identifies important winter habitat associations (e.g., vegetation height and field openness) with species abundance and richness and can be used to make inferences about optimal management practices for overwintering avian species in eastern grasslands of North America. © 2019 The Authors. Journal of Wildlife Management Published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.

@article{johnson2019effects,
    author = "Johnson, Amy E. M. and Sillett, T. Scott and Luther, David and Herrmann, Valentine and Akre, Thomas A. and McShea, William J.",
    title = "Effects of grassland management on overwintering bird communities",
    year = "2019",
    journal = "The Journal of Wildlife Management",
    abstract = "Birds that depend on grassland and successional‐scrub vegetation communities are experiencing a greater decline than any other avian assemblage in North America. Habitat loss and degradation on breeding and wintering grounds are among the leading causes of these declines. We used public and private lands in northern Virginia, USA, to explore benefits of grassland management and associated field structure on supporting overwintering bird species from 2013 to 2016. Specifically, we used non‐metric multidimensional scaling and multispecies occupancy models to compare species richness and habitat associations of grassland‐obligate and successional‐scrub species during winter in fields comprised of native warm‐season grasses (WSG) or non‐native cool‐season grasses (CSG) that were managed at different times of the year. Results demonstrated positive correlations of grassland‐obligate species with decreased vegetation structure and a higher percentage of grass cover, whereas successional‐scrub species positively correlated with increased vegetation structure and height and increased percentages of woody stems, forb cover, and bare ground. Fields of WSG supported higher estimated total and target species richness compared to fields of CSG. Estimated species richness was also influenced by management timing, with fields managed during the previous winter or left unmanaged exhibiting higher estimated richness than fields managed in summer or fall. Warm‐season grass fields managed in the previous winter or left unmanaged had higher estimated species richness than any other treatment group. This study identifies important winter habitat associations (e.g., vegetation height and field openness) with species abundance and richness and can be used to make inferences about optimal management practices for overwintering avian species in eastern grasslands of North America. © 2019 The Authors. Journal of Wildlife Management Published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.",
    url = "https://doi.org/10.1002/jwmg.21730",
    doi = "10.1002/jwmg.21730",
    number = "7",
    pages = "1515-1526",
    volume = "83"
}

One of the most pressing questions in ecology and conservation centers on disentangling the relative impacts of concurrent global change drivers, climate and land-use/land-cover (LULC), on biodiversity. Yet studies that evaluate the effects of both drivers on species' winter distributions remain scarce, hampering our ability to develop full-annual-cycle conservation strategies. Additionally, understanding how groups of species differentially respond to climate versus LULC change is vital for efforts to enhance bird community resilience to future environmental change. We analyzed long-term changes in winter occurrence of 89 species across nine bird groups over a 90-year period within the eastern United States using Audubon Christmas Bird Count (CBC) data. We estimated variation in occurrence probability of each group as a function of spatial and temporal variation in winter climate (minimum temperature, cumulative precipitation) and LULC (proportion of group-specific and anthropogenic habitats within CBC circle). We reveal that spatial variation in bird occurrence probability was consistently explained by climate across all nine species groups. Conversely, LULC change explained more than twice the temporal variation (i.e., decadal changes) in bird occurrence probability than climate change on average across groups. This pattern was largely driven by habitat-constrained species (e.g., grassland birds, waterbirds), whereas decadal changes in occurrence probabilities of habitat-unconstrained species (e.g., forest passerines, mixed habitat birds) were equally explained by both climate and LULC changes over the last century. We conclude that climate has generally governed the winter occurrence of avifauna in space and time, while LULC change has played a pivotal role in driving distributional dynamics of species with limited and declining habitat availability. Effective land management will be critical for improving species' resilience to climate change, especially during a season of relative resource scarcity and critical energetic trade-offs.

@article{doi101111gcb16063,
    author = "Saunders, Sarah P and Meehan, Timothy D and Michel, Nicole L and Bateman, Brooke L and DeLuca, William and Deppe, Jill L and Grand, Joanna and LeBaron, Geoffrey S and Taylor, Lotem and Westerkam, Henrik and Wu, Joanna X and Wilsey, Chad B",
    title = "Unraveling a century of global change impacts on winter bird distributions in the eastern United States.",
    year = "2022",
    journal = "Global change biology",
    abstract = "One of the most pressing questions in ecology and conservation centers on disentangling the relative impacts of concurrent global change drivers, climate and land-use/land-cover (LULC), on biodiversity. Yet studies that evaluate the effects of both drivers on species' winter distributions remain scarce, hampering our ability to develop full-annual-cycle conservation strategies. Additionally, understanding how groups of species differentially respond to climate versus LULC change is vital for efforts to enhance bird community resilience to future environmental change. We analyzed long-term changes in winter occurrence of 89 species across nine bird groups over a 90-year period within the eastern United States using Audubon Christmas Bird Count (CBC) data. We estimated variation in occurrence probability of each group as a function of spatial and temporal variation in winter climate (minimum temperature, cumulative precipitation) and LULC (proportion of group-specific and anthropogenic habitats within CBC circle). We reveal that spatial variation in bird occurrence probability was consistently explained by climate across all nine species groups. Conversely, LULC change explained more than twice the temporal variation (i.e., decadal changes) in bird occurrence probability than climate change on average across groups. This pattern was largely driven by habitat-constrained species (e.g., grassland birds, waterbirds), whereas decadal changes in occurrence probabilities of habitat-unconstrained species (e.g., forest passerines, mixed habitat birds) were equally explained by both climate and LULC changes over the last century. We conclude that climate has generally governed the winter occurrence of avifauna in space and time, while LULC change has played a pivotal role in driving distributional dynamics of species with limited and declining habitat availability. Effective land management will be critical for improving species' resilience to climate change, especially during a season of relative resource scarcity and critical energetic trade-offs.",
    url = "https://pubmed.ncbi.nlm.nih.gov/35060249/",
    doi = "10.1111/gcb.16063",
    pmid = "35060249"
}

Monitoring trends in wildlife communities is integral to making informed land management decisions and applying conservation strategies. Birds inhabit most niches in every environment and because of this they are widely accepted as an indicator species for environmental health. Traditionally, point counts are the common method to survey bird populations, however, passive acoustic monitoring approaches using autonomous recording units have been shown to be cost-effective alternatives to point count surveys. Advancements in automatic acoustic classification technologies, such as BirdNET, can aid in these efforts by quickly processing large volumes of acoustic recordings to identify bird species. While the utility of BirdNET has been demonstrated in several applications, there is little understanding of its effectiveness in surveying declining grassland birds. We conducted a study to evaluate the performance of BirdNET to survey grassland bird communities in Nebraska by comparing this automated approach to point count surveys. We deployed ten autonomous recording units from March through September 2022: five recorders in row-crop fields and five recorders in perennial grassland fields. During this study period, we visited each site three times to conduct point count surveys. We compared focal grassland bird species richness between point count surveys and the autonomous recording units at two different temporal scales and at six different confidence thresholds. Total species richness (focal and non-focal) for both methods was also compared at five different confidence thresholds using species accumulation curves. The results from this study demonstrate the usefulness of BirdNET at estimating long-term grassland bird species richness at default confidence scores, however, obtaining accurate abundance estimates for uncommon bird species may require validation with traditional methods.

@article{doi101371journalpone0306580,
    author = "Schuster, Grace E and Walston, Leroy J and Little, Andrew R",
    title = "Evaluation of an autonomous acoustic surveying technique for grassland bird communities in Nebraska.",
    year = "2024",
    journal = "PloS one",
    abstract = "Monitoring trends in wildlife communities is integral to making informed land management decisions and applying conservation strategies. Birds inhabit most niches in every environment and because of this they are widely accepted as an indicator species for environmental health. Traditionally, point counts are the common method to survey bird populations, however, passive acoustic monitoring approaches using autonomous recording units have been shown to be cost-effective alternatives to point count surveys. Advancements in automatic acoustic classification technologies, such as BirdNET, can aid in these efforts by quickly processing large volumes of acoustic recordings to identify bird species. While the utility of BirdNET has been demonstrated in several applications, there is little understanding of its effectiveness in surveying declining grassland birds. We conducted a study to evaluate the performance of BirdNET to survey grassland bird communities in Nebraska by comparing this automated approach to point count surveys. We deployed ten autonomous recording units from March through September 2022: five recorders in row-crop fields and five recorders in perennial grassland fields. During this study period, we visited each site three times to conduct point count surveys. We compared focal grassland bird species richness between point count surveys and the autonomous recording units at two different temporal scales and at six different confidence thresholds. Total species richness (focal and non-focal) for both methods was also compared at five different confidence thresholds using species accumulation curves. The results from this study demonstrate the usefulness of BirdNET at estimating long-term grassland bird species richness at default confidence scores, however, obtaining accurate abundance estimates for uncommon bird species may require validation with traditional methods.",
    url = "https://pmc.ncbi.nlm.nih.gov/articles/PMC11226020/",
    doi = "10.1371/journal.pone.0306580",
    pmcid = "PMC11226020",
    pmid = "38968184"
}