California Wildlife Habitat Relationships

The California Wildlife Habitat Relationship (CWHR) System contains life history, geographic range, and management information for 712 species of amphibians, reptiles, birds, and mammals that occur within the state. It also contains detailed information on 59 habitat types and their spatial distribution. The core of the CWHR system is a database which relates these species to each of the habitats which support them, and an intuitive user interface enabling users to query this information. CWHR products aid in understanding, conserving, and managing California's wildlife.

*** Currently supported CWHR Version 9.0 is the final "download and install" version of this software. CWHR will be transitioning to an online web application scheduled for release early 2021 (April target). Stay tuned for more CWHR announcements ***

CWHR Products

The CWHR model is available through CWHR Version 9.0 software. See the CWHR User's Manual (PDF)(opens in new tab) for more information on using the program. The software can be used to produce the following types of reports:

  • A List of All Information about One or More Species. Information on taxonomy, legal status, life history, seasonality, locational occurrence, and CWHR model habitat suitability and element suitability ratings for selected species.
  • A List of Species for a Single Situation: a list of all wildlife species in the CWHR database predicted to occur in a user-specified habitat situation (habitat type, seral stages, location, habitat elements). More than one habitat type and stage can be specified. The query can be further limited by wildlife species legal status, seasonality, and suitability threshold levels. A typical application of the Single Situation Reports is to predict a list of species that potentially occur in a project area.
  • A List of Species Comparing Two Situations – species list: This report compares species lists between contrasting habitat situations. The report is a side-by-side comparison of predicted species lists for two different Single Situation queries. The Two Situation Comparison Report is useful to compare species lists between two different habitat scenarios for impact assessment, biodiversity considerations, or habitat management planning.
  • A List of Species Comparing Two Situations – habitat value. This report compares the habitat suitability ratings for each species in contrasting habitat situations. The report shows the average habitat suitability value for each species for each Single Situation query, and calculates the difference in habitat suitability value for each species. This type of Two Situation Comparison Report is useful when comparing habitat value between two different habitat scenarios for impact assessment, biodiversity considerations, or habitat management planning.
  • A List of Species Comparing Two Situations – weighted habitat value. This report is the same as the Habitat Value Comparison except that habitat types can be weighted by the user. The weights are typically based on acreage of the habitats. This type of Two Situation Comparison Report is useful when specific information to define weights, such as habitat area, is known between two contrasting habitat situations for impact assessment, biodiversity considerations, or habitat management planning.
  • A List of Species that Use a Given Element: a list of all species that use a selected habitat element (e.g. acorns, large snags, vernal pools) to meet their requirements for breeding, feeding or cover and the degree to which each species finds that element essential.
  • BIOVIEW: translates habitat suitability values for wildlife species into data that can be used in GIS, with an option to apply fuzzy logic to the calculation of these values.
  • Life history Notes for a Single Species: text notes, references and species range map.
  • Description of a Single Habitat: text notes for a selected habitat.
  • Species List: a complete species list of all amphibians, birds, mammals, and reptiles known to occur in California.

CWHR Software and GIS Data Downloads

Product Support

Conservation Applications

CWHR has been used for several large wildlife resource conservation efforts including the California Wildlife Action Plan, the Crucial Habitat Assessment Tool (CHAT)(opens in new tab) project, the Areas of Conservation Emphasis (ACE) project, and the Sierra Nevada foothills wildlife connectivity modeling project. It is one of the primary biological data sets used in an assessment of California's biodiversity for the "Atlas of the Biodiversity of California". CWHR is used in sustained yield planning efforts by several large private timber companies and is part of regulations adopted by the California Board of Forestry.

Field Forms and Guidelines

Research and Development

The information in CWHR is based on current published and unpublished biological information and professional judgment by recognized experts on California's wildlife. Research to improve the CWHR System is ongoing. Some examples are presented below.