Service Description: The species range dataset represents the generalized geographic area within which the species is expected to regularly occur within California, without consideration of specific habitat requirements. Generally, range map boundaries are based on mapped species occurrence locations and expert knowledge and aligned with ecologically relevant units such as ecoregions or watersheds. The California Wildlife Habitat Relationship (CWHR) ranges have been developed over three decades and vary in age of last update. The date of last update can be found in the CWHR Revision Tracking Table at https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=115517.
GIS vector datasets representing species ranges are one component of the CWHR system. This system includes a web application that supplies information on California’s terrestrial vertebrates and the habitats upon which they depend, supports user queries, and houses spatial data on habitats and wildlife. The CWHR System was developed to support habitat conservation and management, land use planning, impact assessment, education, and research involving terrestrial vertebrates in California. CWHR contains information on life history, management status, geographic distribution, and habitat relationships for wildlife species known to occur regularly in California. CWHR species range datasets represent the maximum current geographic extent of regularly occurring terrestrial vertebrate species within California. These range datasets are used to generate a tabular database of species locations by county, ecoregion, and several other jurisdictional delineations to inform the CWHR system. This enables users to query for wildlife species meeting a set of location and habitat conditions. The species range datasets are also used by many groups to assist with development of biological surveys, and within CDFW to support species richness assessments for statewide conservation planning.
For more information about the CWHR system, visit the CWHR Homepage: https://www.wildlife.ca.gov/Data/CWHR.
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Has Versioned Data: false
Max Record Count: 2000
Supported query Formats: JSON
Supports applyEdits with GlobalIds: False
Supports Shared Templates: True
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Description: 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.
The following data sources were collated for the purposes of range mapping and species habitat modeling by RADMAP. Each focal taxon’s location data was extracted (when applicable) from the following list of sources. BIOS datasets are bracketed with their “ds” numbers and can be located on CDFW’s BIOS viewer: https://wildlife.ca.gov/Data/BIOS.
California Natural Diversity Database,
Terrestrial Species Monitoring [ds2826],
North American Bat Monitoring Data Portal,
VertNet,
Breeding Bird Survey,
Wildlife Insights,
eBird,
iNaturalist,
other available CDFW or partner data.
CDFW Staff, Conservation Analysis Unit, Biogeographic Data Branch.
The original CWHR range maps, used as a basis for updated ranges, were developed under the guidance of the California Interagency Wildlife Task Group (CIWTG), which was started in 1981 and consisted of several state and federal natural resource agencies and academic institutions including CDFW, Calfire, US Forest Service, and UC Davis.
Spatial Reference: 102100 (3857)
Initial Extent:
XMin: -13893932.5637
YMin: 3226640.23310455
XMax: -12910526.3619
YMax: 5778619.96339546
Spatial Reference: 102100 (3857)
Full Extent:
XMin: -13849232.2818
YMin: 3842856.1585
XMax: -12955226.6438
YMax: 5162404.038
Spatial Reference: 102100 (3857)
Units: esriMeters
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