GAP has delineated species range and predicted distribution maps for more than 2,000 species that occur within the continental US as well as Alaska, Hawaii, and Puerto Rico. Our goal is to build species range maps and distribution models with the best available data for assessing conservation status, conservation planning, and research.
Species Data Download
Data available is comprised from the CONUS_2001 data set. Specifically, the data is based on land cover conditions during 2001 for the conterminous United States.
Species Data Web Services
Species habitat maps are available in an Open Geospatial Consortium (OGC) Web Map Service (WMS).
Why are these Data Important?
Knowledge of a species geographic and ecological location is fundamental to many aspects of biodiversity conservation and for understanding spatial patterns of species occurrences. Furthermore, they will provide the basis of a national biodiversity assessment (gap analysis of species protection status).
How National GAP Species Data are being used
- To enhance understanding of spatial patterns of species occurrence (e.g., species richness).
- As a core data input to a national biodiversity assessment of vertebrate species occurring in United States.
- To provide information about the location of a species to enhance understanding of how that species will adapt to the effects of climate change.
- As core datasets from which new iterations of the maps and models can be developed as additional data become available.
Description of the CONUS Data Set
Species List
We started with a species list for each of the four terrestrial vertebrate classes of interest (i.e. mammals, amphibians, reptiles, birds). The list was compiled from three standard checklists including:
Banks, R. C., R. T. Chesser, C. Cicero, J. L. Dunn, A. W. Kratter, I. J. Lovette, P. C. Rasmussen, J. V. Remsen, Jr., J. D. Rising, D. F. Stotz, and K. Winker. 2008. Forty-ninth supplement to the American Ornithologists Union Check-list of North American Birds. The Auk 125:758-768. DOI: 10.1525/auk.2008.9708
Crother, B. I. 2008. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. 6th edition. Herpetological Circular No. 37, Society for the Study of Amphibians and Reptiles.
Wilson, D. E., and D. M. Reeder. 2005. Mammal Species of the World. A Taxonomic and Geographic Reference, 3rd edition. Johns Hopkins University Press.
Known Range Maps
GAP species range data are coarse representations of the total areal extent a species occupies - in other words, the geographic limits within which a species can be found (Morrison and Hall 2002). These data provide the geographic extent within which we delineate areas of suitable habitat for terrestrial vertebrate species in their species’ habitat maps. The range maps are created by attributing a vector file derived from the 12-digit Hydrologic Unit Dataset (USDA NRCS 2009). Modifications to that dataset are described here. Attribution of the season range for each species was based on the literature and online sources (See Cross Reference section of the metadata). Attribution for each hydrologic unit within the range included values for occurrence (extant, possibly present, potentially present, extirpated), season (year-round, summer, winter, migratory, vagrant), origin (native, introduced, reintroduced, vagrant), and reproductive use (breeding, non-breeding, both). These species range data provide the biological context within which to build our species distribution models.
Predicted Habitat Maps
Gap Analysis Project (GAP) habitat maps are predictions of the spatial distribution of suitable environmental and land cover conditions within the United States for individual species. Mapped areas represent places where the environment is suitable for the species to occur (i.e. suitable to support one or more life history requirements for breeding, resting, or foraging), while areas not included in the map are those predicted to be unsuitable for the species. While the actual distributions of many species are likely to be habitat limited, suitable habitat will not always be occupied because of population dynamics and species interactions. Furthermore, these maps correspond to midscale characterizations of landscapes, but individual animals may deem areas to be unsuitable because of presence or absence of fine-scale features and characteristics that are not represented in our models (e.g. snags, vernal pools, shrubby undergrowth). These maps are intended to be used at a 1:100,000 or smaller map scale.
These habitat maps are created by applying a deductive habitat model to remotely-sensed data layers within a species’ range. The deductive habitat models are built by compiling information on species’ habitat associations into a relational database. Information is compiled from the best available characterizations of species’ habitat, which included species accounts in books and databases, as well as primary peer-reviewed literature. The literature references for each species are included in the “Species Habitat Model Report” and “Machine Readable Habitat Database Parameters” files attached to each habitat map item in the ScienceBase repository. For all species, the compiled habitat information is used by a biologist to determine which of the ecological systems and land use classes represented in the National Gap Analysis Project’s (GAP) Land Cover Map Ver. 1.0 that species is associated with. The name of the biologist who conducted the literature review and assembled the modeling parameters is shown as the “editor” type contact for each habitat map item in the repository.
For many species, information on other mapped factors that define the environment that is suitable is also entered into the database. These factors included elevation (i.e. minimum, maximum), proximity to water features, proximity to wetlands, level of human development, forest ecotone width, and forest edge; and each of these factors corresponded to a data layer that is available during the map production. The individual datasets used in the modeling process with these parameters are also made available in the ScienceBase repository. The “Machine Readable Habitat Database Parameters” JSON file attached to each species' habitat map item has an “input_layers” object that contains the specific parameter names and references (via Digital Object Identifier) to the input data used with that parameter. The specific parameters for each species were output from the database used in the modeling and mapping process to the “Species Habitat Model Report” and “Machine Readable Habitat Database Parameters” files attached to each habitat map item in the repository.
How To Cite These Data:
Known Range Maps
U.S. Geological Survey – Gap Analysis Project, 2018, U.S.Geological Survey – Gap Analysis Project Species Range Maps CONUS_2001: U.S. Geological Survey data release, https://doi.org/10.5066/F7Q81B3R
Predicted Habitat Maps
U.S. Geological Survey – Gap Analysis Project, 2018, U.S. Geological Survey – Gap Analysis Project Species Habitat Maps CONUS_2001: U.S. Geological Survey data release, https://doi.org/10.5066/F7V122T2
Data Limitations
It should be noted that all our ranges and distribution models are predictions about the occurrence of a species within the U.S. GAP ranges and distribution models are intended for use at the landscape scale (i.e., areas the size of square kilometers). They are not intended to be precise predictions of species occurrence/absence at local scales (areas the size of square meters). It is important for GAP data users to evaluate the suitability of the data for their intended purpose.
GAP aims to use the best available information to create species ranges and distribution models. GAP relies on existing data and expert opinions from partners and collaborators (e.g., State Natural Heritage Programs).
Species range maps and distribution models are viewed as a single iteration based on the best available information. We encourage biologists and data users to assess GAP’s species ranges and distribution models, and to give us feedback so that we can continually improve our models and ultimately our ability to conserve biodiversity.
All of GAP’s ranges and distribution models have been reviewed by experts and compared to other data sources for accuracy. The accuracy of the species ranges and distribution models varies from species to species in part because habitat preferences and behaviors vary seasonally and annually (Edwards et al. 1996). However, those species for which thorough knowledge of habitat preferences exists are better represented than those for which little is known (i.e., rare or small populations) or vary widely both spatially and temporally. Species with highly restrictive distributions are very difficult to model accurately because their habitat cannot be predicted within the 30 m resolution of our land cover data and distribution maps. We accept the uncertainty within some ranges and distribution models because we believe these data provide basic information and serve an important purpose by highlighting where more data are needed.
Despite these limitations, we believe GAP species ranges and distribution models are valuable and relevant for addressing broad landscape level conservation questions and research.
References
Banks, R. C., R. T. Chesser, C. Cicero, J. L. Dunn, A. W. Kratter, I. J. Lovette, P. C. Rasmussen, J. V. Remsen, Jr., J. D. Rising, D. F. Stotz, and K. Winker. 2008. Forty-ninth supplement to the American Ornithologists’ Union Check-list of North American Birds. The Auk 125:758-768. Available from: https://pubs.er.usgs.gov/publication/5224902.
Crother, B. I. 2008. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. 6th edition. Herpetological Circular No. 37, Society for the Study of Amphibians and Reptiles. Available from: www.ssarherps.org/pages/comm_names/Index.php
Morrison, M. L., and L. S. Hall. 2002. Standard terminology: Toward a common language to advance ecological understanding and application. Pages 43-52 in Predicting Species Occurrences: Issues of accuracy and scale. Editors: J. M. Scott, P. J. Heglund, and M. L. Morrison, et al., Island Press.
U.S. Geological Survey and U.S. Department of Agriculture, Natural Resources Conservation Service, 2009, Federal guidelines, requirements, and procedures for the national Watershed Boundary Dataset: U.S. Geological Survey Techniques and Methods 11:3, 55 p. Available from: https://pubs.usgs.gov/tm/11/a3/pdf/tm11-a3_1ed.pdf
Wilson, D. E., and D. M. Reeder. 2005. Mammal Species of the World. A Taxonomic and Geographic Reference, 3rd edition. Johns Hopkins University Press. Available from: https://academic.oup.com/jmammal/article/88/3/824/1073866.
Non-CONUS Species Data Sets:
- Alaska – Alaska GAP Website >>
- Puerto Rico – Puerto Rico Species data >> (Contact GAP for details: amckerrow@usgs.gov or jpmagee@usgs.gov)
Below are data downloads, metadata, and web services associated with the Gap Analysis Project species data. Prior to downloading any ancillary data, please read the Data Notes to ensure they will meet your data needs.
U.S. Geological Survey - Gap Analysis Project Species Habitat Maps CONUS_2001
U.S. Geological Survey - Gap Analysis Project Species Range Maps CONUS_2001
GAP has delineated species range and predicted distribution maps for more than 2,000 species that occur within the continental US as well as Alaska, Hawaii, and Puerto Rico. Our goal is to build species range maps and distribution models with the best available data for assessing conservation status, conservation planning, and research.
Species Data Download
Data available is comprised from the CONUS_2001 data set. Specifically, the data is based on land cover conditions during 2001 for the conterminous United States.
Species Data Web Services
Species habitat maps are available in an Open Geospatial Consortium (OGC) Web Map Service (WMS).
Why are these Data Important?
Knowledge of a species geographic and ecological location is fundamental to many aspects of biodiversity conservation and for understanding spatial patterns of species occurrences. Furthermore, they will provide the basis of a national biodiversity assessment (gap analysis of species protection status).
How National GAP Species Data are being used
- To enhance understanding of spatial patterns of species occurrence (e.g., species richness).
- As a core data input to a national biodiversity assessment of vertebrate species occurring in United States.
- To provide information about the location of a species to enhance understanding of how that species will adapt to the effects of climate change.
- As core datasets from which new iterations of the maps and models can be developed as additional data become available.
Description of the CONUS Data Set
Species List
We started with a species list for each of the four terrestrial vertebrate classes of interest (i.e. mammals, amphibians, reptiles, birds). The list was compiled from three standard checklists including:
Banks, R. C., R. T. Chesser, C. Cicero, J. L. Dunn, A. W. Kratter, I. J. Lovette, P. C. Rasmussen, J. V. Remsen, Jr., J. D. Rising, D. F. Stotz, and K. Winker. 2008. Forty-ninth supplement to the American Ornithologists Union Check-list of North American Birds. The Auk 125:758-768. DOI: 10.1525/auk.2008.9708
Crother, B. I. 2008. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. 6th edition. Herpetological Circular No. 37, Society for the Study of Amphibians and Reptiles.
Wilson, D. E., and D. M. Reeder. 2005. Mammal Species of the World. A Taxonomic and Geographic Reference, 3rd edition. Johns Hopkins University Press.
Known Range Maps
GAP species range data are coarse representations of the total areal extent a species occupies - in other words, the geographic limits within which a species can be found (Morrison and Hall 2002). These data provide the geographic extent within which we delineate areas of suitable habitat for terrestrial vertebrate species in their species’ habitat maps. The range maps are created by attributing a vector file derived from the 12-digit Hydrologic Unit Dataset (USDA NRCS 2009). Modifications to that dataset are described here. Attribution of the season range for each species was based on the literature and online sources (See Cross Reference section of the metadata). Attribution for each hydrologic unit within the range included values for occurrence (extant, possibly present, potentially present, extirpated), season (year-round, summer, winter, migratory, vagrant), origin (native, introduced, reintroduced, vagrant), and reproductive use (breeding, non-breeding, both). These species range data provide the biological context within which to build our species distribution models.
Predicted Habitat Maps
Gap Analysis Project (GAP) habitat maps are predictions of the spatial distribution of suitable environmental and land cover conditions within the United States for individual species. Mapped areas represent places where the environment is suitable for the species to occur (i.e. suitable to support one or more life history requirements for breeding, resting, or foraging), while areas not included in the map are those predicted to be unsuitable for the species. While the actual distributions of many species are likely to be habitat limited, suitable habitat will not always be occupied because of population dynamics and species interactions. Furthermore, these maps correspond to midscale characterizations of landscapes, but individual animals may deem areas to be unsuitable because of presence or absence of fine-scale features and characteristics that are not represented in our models (e.g. snags, vernal pools, shrubby undergrowth). These maps are intended to be used at a 1:100,000 or smaller map scale.
These habitat maps are created by applying a deductive habitat model to remotely-sensed data layers within a species’ range. The deductive habitat models are built by compiling information on species’ habitat associations into a relational database. Information is compiled from the best available characterizations of species’ habitat, which included species accounts in books and databases, as well as primary peer-reviewed literature. The literature references for each species are included in the “Species Habitat Model Report” and “Machine Readable Habitat Database Parameters” files attached to each habitat map item in the ScienceBase repository. For all species, the compiled habitat information is used by a biologist to determine which of the ecological systems and land use classes represented in the National Gap Analysis Project’s (GAP) Land Cover Map Ver. 1.0 that species is associated with. The name of the biologist who conducted the literature review and assembled the modeling parameters is shown as the “editor” type contact for each habitat map item in the repository.
For many species, information on other mapped factors that define the environment that is suitable is also entered into the database. These factors included elevation (i.e. minimum, maximum), proximity to water features, proximity to wetlands, level of human development, forest ecotone width, and forest edge; and each of these factors corresponded to a data layer that is available during the map production. The individual datasets used in the modeling process with these parameters are also made available in the ScienceBase repository. The “Machine Readable Habitat Database Parameters” JSON file attached to each species' habitat map item has an “input_layers” object that contains the specific parameter names and references (via Digital Object Identifier) to the input data used with that parameter. The specific parameters for each species were output from the database used in the modeling and mapping process to the “Species Habitat Model Report” and “Machine Readable Habitat Database Parameters” files attached to each habitat map item in the repository.
How To Cite These Data:
Known Range Maps
U.S. Geological Survey – Gap Analysis Project, 2018, U.S.Geological Survey – Gap Analysis Project Species Range Maps CONUS_2001: U.S. Geological Survey data release, https://doi.org/10.5066/F7Q81B3R
Predicted Habitat Maps
U.S. Geological Survey – Gap Analysis Project, 2018, U.S. Geological Survey – Gap Analysis Project Species Habitat Maps CONUS_2001: U.S. Geological Survey data release, https://doi.org/10.5066/F7V122T2
Data Limitations
It should be noted that all our ranges and distribution models are predictions about the occurrence of a species within the U.S. GAP ranges and distribution models are intended for use at the landscape scale (i.e., areas the size of square kilometers). They are not intended to be precise predictions of species occurrence/absence at local scales (areas the size of square meters). It is important for GAP data users to evaluate the suitability of the data for their intended purpose.
GAP aims to use the best available information to create species ranges and distribution models. GAP relies on existing data and expert opinions from partners and collaborators (e.g., State Natural Heritage Programs).
Species range maps and distribution models are viewed as a single iteration based on the best available information. We encourage biologists and data users to assess GAP’s species ranges and distribution models, and to give us feedback so that we can continually improve our models and ultimately our ability to conserve biodiversity.
All of GAP’s ranges and distribution models have been reviewed by experts and compared to other data sources for accuracy. The accuracy of the species ranges and distribution models varies from species to species in part because habitat preferences and behaviors vary seasonally and annually (Edwards et al. 1996). However, those species for which thorough knowledge of habitat preferences exists are better represented than those for which little is known (i.e., rare or small populations) or vary widely both spatially and temporally. Species with highly restrictive distributions are very difficult to model accurately because their habitat cannot be predicted within the 30 m resolution of our land cover data and distribution maps. We accept the uncertainty within some ranges and distribution models because we believe these data provide basic information and serve an important purpose by highlighting where more data are needed.
Despite these limitations, we believe GAP species ranges and distribution models are valuable and relevant for addressing broad landscape level conservation questions and research.
References
Banks, R. C., R. T. Chesser, C. Cicero, J. L. Dunn, A. W. Kratter, I. J. Lovette, P. C. Rasmussen, J. V. Remsen, Jr., J. D. Rising, D. F. Stotz, and K. Winker. 2008. Forty-ninth supplement to the American Ornithologists’ Union Check-list of North American Birds. The Auk 125:758-768. Available from: https://pubs.er.usgs.gov/publication/5224902.
Crother, B. I. 2008. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. 6th edition. Herpetological Circular No. 37, Society for the Study of Amphibians and Reptiles. Available from: www.ssarherps.org/pages/comm_names/Index.php
Morrison, M. L., and L. S. Hall. 2002. Standard terminology: Toward a common language to advance ecological understanding and application. Pages 43-52 in Predicting Species Occurrences: Issues of accuracy and scale. Editors: J. M. Scott, P. J. Heglund, and M. L. Morrison, et al., Island Press.
U.S. Geological Survey and U.S. Department of Agriculture, Natural Resources Conservation Service, 2009, Federal guidelines, requirements, and procedures for the national Watershed Boundary Dataset: U.S. Geological Survey Techniques and Methods 11:3, 55 p. Available from: https://pubs.usgs.gov/tm/11/a3/pdf/tm11-a3_1ed.pdf
Wilson, D. E., and D. M. Reeder. 2005. Mammal Species of the World. A Taxonomic and Geographic Reference, 3rd edition. Johns Hopkins University Press. Available from: https://academic.oup.com/jmammal/article/88/3/824/1073866.
Non-CONUS Species Data Sets:
- Alaska – Alaska GAP Website >>
- Puerto Rico – Puerto Rico Species data >> (Contact GAP for details: amckerrow@usgs.gov or jpmagee@usgs.gov)
Below are data downloads, metadata, and web services associated with the Gap Analysis Project species data. Prior to downloading any ancillary data, please read the Data Notes to ensure they will meet your data needs.