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Species Vision

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). These data are intended to describe patterns of species geographic location and basic ecological characteristics (e.g., habitat associations). Spatial patterns of species occurrence across landscapes can provide insights into biodiversity conservation (e.g., species richness).

Strategy show details

In 2008, GAP embarked on an effort to begin creating species distribution models across entire species ranges for a large number of species that occur in the continental US. We started with creating a species list for the US based on the species lists that were developed for the Southwest (SWReGAP), Southeast (SEGAP), and Northwest (NWGAP) GAP projects. We then compiled species lists from all the remaining states (e.g., California, Midwestern and Northeastern states). Once a comprehensive list was compiled, each species was verified using the most current information regarding that species (Crother 2008, Wilson and Reeder 2005, American Ornithological Union’s 2008 checklist).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 (Morrison and Hall 2002). To represent these geographic limits, we used a national database of standardized 12-digit hydrological units (HUCs). We are using information from NatureServe, SWReGAP, and SEGAP to create our species ranges. The NWGAP species ranges will be incorporated as soon as they are finalized.We are using each species range to provide the biological context within which to build our species 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 model to predict areas suitable for occupation within a species range. Our distribution maps, which are the result of our distribution models, are created at a 30m resolution. We are using deductive modeling approaches based on habitat associations and expert input. We will also be starting to collect species point observations to begin including inductive modeling as well. However, whatever modeling approach is used for creating a species distribution model, it will be applied consistently across its range. For those species that have ranges entirely within the regional extents of SWReGAP, SEGAP, or NWGAP projects, we are using the existing distribution models as our national distribution models for that 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). This is our first attempt to build species models across species ranges rather than stopping at state boundaries. These models will provide a base from which we can iteratively improve the model when new data become available and they will provide the basis of a national biodiversity assessment. GAP’s modeling strategy is aimed towards our new national level vision. We believe our strategy over the next 1-2 years will position us well for conducting nationwide biodiversity assessments while also building and expanding our species modeling data, models, and expertise.

Current Status show details

Currently there are several species modeling efforts that are contributing towards our national goal. There are regional modeling efforts, some of which were started prior to moving to national scale models (e.g., NWGAP) while others are working within the national framework (e.g., NEGAP). And there are modeling efforts based on species groups, such as reptiles or birds, which all have a national perspective.To date, we have 880 species ranges and 260 distribution models completed. These completed species ranges and distribution models are all available via our web site for viewing and downloading. As more species ranges and distribution models are completed, which will be several hundred over the next year; we will continually update our web site. Please check our Species Viewer regularly for new species ranges and distribution models. Contact us if you have questions about the status of a particular species.At present, our main modeling approach is deductive (i.e., habitat associations); however, NWGAP and Alaska GAP species modeling efforts include inductive modeling (i.e., statistical modeling using point occurrences). We are focusing our initial efforts on building, expanding, or updating our deductive speciesmodels, but we are also expanding our inductive modeling efforts over time.

As a result of our current deductive modeling, we also have created core data needed for conducting national species modeling. This includes a national wildlife habitat relationship database on which all our current deductive modeling efforts are based. This database contains wildlife habitat relationships to land cover and other spatial habitat parameters (e.g., elevation, slope) based on literature, taxonomic information (e.g., ITIS codes), and information about the status of the modeling effort for each species (e.g., available model, model spatial extent, partners involved, and projected completion).

Much of this information is integrated into our Species Viewer. Furthermore, several key national ancillary data layers (e.g., stream velocity, distance to forest edge) have been created through our deductive modeling and are available for download.

We intend to continue with our deductive modeling while simultaneously gearing up our inductive modeling effort, which will require a species point occurrence database and national spatial environmental layers, such as temperature and precipitation.

We view modeling as an iterative process in which we will update our ranges and models as new data and information become available.