Using GIS to Analyze a Predator-Prey Relationship of the Common Raven and Desert Tortoise

Abstract

The common raven and desert tortoise are species both native to the Mojave Desert in southern California. For the last several decades, however, the raven population has increased significantly, while the desert tortoise population has declined to the point where it has been listed as a threatened species by the U.S. Fish and Wildlife Service under the Endangered Species Act. Prior studies have clearly demonstrated that predation by ravens is one cause of tortoise mortality; however, the correlation between raven population growth, predation locations, and surrounding features within the Mojave Desert (particularly anthropogenic) is less clear. This study focused on collecting and analyzing data on raven predation and habitat using ArcGIS in order to develop better management strategies for controlling raven population growth and increasing survival rates for desert tortoises. This project is a joint effort between the University of Redlands and the USFWS.