Baseline Biodiversity Survey for the Tenaja Corridor and Southern Santa Ana Mountains Final Report Prepared for: The Nature Conservancy U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY WESTERN ECOLOGICAL RESEARCH CENTER Baseline Biodiversity Survey for the Tenaja Corridor and Southern Santa Ana Mountains By Robert Fisher1,2 and Kevin Crooks1,3 U.S. GEOLOGICAL SURVEY WESTERN ECOLOGICAL RESEARCH CENTER Final Report Prepared for: The Nature Conservancy 1USGS-Biological Resources Division Department of Biology San Diego State University San Diego, CA 92182-4614 Current Addresses: 2San Diego Field Station USGS Western Ecological Research Center 5745 Kearny Villa Road, Suite M San Diego, CA 92123 3Department of Fishery and Wildlife Biology Colorado State University 115 Wagar Fort Collins, CO 80523 This report should be cited as: Fisher, R. and K. Crooks. 2001. Baseline Biodiversity Survey for the Tenaja Corridor and Southern Santa Ana Mountains. Final Report. USGS. Technical Report. Prepared for The Nature Conservancy. 72 pp. Sacramento, California 2001 i U.S. DEPARTMENT OF THE INTERIOR GALE A. NORTON, SECRETARY U.S. GEOLOGICAL SURVEY Charles G. Groat, Director The use of firm, trade, or brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey. For additional information, contact: Center Director Western Ecological Research Center U.S. Geological Survey 3020 State University Modoc Hall 3rd Floor, Room 3006 Sacramento, CA 95819 ii TABLE OF CONTENTS INTRODUCTION .............................................................................................................. 6 STUDY AREA ................................................................................................................... 6 RESEARCH GOALS ......................................................................................................... 7 BIODIVERSITY SURVEYS ............................................................................................. 7 Herpetofauna Species...................................................................................................... 7 Small Mammals .............................................................................................................. 9 Large Mammals .............................................................................................................. 9 Track Surveys ............................................................................................................... 10 Camera Surveys ............................................................................................................ 11 Birds.............................................................................................................................. 11 Point counts............................................................................................................... 11 Rapid Ornithological Inventories (ROI) ................................................................... 12 Bat Surveys ................................................................................................................... 13 Water Quality/Hydrology/Riparian Sampling .............................................................. 14 Road Transects.............................................................................................................. 16 CONCLUSIONS............................................................................................................... 17 Description of Tenaja Nodes ........................................................................................ 17 Tenaja Corridor Biodiversity Summary........................................................................ 20 Recommendations......................................................................................................... 22 Summary of Recommendations................................................................................ 24 ACKNOWLEDGEMENTS.............................................................................................. 24 REFERENCES ................................................................................................................. 25 APPENDIX....................................................................................................................... 66 iii LIST OF TABLES Table 1. Number of herpetofauna captured in the Tenaja Corridor through pitfall sampling, January 15, 1999 through September 20, 2000 (70 total sample days). .. 22 Table 2. Number of herpetofauna captured in the Santa Margarita Reserve by pitfall sampling, April 1, 1996 through September 1, 2000 (pitfall arrays 1-5: 230 sampling days; pitfall arrays 6-15: 50 sampling days)............................................................. 23 Table 3. Number of herpetofauna captured in Camp Pendleton through pitfall trapping, December 13, 1996 through September 2, 2000 (130 total sampling days)............. 24 Table 4. Number of small mammals captured in the Tenaja Corridor through pitfall sampling, January 15, 1999 through September 20, 2000 (70 total sample days). .. 25 Table 5. Number of small mammals captured in Santa Margarita Reserve through pitfall sampling, April 1, 1996 through September 1, 2000 (pitfall arrays 1-5: 230 sampling days; pitfall arrays 6-15: 50 sampling days)............................................................. 26 Table 6. Number of small mammals captured at Camp Pendleton by pitfall sampling, December 13, 1996 through September 2, 2000 (130 total sampling days)............. 27 Table 7. Mammalian carnivore species detected through baited track station surveys.... 28 Table 8. Mammalian carnivore species detected at camera stations in the Tenaja and Pechanga corridors.................................................................................................... 31 Table 9. Number of birds detected in the Tenaja corridor in Spring 1999 through point count surveys. ........................................................................................................... 33 Table 10. Number of birds detected in the Santa Ana Mountains project area through Spring 2000 point count surveys............................................................................... 34 Table 11. Birds banded through Rapid Ornithological Inventories (ROI) in the Santa Ana Mountains project area.............................................................................................. 35 Table 12. Bat species detected within the Santa Ana Mountains project area during spring and summer 1999, 2000............................................................................................ 36 Table 13. Water quality parameters for sampling stations within Santa Ana Mountains project area................................................................................................................ 37 Table 14. Species detected in Santa Ana project area during amphibian night driving surveys. ..................................................................................................................... 39 Table 15. Species detected in Santa Ana project area during road kill surveys. .............. 40 Table 16. Species detections within the four Tenaja habitat nodes. ................................. 41 iv LIST OF FIGURES Figure 1. Location of the southern Santa Ana Mountains study area............................... 44 Figure 2. Vegetative map of the southern Santa Ana Mountains study area.................... 45 Figure 3. Vegetative map of the Tenaja Corridor............................................................. 46 Figure 4. Location of herpetofauna pitfall sampling arrays in Santa Ana Mountains study area (see Figure 5 for Tenaja array numbers). .......................................................... 47 Figure 5. Location of herpetofauna pitfall sampling arrays in Tenaja Corridor............... 48 Figure 6. Location of mammalian carnivore baited track transects in Santa Ana Mountains study area. ............................................................................................... 49 Figure 7. Location of mammalian carnivore baited track transects in Tenaja Corridor... 50 Figure 8. Location of remotely-triggered camera stations in Santa Ana Mountains study area............................................................................................................................ 51 Figure 9. Location of remotely-triggered camera stations in Tenaja Corridor................. 52 Figure 10. Location of bird point count stations conducted April-June 2000 in Santa Ana Mountains study area. ............................................................................................... 53 Figure 11. Location of bird point counts stations conducted April-June 2000 in Tenaja Corridor..................................................................................................................... 54 Figure 12. Location of Rapid Ornithological Inventory (ROI) sampling stations in Santa Ana Mountains study area. ....................................................................................... 55 Figure 13. Location of Rapid Ornithological Inventory (ROI) sampling stations in Tenaja Corridor..................................................................................................................... 56 Figure 14. Location of bat sampling stations in Santa Ana Mountains study area........... 57 Figure 15. Location of bat sampling stations in Tenaja Corridor....................................