The Species Distribution Modeling component of AKGAP began in September 2007 and was coordinated by the Alaska Natural Heritage Program at the University of Alaska Anchorage. Other project partners included the Environmental Science & Geography Programs & Spatial Ecosystem Analysis Lab (SEALAB) at the University of Alaska Southeast and the EWHALE lab-Biology and Wildlife Department at the University of Alaska Fairbanks.
Our objectives were to produce spatially explicit models, using consistent and repeatable methodologies, to predict the range and distribution of terrestrial vertebrate species in Alaska to support analysis of conservation status.
We mapped each species’ range (total areal extent occupied by a species) and distribution (spatial arrangement of environments suitable for occupation by a species). We used this approach to make regional maps more useful at various spatial scales and improve their utility for statewide, regional and local managers.
This map shows the range and distribution of the Alaska Marmot (Marmota broweri) in Alaska.
In an effort to improve the quality, precision, and application of the species distribution maps, we used two different modeling approaches for AKGAP.
- First a deductive modeling approach, which translates species habitat associations to quantifiable parameters on available spatial datasets, namely land cover data.
- And second, an inductive modeling approach, which relates known points of occurrence and their intersection with a suite of environmental variables (e.g.,elevation, climate).
- We intersected the results of the deductive and indicative models to produce a third “combined” model option.
The model selected as the best overall representation of the species distribution, using one of these three techniques, was defined as the final distribution model. The model displayed is the final species distribution model, which is a binary representation of presence/absence for each species within its range.
