California Department of Fish and Wildlife


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Department of Fish & Wildlife
Biogeographic Data Branch

Physical Address:
1700 9th Street, 4th Floor
Sacramento, CA 95811

Mailing Address:
1416 9th Street, Suite 1266
Sacramento, CA 95814

(916) 322-2493 • Email BDB

Areas of Conservation Emphasis (ACE-II)

Areas of Conservation Emphasis (ACE-II) is a Department of Fish and Wildlife project that was begun in 2009 to provide data to help guide and inform conservation priorities in California.

The purpose of ACE-II was to:

  • Compile and analyze the best available statewide, spatial information on California's biological richness, including species diversity, rarity, and sensitive habitats,
  • Collect information on recreational needs and opportunities throughout the state, including fishing, hunting and wildlife-viewing,
  • Develop a set of tools and produce maps that summarize and display this information for use in conservation decision-making, and
  • Integrate these data into a spatial model that can be used to identify areas of biological or conservation interest throughout the state.

ACE-II provides an easily-accessible and standardized way to view the best available statewide data on California's biological richness and biodiversity. These datasets have many uses ranging from ecological research and modeling to local land-use planning and conservation decision making. The ACE-II data are dynamic and will be updated periodically as new data warrant.


  • CDFW Map Viewers are best viewed using Firefox, Chrome, Safari, or Internet Explorer 9+.
    The ACE-II Viewer is an on-line, interactive map interface for displaying and manipulating the ACE-II maps, data, and model results. The viewer includes additional spatial data such as stressors, protected status of lands, and connectivity and corridors that can be overlaid on the ACE-II data layers. The viewer tool allows the user to display and contrast the arrangement and relative value of California's unique biological resources, providing a first step toward setting conservation priorities statewide.
  • Weighted-additive model interface: A component of the ACE-II Interactive Viewer that allows the user to adjust the weights of the various layers and display a customized model result.
  • GIS Data: All spatial data layers can be displayed in the viewer or are available by request.
  • Ecoregional Model: Model results depicting relative biological richness within each USDA Ecoregion Section can be displayed in the viewer or are available upon request.

Reports and Further Information

Related Efforts

ACE-II is a component of a larger effort to plan for the conservation and management of California's resources at a landscape scale, which includes the California Wildlife: Conservation Challenges, California's Wildlife Action Plan; the California Climate Adaptation Strategy; and large-scale, multi-species conservation plans. The ACE-II products are complementary to the California Essential Habitat Connectivity Project, which identified large remaining blocks of intact habitat in California and modeled corridor linkages between these blocks. In addition, ACE-II is one building block in a long-term collaboration of 18 western states to develop robust Decision Support Systems for conservation planning.

For multi-state analysis, please visit the Western Governors' Crucial Habitat Assessment Tools (CHAT) website where a similar product is presented for California, in the context of the surrounding states. Please read our Comparison of CHAT and ACE-II document to better understand how these products differ.

Contact Information

Conservation Analysis Unit Coordinator
Biogeographic Data Branch
(916) 324-9265