SAN BRUNO MOUNTAIN HABITAT CONSERVATION PLAN YEAR 2019-20 ACTIVITIES REPORT FOR FEDERALLY LISTED SPECIES Endangered Species 10(a)(1)(B) Permit TE215574-6 Prepared By: Evan Cole San Mateo County Parks Department 455 County Center, 4th Floor Redwood City, CA 94063 December 2020 TABLE OF CONTENTS Table of Contents I. INTRODUCTION ..............................................................................................................7 A. Covered Species Population Status ................................................................................... 7 2019 MISSION BLUE STATUS ......................................................................................................................... 8 2020 CALLIPPE SILVERSPOT STATUS.............................................................................................................. 8 2020 SAN BRUNO ELFIN STATUS ................................................................................................................... 9 RARE PLANT STATUS ..................................................................................................................................... 9 II. STATUS OF SPECIES OF CONCERN .........................................................................9 A. Mission Blue Butterfly (Icaricia icarioides missionensis) .............................................. 9 METHODOLOGY .......................................................................................................................................... 10 RESULTS ...................................................................................................................................................... 14 DISCUSSION ................................................................................................................................................ 20 CONCLUSIONS ............................................................................................................................................. 20 RECOMMENDATIONS .................................................................................................................................. 21 B. Callippe Silverspot Butterfly (Speyeria callippe callippe) ............................................ 23 METHODOLOGY .......................................................................................................................................... 23 RESULTS ...................................................................................................................................................... 27 DISCUSSION ................................................................................................................................................ 32 CONCLUSION............................................................................................................................................... 34 RECOMMENDATIONS .................................................................................................................................. 36 C. San Bruno Elfin (Callophrys mossii bayensis) .............................................................. 37 METHODOLOGY .......................................................................................................................................... 37 RESULTS ...................................................................................................................................................... 39 DISCUSSION ................................................................................................................................................ 41 CONCLUSIONS ............................................................................................................................................. 42 RECOMMENDATIONS .................................................................................................................................. 43 D. Bay Checkerspot Butterfly (Euphydryas editha bayensis) .......................................... 44 E. San Francisco Garter Snake (Thamnophis sirtalis tetrataenia) .................................. 45 F. California Red-legged Frog (Rana draytonii) .................................................................. 45 G. Plants of Concern ................................................................................................................ 45 III. VEGETATION AND HABITAT MANAGEMENT ........................................................45 A. Introduction ........................................................................................................................... 45 SITE HISTORY ............................................................................................................................................... 46 VEGETATION MANAGEMENT ....................................................................................................................... 46 B. Methods ................................................................................................................................. 47 LOCATION ................................................................................................................................................... 47 VEGETATION MANAGEMENT GROUPS ......................................................................................................... 48 VEGETATION MANAGEMENT TECHNIQUES .................................................................................................. 49 DATA ANALYSIS ........................................................................................................................................... 50 C. Results ................................................................................................................................... 50 PERSONNEL ................................................................................................................................................. 50 TREATMENT DISTRIBUTION ......................................................................................................................... 51 METHODS OF TREATMENT .......................................................................................................................... 52 December 2020 Page 1 SPECIES TREATED ........................................................................................................................................ 54 D. Discussion ............................................................................................................................. 54 HABITAT ENHANCEMENT ............................................................................................................................ 55 BUTTERFLY HOST PLANT ESTABLISHMENT ................................................................................................... 56 BAY CHECKERSPOT REINTRODUCTION ......................................................................................................... 56 NATURAL DISASTERS ................................................................................................................................... 57 E. Recommendations ............................................................................................................... 57 HABITAT ENHANCEMENT PRIORITIZATION ................................................................................................... 57 HOST AND NECTAR PLANT MONITORING ..................................................................................................... 58 IV. COVERED SPECIES AND VEGETATION MANAGEMENT PARTICIPANTS ...59 REFERENCES .......................................................................................................................60 Appendix A: 2015 Rare, Threatened, and Endangered Plant Survey Appendix B: Mission Blue, Callippe Silverspot, and San Bruno Elfin Butterfly Monitoring Raw Data Appendix C: Bay Checkerspot 2019-20 Reintroduction Semi-Annual Report December 2020 Page 2 GLOSSARY ANOVA - A statistical procedure called Analysis of Variance. ANOVA is used to test hypotheses about differences between two or more means without increasing the Type I error rate. ANOVA is employed to test whether the mean (or average) for butterfly abundance for a given year or on a given transect is statistically different than another year or transect. Correlation - Tests for a relationship between two variables. Endangered - Any species which is in danger of extinction throughout all or a significant portion of its range, other than a species of the class Insecta determined by the Secretary to constitute a pest whose protection under the provision of this Act would prevent an overwhelming and overriding risk to man (Federal Endangered Species Act, 1973). Endangered Species Act - The Federal Endangered Species Act (ESA) of 1973, as amended, 16 U.S.C. Sections 1531-1543. The State of California also has an endangered species act which is referred to as the California Endangered Species Act (CESA). Invasive Species - Non-native species of plants or animals that out-compete native species in a specific habitat. Fixed transects - Permanently marked transects that are surveyed year after year. Fixed transects provide a means to compare butterfly observations from year to year at specific locations using standard statistical procedures. Fixed points - Permanently marked points that are surveyed year after year. Habitat Conservation Plan (HCP) - The San Bruno Mountain Area Habitat Conservation Plan as adopted by the County Board