Modeling of Wildlife Dispersal Habitat at Stevens Pass, Washington

The connectivity of habitats for wildlife is of increasing conservation concern. Advances in the scientific understanding of species movement and dispersal, along with geographic information system (GIS) analytical tools, now permit habitat connectivity to be rigorously evaluated. The greater Stevens Pass region along Highway 2 in Washington State provides an important north-south connection for many wildlife species. Thus, initial scoping for proposed projects related to the Stevens Pass Ski Area identified habitat connectivity as an important issue to evaluate. The objective of this modeling exercise was to develop “existing conditions” dispersal models for the following four focal wildlife species: grizzly bears (Ursus arctos), Canada lynx (Lynx Canadensis), wolverines (Gulo gulo), and American martens (Martes americana). These models can be used to evaluate the potential effects of proposed land-use changes on wildlife dispersal habitat in the Stevens Pass region. The authors chose to specifically model dispersal habitat—as opposed to “core” or “source” habitat—because of the specific interest in ultimately using the model to evaluate the effects of land-use change on wildlife habitat permeability or connectivity. Models focused on wildlife movement (e.g., dispersal, range shifts), therefore, are most appropriate. For each species, the authors also built a baseline model that excluded direct anthropogenic effects (i.e., roads, trails, houses/buildings). These were deemed “baseline” models. Dispersal habitat models were created using a GIS approach that will be useful in evaluating the effects of various land-use changes on wildlife dispersal habitat throughout the project area. A scientific review team consisting of resource managers, consultants, and members of the NGO community was assembled to: (1) review and select appropriate modeling methods; (2) identify appropriate GIS data for analysis; (3) assign species-specific permeability values to GIS layer attributes; and (4) review model outputs. The outcome includes maps and GIS grid files that depict the ease with which focal species would be predicted to disperse through any particular grid cell within the modeled extent—expressed as “dispersal habitat suitability.” Dispersal habitat suitability at any given grid cell is calculated as the product of the permeability values for all layers at that cell, and is interpreted as the cumulative effect of all variable inputs at that cell. The models assessed only dispersal habitat and not core or source habitat for each species. Alternative and complementary modeling approaches (e.g., cost-weighted distance, least-cost corridor, circuit theory) building on the results of this effort may be applied by other researchers or interested parties to further evaluate habitat connectivity, or to assess the effects of various management decisions on dispersal habitat.


  • English

Media Info

  • Media Type: Web
  • Features: Appendices; Figures; References; Tables;
  • Pagination: 36p

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Filing Info

  • Accession Number: 01153622
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Mar 31 2010 2:06PM