Herpetofauna Monitoring in the Mediterranean Coast Inventory and Monitoring Network: Cabrillo National Monument 2015–2018 Report
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National Park Service U.S. Department of the Interior Natural Resource Stewardship and Science Herpetofauna Monitoring in the Mediterranean Coast Inventory and Monitoring Network Cabrillo National Monument 2015–2018 Report Natural Resource Report NPS/MEDN/NRR—2019/1963 ON THE COVER California striped racer, Masticophis lateralis, in pitfall bucket during 2017 herpetofauna monitoring efforts. NPS Photo Herpetofauna Monitoring in the Mediterranean Coast Inventory and Monitoring Network Cabrillo National Monument 2015–2018 Report Natural Resource Report NPS/MEDN/NRR—2019/1963 Stephanie Root National Park Service Cabrillo National Monument 1800 Cabrillo Memorial Drive San Diego, California 92106 August 2019 U.S. Department of the Interior National Park Service Natural Resource Stewardship and Science Fort Collins, Colorado The National Park Service, Natural Resource Stewardship and Science office in Fort Collins, Colorado, publishes a range of reports that address natural resource topics. These reports are of interest and applicability to a broad audience in the National Park Service and others in natural resource management, including scientists, conservation and environmental constituencies, and the public. The Natural Resource Report Series is used to disseminate comprehensive information and analysis about natural resources and related topics concerning lands managed by the National Park Service. The series supports the advancement of science, informed decision-making, and the achievement of the National Park Service mission. The series also provides a forum for presenting more lengthy results that may not be accepted by publications with page limitations. All manuscripts in the series receive the appropriate level of peer review to ensure that the information is scientifically credible, technically accurate, appropriately written for the intended audience, and designed and published in a professional manner. Data in this report were collected and analyzed using methods based on established, peer-reviewed protocols and were analyzed and interpreted within the guidelines of the protocols. Views, statements, findings, conclusions, recommendations, and data in this report do not necessarily reflect views and policies of the National Park Service, U.S. Department of the Interior. Mention of trade names or commercial products does not constitute endorsement or recommendation for use by the U.S. Government. This report is available in digital format from the Mediterranean Coast Network of the Inventory and Monitoring Program and the Natural Resource Publications Management website. If you have difficulty accessing information in this publication, particularly if using assistive technology, please email [email protected]. Please cite this publication as: Root, S. 2019. Herpetofauna monitoring in the Mediterranean Coast Inventory and Monitoring Network: Cabrillo National Monument 2015–2018 report. Natural Resource Report NPS/MEDN/NRR—2019/1963. National Park Service, Fort Collins, Colorado. NPS 342/156562, August 2019 ii Contents Page Figures................................................................................................................................................... iv Tables .................................................................................................................................................... iv Appendices ............................................................................................................................................ iv Abstract .................................................................................................................................................. v Acknowledgments ................................................................................................................................ vii List of Terms ........................................................................................................................................ vii Introduction ............................................................................................................................................ 1 Methods .................................................................................................................................................. 3 Study Area ...................................................................................................................................... 3 Weather ..................................................................................................................................... 4 Field Methods ................................................................................................................................. 5 Results .................................................................................................................................................... 7 Lizards ............................................................................................................................................ 9 Snakes ........................................................................................................................................... 13 Other captures ............................................................................................................................... 14 Discussion ............................................................................................................................................ 15 Literature Cited .................................................................................................................................... 17 iii Figures Page Figure 1. Map of the location of the herpetofauna arrays within the Point Loma Ecological Area in San Diego, CA. ....................................................................................................... 4 Figure 2. Total number of herptile captures at each array during all 2015, 2016, 2017, and 2018 monitoring sessions. ............................................................................................................... 9 Figure 3. Sceloporus occidentalis captures by array from 2015 - 2018. ............................................. 10 Figure 4. Uta stansburiana captures by array from 2015 - 2018. ....................................................... 11 Figure 5. Aspidoscelis hyperythra captures by array from 2015 - 2018. ............................................ 12 Figure 6. Elgaria multicarinata captures by array from 2015 - 2018. ................................................ 13 Figure 7. Snakes captured during herptile monitoring from 2015 - 2018. .......................................... 14 Tables Page Table 1. Minimum measurement cut-off lengths for adult age class determination. ............................ 6 Table 2. Herptile and small mammal captures from 2015 - 2018 within the Point Loma Ecological Area. ..................................................................................................................................... 7 Appendices Page Appendix A. 2015 - 2018 Precipitation Data ....................................................................................... 18 Appendix B. Array Locations and Species Checklist. ......................................................................... 19 Appendix C. Coverboard and other incidental observations of note from 2015 - 2018. ..................... 22 Appendix D. Trap session dates and trap nights from 2015 - 2018. .................................................... 23 iv Abstract The use of pitfall traps and drift fencing is an effective method for monitoring many small animal species. This method has been used at Cabrillo National Monument in San Diego, California since 1995 to monitor trends in reptile and amphibian species (herptiles) within the park as part of the National Park Service - Mediterranean Coast Network Inventory and Monitoring Program. The park is located at the southern tip of the Point Loma peninsula near downtown San Diego and is surrounded by water and developed land essentially creating an island of native coastal sage scrub habitat. Twelve species of herptiles are currently found within the 163-acre park and nearby Navy land and species diversity has declined according to historical records. From 2015 - 2018, 11 of 12 herptile species were captured during sampling periods. Herptile species’ populations are an indicator of ecosystem health, therefore continuous monitoring is important to detect any significant changes in the herptile populations and to manage the park for future generations to enjoy. v Acknowledgments Many thanks go to the NPS Volunteers in Parks (VIPs) who dedicated their time and efforts in assisting with this project. Specifically, B. Sharp, W. Tam, G. Sharpe, D. Endicott, V. Buerger, B. Greenberg, P. Simpson, K. Lion, and others offered great assistance. Additional gratitude goes to the NPS staff and Science Education Team which includes A. Parker, A. Taylor, S. Wynns, A. Rosales, N. Ornelas, M. Pace, and A. Warneke. I am thankful for the expertise from D. Stokes of the San Diego Natural History Museum, C. Rochester and R. Fisher of the United States Geological Survey. I would like to thank the US Navy for their partnership with this study by allowing NPS to conduct work on military property. Much appreciation also goes to all NPS staff that inspires and educates the public of the flora and fauna of Cabrillo National Monument. L. Lee provided data management assistance throughout the