Wolverine Range - CWHR M159 [ds1942]

The updated range map for North American wolverine (Gulo gulo) was developed using multiple sources of information (see Figure 1 of Wolverine Species Habitat Model Metadata: https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=245204). Using the historic range described in Grinnell et al. (1937) in The Furbearer Mammals of California as a foundation, we refined the boundary using historic and contemporary wolverine occurrence records and habitat suitability modeling to describe the updated range (See Appendix 1 of Wolverine Species Habitat Model Metadata: https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=245204). This range does not include likely long-distance migratory or dispersal areas and only represents the range that may be used as part of an established home range for this species.CWHR species range datasets represent the maximum current geographic extent of each species within California. Ranges were originally delineated at a scale of 1:5,000,000 by species-level experts more than 30 years ago and have gradually been revised at a scale of 1:1,000,000. Species occurrence data are used in defining species ranges, but range polygons may extend beyond the limits of extant occurrence data for a particular species. When drawing range boundaries, CDFW seeks to err on the side of commission rather than omission. This means that CDFW may include areas within a range based on expert knowledge or other available information, despite an absence of confirmed occurrences, which may be due to a lack of survey effort. The degree to which a range polygon is extended beyond occurrence data will vary among species, depending upon each species’ vagility, dispersal patterns, and other ecological and life history factors. The boundary line of a range polygon is drawn with consideration of these factors and is aligned with standardized boundaries including watersheds (NHD), ecoregions (USDA), or other ecologically meaningful delineations such as elevation contour lines. While CWHR ranges are meant to represent the current range, once an area has been designated as part of a species’ range in CWHR, it will remain part of the range even if there have been no documented occurrences within recent decades. An area is not removed from the range polygon unless experts indicate that it has not been occupied for a number of years after repeated surveys or is deemed no longer suitable and unlikely to be recolonized. It is important to note that range polygons typically contain areas in which a species is not expected to be found due to the patchy configuration of suitable habitat within a species’ range. In this regard, range polygons are coarse generalizations of where a species may be found. This data is available for download from the CDFW website: https://www.wildlife.ca.gov/Data/CWHR.