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Species Viewer

Welcome to the Gap Analysis Program (GAP) Species Viewer

The Gap Analysis Program (GAP) Species Viewer displays data on vertebrate species ranges and distribution models for the continental U.S. as well as Alaska, Hawaii, Puerto Rico, and U.S. Virgin Islands. More specifically, species distribution models based on deductive modeling of habitat associations are displayed across entire species ranges for over 2000 species. Our goal is to build species range maps and distribution models with the best available data for assessing conservation status, conservation planning, and research (e.g., climate change impacts). Ranges are represented by 12-digit HUCs with attributes of occurrence/presence, origin, reproductive use, and seasonal use. Distribution models, created at 30 meter resolution, are based on habitat associations from published literature and core data sets, such as elevation and land cover. To date, we have a portion of our total species available through the GAP Species Viewer. As more species ranges and distribution models are completed, we will continually update our data on the GAP Species Viewer. Please check back for updates.

Why are species ranges and distribution models important?

Knowledge of a species geographic and ecological location is fundamental to conservation planning, conservation forecasting (e.g., climate change), and for understanding spatial patterns of species occurrence (e.g., species richness, historical vs. current). To contribute towards the knowledge regarding species geographic and ecological locations, USGS-GAP has embarked on an effort to create species distribution models across entire species ranges. These ranges and models represent a base on which we will build upon as new data become available. Furthermore, they will provide the basis of a national biodiversity assessment.

Species list

We created our species lists for the U.S. by initially compiling species lists from our regional projects in the Southwest (SWReGAP), Southeast (SEGAP), and Northwest (NWGAP). We then filled in areas not represented by these regional projects with species lists from all the remaining states (e.g., California, Midwestern and Northeastern states). Once a comprehensive list was compiled, each species’ taxonomic classification was verified using the most current information available.

Range maps

We defined a species range as a coarse representation of the total areal extent of a species or the geographic limits within which a species can be found. To represent these geographic limits, we used a national database of standardized 12-digit hydrological units (HUCs). Range maps were compiled and attributed with information from SWReGAP, SEGAP, NatureServe, and IUCN. Each range map contains information regarding occurrence/presence, origin, reproductive use, and seasonal use.

Distribution models

We defined a species distribution as the spatial arrangement of environments suitable for occupation by a species. In other words, a species distribution is created using a deductive model to predict areas suitable for occupation within a species range. Currently, we are focusing our efforts on building, expanding, or updating our deductive species models, but we will also expand our inductive modeling efforts over time. For species entirely within one of our regional projects, we are using existing distribution models created by those respective efforts as our national distribution model.

Additional data

Several key national ancillary data layers (e.g., elevation, stream velocity, distance to forest edge, etc.) have been created for our national modeling effort and are available for download.

How are species ranges and distribution models displayed?

A variety of filters can be applied to the species list to reduce the list or easily find a specific species. Or, auto fill searches can also be employed. Species range data, rather than species distribution models, are used to filter the species list. A single species range and/or distribution model can be displayed with seasonal attributes, such as summer and winter. Additionally, information regarding species range and/or model availability can be queried. A report on the model variables included in species models can be obtained from the viewer by clicking on the distribution model, as well as from the print map option.

Launch Species viewer