Publication Date


Committee Chair

Mark P. Kumler, Ph.D.

Committee Members

Phil Leitner, Ph.D.
Thomas Leuteritz, Ph.D.


The Mohave ground squirrel (Spermophilus mohavensis) is endemic to the northwestern region of the Mojave Desert. It is currently considered a threatened species by the state of California. Habitat loss due to human development within the species’ limited geographic area has been identified as a major contributor to the species’ threatened status. Habitat degradation due to livestock grazing, military training, and the increased abundance of invasive and non-invasive plant species are also serious conservation issues. It is important to be able to identify remaining areas of suitable habitat in order to conserve and manage viable Mohave ground squirrel populations. This project consisted of developing a habitat suitability model for the Mohave ground squirrel. The weighted overlay model approach was chosen after reviewing its effectiveness in similar case studies. This model allowed the combination of selected variables for integrated analysis that have been identified as important for the occurrence of the species. The Weighted Overlay tool from the Spatial Analyst toolbox – ArcGIS 9.1 was used to accomplish this task. The model was designed by assigning values of relative importance to the datasets as well as to layers themselves. The variables used were: elevation, slope, land cover, vegetation, geomorphology, mean winter precipitation (1976 – 2006), percentage of dry periods (1976 – 2006), and consecutive dry winter periods (1976 – 2006). The results obtained from the model will help to identify areas that are important for the conservation of the Mohave ground squirrel. It can be tested for accuracy against actual field data and modified to upgrade its predictive performance. This model will serve as a tool to help understand habitat variables that are critical for the survival of the species. It will also aid researchers in gathering more information on the species itself and its habitat requirements. (30464 kB)
Modeling Mohave Ground Squirrel Habitat (Poster)


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