Fine-scale mapping of species for the Northwest Gap Analysis Project

Fine scale mapping of species is important for species conservation and recovery at local and regional scales. Previously, the spatial and thematic resolutions at which Gap species mapping was conducted has not necessarily matched resolutions needed for local management, conservation, or recovery. However, Gap species mapping needs to be consistent across the Northwest (i.e., Montana, Wyoming, Idaho, Oregon, and Washington), which constrains spatial and thematic resolutions. We are attempting to address this mismatch of resolutions and maintain regional consistency by mapping species’ range, distribution, and habitat quality as distinct products. Range maps express species’ spatial arrangement at coarse resolutions, using 10-digit HUCs as map units. Species’ distributions are modeled as functions of regionally-mappable environmental variables, but also of select fine-scale variables not available region-wide. This allows managers to map distributions at finer spatial scales, if appropriate variables are available for project areas. Habitat quality maps highlight portions of region-wide distributions determined, via expert survey, to support high or low rates of reproduction and survival, and thus presenting more detailed thematic information. Our approach is being applied to approximately 650 Northwestern terrestrial vertebrates and relies on both deductive and inductive modeling approaches. Preliminary range, distribution, and habitat quality maps will be presented along with an evaluation of our approach for Northwestern species. We believe our approach will make Gap species mapping in the Northwest more applicable to conservation and recovery goals.