Puget Sound terrestrial vertebrates

The Encyclopedia of Puget Sound, in cooperation with the USGS, has developed a list of terrestrial vertebrates occurring within the Puget Sound basin.

Interesection of NW GAP Hydrological Units and Puget Sound WRIAs
Interesection of NW GAP Hydrological Units and Puget Sound WRIAs

This list of mammals, birds, amphibians and reptiles is available on the Encyclopedia's Species Library page, and was created by intersecting a Puget Sound boundary map with regional maps of species distributions from the Northwest Gap Analysis Program (NWGAP). The boundaries of the Puget Sound watershed were determined by USGS hydrologic units representing the Puget Sound drainage basin.

NWGAP is an effort by the United States Geological Survey (USGS) to create a database of information that can be used to monitor and evaluate species abundance, biodiversity, and the status of protected and endangered or at risk species. The USGS creates GAP maps by building multiple layers in a Geographic Information System (GIS), pulling data from various sources. The first layer contains land cover data taken from satellite images and field surveys, the second compiles data on species range and habitat preferences, and the third adds the boundaries of protected areas.

Because research shows that vegetation patterns determine biodiversity patterns, GAP focuses most closely on accurately representing vegetation type (comprised of vegetation, ecoregion, and vegetation zone). GAP maps include only vertebrate species in most states, partly due to lack of data for other species and partly because vertebrates are the focal point of many conservation efforts. Species ranges are defined using computer models that can predict where a species will occur based on the habitat preferences of that species. GAP creates separate range maps for each season, and codes the ranges by Hydrologic Unit (HU). Each HU comprises a watershed, with smaller units nesting within larger ones.

Adding protected areas to these maps allows USGS to monitor areas of high biodiversity that could benefit from conservation efforts, and monitor habitat loss and movement in and out of protected areas. The data is also designed to support better management plans and to predict how changes in land use might impact different species.