Crucial Habitat Assessment Tool
Mapping Application
Until the Alaska CHAT is ready for publication, ADF&G has prepared a suite of habitat maps, some of which are currently displayed on the WAFWA CHAT. Additional sample maps are posted here to provide a framework of what to expect when we do publish the tool.
Map Display
The CHAT is displayed in a hexagon format. The information displayed in the CHAT is shown in the hexagon format at a resolution of 1 square mile per hexagon. In the 'zoomed out' view, seven hexagons are conglomerated to form one cog. This is why the view changes as you zoom into the map.
These map products originate from the Alaska Habitat Management Guide which has been digitized and incorporated into the CHAT Hexagon framework.
The following map products are specialized to fit the WAFWA model for CHAT, as aligned with common labels and features used for habitat conservation.
Crucial Habitat Rank
This is an aggregated layer reflecting five habitat values: 1) terrestrial species of concern, comprised of threatened and endangered species, G1/G2, T1/T2, and others; 2) other species identified in Alaska's Comprehensive Wildlife Conservation Strategy; 3) aquatic species of concern based on the ADF&G Anadromous Waters Catalog; 4) species richness; and 5) an index of freshwater integrity based on the 2010 National Fish Habitat Partnership's (NFHP) assessment of human effects on fish habitat. This rolled-up habitat map will be updated as ADF&G adds more layers and data to its assessment of crucial habitat across the landscape.
Crucial Habitat Data Input Layers
Terrestrial Species of Concern
This layer includes mammals and birds that are federally listed as threatened, endangered, candidate, or proposed; Natural Heritage G1/G2 or T1/T2; and high-profile species of current management concern.
Aquatic Species of Concern
The Aquatic Species of Concern layer includes waters important for Alaska's anadromous fish species. All records within the Anadromous Waters Catalog were joined with polylines representing sections of water bodies. These polylines were then intersected with the 10 mi2 hexagon map for Alaska. If any part of a hexagon contained a polyline it was attributed as containing a water body important for anadromous fishes.
Freshwater Integrity
The National Fish Habitat Action Plan (NFHAP) HUC 12 coverage for Habitat Condition Index (HCI) was intersected with the 10 m2 hexagon map covering Alaska. The greatest NFHAP HCI score for each hexagon was used for setting the priority level. A head/tail breaks classification (Jiang, 2012) was used to determine 6 priority levels due to the heavy-tailed distribution of the NFHAP scores.
Species of Concern
Species of state and/or national conservation importance, including those vulnerable to extinction or those undergoing regional decline or other species requiring special management attention. Most states defined their Species of Concern list using State Wildlife Action Plan "Species of Greatest Conservation Need" and NatureServe conservation status rankings, and other criteria in some cases.
Layers in Processing
Riparian and Wetland Habitat Distribution
Areas that represent unique and/or sensitive environments and function to support animal and plant diversity with respect to wildlife objectives and connectivity.
Species of Economic and/or Recreational Importance
These may include game or sportfish species especially if habitat needs are not already covered by mapping "Species of Concern."