CONSERVATION OF SAN JOAQUIN ANTELOPE SQUIRRELS (AMMOSPERMOPHILUS NELSONI): ECOLOGICAL ASSOCIATIONS, HABITAT SUITABILITY, AND CONSERVATION STRATEGIES PREPARED FOR: CALIFORNIA DEPARTMENT OF FISH AND WILDLIFE GRANT AGREEMENT NUMBER: P1640010 Prepared by: Brian L. Cypher1, Erica C. Kelly1, Reagen O’Leary2, Scott E. Phillips1, Larry R. Saslaw1, Erin N. Tennant2, and Tory L. Westall1 1California State University, Stanislaus Endangered Species Recovery Program One University Circle Turlock, CA 95382 2California Department of Fish and Wildlife Lands Unit 1234 East Shaw Avenue Fresno, CA 93710 July 2019 Tipton Kangaroo Rat Conservation CONSERVATION OF SAN JOAQUIN ANTELOPE SQUIRRELS (AMMOSPERMOPHILUS NELSONI): ECOLOGICAL ASSOCIATIONS, HABITAT SUITABILITY, AND CONSERVATION STRATEGIES Prepared by: Brian L. Cypher, Erica C. Kelly, Reagen O’Leary, Scott E. Phillips, Larry R. Saslaw, Erin N. Tennant, and Tory L. Westall California State University, Stanislaus – Endangered Species Recovery Program California Department of Fish and Wildlife – Lands Unit CONTENTS Acknowledgments ......................................................................................................................................... ii Executive Summary ..................................................................................................................................... iii Introduction ................................................................................................................................................... 1 Methods ......................................................................................................................................................... 2 Study Area ................................................................................................................................................................... 2 Surveys......................................................................................................................................................................... 2 Habitat Attributes ......................................................................................................................................................... 3 Habitat Suitability Modeling ........................................................................................................................................ 4 Results .......................................................................................................................................................... 12 Surveys....................................................................................................................................................................... 12 Habitat Attributes ....................................................................................................................................................... 14 Habitat Suitability Modeling ...................................................................................................................................... 16 Discussion .................................................................................................................................................... 18 Survey Technique ...................................................................................................................................................... 18 Habitat Attributes ....................................................................................................................................................... 20 Suitability Modeling .................................................................................................................................................. 22 Distribution ................................................................................................................................................................ 23 Conclusions ................................................................................................................................................................ 26 Recommendations ....................................................................................................................................... 28 1. Additional surveys on unsurveyed lands when possible........................................................................................ 28 2. Habitat protection .................................................................................................................................................. 28 3. Habitat management .............................................................................................................................................. 28 4. Further translocation research ............................................................................................................................... 28 5. Translocations to suitable, unoccupied habitat ....................................................................................................... 28 6. Habitat restoration .................................................................................................................................................. 29 Literature Cited .......................................................................................................................................... 30 Appendix A. Form used to assess habitat attributes on sites surveyed for San Joaquin antelope squirrels. ...................................................................................................................................................... 32 Appendix B. Raw output of San Joaquin antelope squirrel habitat suitability model prior to generalization. ............................................................................................................................................. 34 Appendix C. Location coordinates and dates for survey sites where San Joaquin antelope squirrels were detected. .............................................................................................................................................. 35 i Tipton Kangaroo Rat Conservation TABLES Table 1. Vegetation classification rankings used to model habitat suitability for San Joaquin antelope squirrels. ........... 6 Table 2. Habitat quality categories for San Joaquin antelope squirrels that combine vegetation rankings with categories of percent bare ground. ......................................................................................................................................... 11 Table 3. Habitat attributes on sites with and without San Joaquin antelope squirrel detections during surveys conducted in the San Joaquin Valley, CA. ............................................................................................................................. 15 Table 4. Results of habitat suitability modeling analysis for San Joaquin antelope squirrel including the amount of area in each category. ................................................................................................................................................... 16 Table 5. Results of field surveys for San Joaquin antelope squirrels by habitat quality category. .................................. 17 FIGURES Figure 1. Range map and California Natural Diversity Data Base occurrence records for the San Joaquin antelope squirrel in central California. .................................................................................................................................. 1 Figure 2. Extent of upland vegetation data by source within the range of the San Joaquin antelope squirrel in California. ............................................................................................................................................................... 7 Figure 3. Vegetation class ranking based on site surveys for the San Joaquin antelope squirrel in California. ................ 8 Figure 4. Estimated historical vegetation based on soil surveys within the range of the San Joaquin antelope squirrel in California (Phillips and Cypher 2015). ................................................................................................................... 9 Figure 5. Percent bare ground in three categories (>30%, 10-30%, <10%) within the range of the San Joaquin antelope squirrel in California. ............................................................................................................................................ 10 Figure 6. GIS model for combining vegetation and percent bare ground rankings to assess habitat suitability for the San Joaquin antelope squirrel in California. .......................................................................................................... 11 Figure 7. Results from camera stations (n = 319) established to survey for San Joaquin antelope squirrels in the San Joaquin Valley, California. ................................................................................................................................... 13 Figure 8. Results of habitat suitability modeling analysis for the San Joaquin antelope squirrel in California. ............. 18 ACKNOWLEDGMENTS This project was funded by the California Department of Fish and Wildlife (CDFW) with funds from the U.S. Fish and Wildlife Service, State Wildlife Grant Program. We thank John Battistoni and Krista Tomlinson at CDFW and Bernadette Paul at CSUS for administrative assistance and project support. We thank