¬ RANCHO SANTA ANA BOTANIC GARDEN OCCASIONAL PUBLICATIONS NUMBER 17 A CONSERVATION ASSESSMENT FOR CASTILLEJA GRISEA (SAN CLEMENTE ISLAND PAINTBRUSH, OROBANCHACEAE) SULA VANDERPLANK, KIMBERLY O’CONNOR, BRYAN MUNSON AND DAWN LAWSON Published by Rancho Santa Ana Botanic Garden, 1500 North College Avenue, Claremont, California 91711 2019 RANCHO SANTA ANA BOTANIC GARDEN OCCASIONAL PUBLICATIONS NUMBER 17 A CONSERVATION ASSESSMENT FOR CASTILLEJA GRISEA (SAN CLEMENTE ISLAND PAINTBRUSH, OROBANCHACEAE) SULA VANDERPLANK, KIMBERLY O’CONNOR, BRYAN MUNSON AND DAWN LAWSON RANCHO SANTA ANA BOTANIC GARDEN OCCASIONAL PUBLICATIONS RANCHO SANTA ANA BOTANIC GARDEN OCCASIONAL PUBLICATIONS (ISSN 1094-1398) are published at irregular intervals in volumes of various sizes. This series of publications is designed to feature results of original botanical research by members of the Rancho Santa Ana Botanic Garden staff, or by botanists who have collaborated in a Garden program. Proceedings of symposia sponsored by the Garden may also be published in this series. The RANCHO SANTA ANA BOTANIC GARDEN OCCASIONAL PUBLICATIONS series is published by Rancho Santa Ana Botanic Garden, 1500 North College Avenue, Claremont, California 91711-3157. For information about orders for RANCHO SANTA ANA BOTANIC GARDEN OCCASIONAL PUBLICATIONS, contact Irene Holiman at the address above or via e-mail: [email protected] or fax at (909) 626-7670. For all other inquiries, contact Vanessa Ashworth at [email protected]. General information about the Garden and its programs can be obtained at www.rsabg.org. (Cover photograph by Sula Vanderplank) PUBLICATION DATA A Conservation Assessment for Castilleja grisea (San Clemente Island Paintbrush, Orobanchaceae). September 2019. Sula Vanderplank, Kimberly O’Connor, Bryan Munson and Dawn Lawson. RANCHO SANTA ANA BOTANIC GARDEN OCCASIONAL PUBLICATIONS, Number 17, vi + 34 pages. ISSN 1094-1398. Series Editor Vanessa Ashworth; Managing Editor Lucinda McDade. First printing: 100 copies, September 2019. Copyright © 2019 by Rancho Santa Ana Botanic Garden. This publication was printed with support from the United States Department of the Navy. Dr. Sula Vanderplank: Research Associate and Postdoctoral Scholar, San Diego State University Research Foundation, San Diego, California 92182 ([email protected]) Ms. Kimberly O’Connor: Natural and Cultural Resources Program Manager, Commander, U.S. Pacific Fleet, U.S. Department of the Navy, San Diego, California 92135 Mr. Bryan Munson: Botany Program Manager, Naval Base Coronado, U.S. Department of the Navy, San Diego, California 92135 Dr. Dawn Lawson: Ecologist, Space and Naval Warfare Systems Center Pacific, U.S. Department of the Navy, San Diego, California 92152 v TABLE OF CONTENTS LIST OF FIGURES ....................................................................................................................................................... vi LIST OF TABLES ........................................................................................................................................................ vi LIST OF APPENDICES ............................................................................................................................................... vi LIST OF MAPS ............................................................................................................................................................ vi 1.0 EXECUTIVE SUMMARY ...................................................................................................................................... 1 2.0 SCOPE AND PURPOSE ......................................................................................................................................... 1 3.0 METHODS ............................................................................................................................................................... 1 4.0 BACKGROUND ...................................................................................................................................................... 1 4.1 Species Description .................................................................................................................................................. 1 4.2 Taxonomic History ................................................................................................................................................... 2 4.3 Regulatory History ................................................................................................................................................... 3 5.0 BIOLOGY, ECOLOGY AND HUMAN USES ...................................................................................................... 3 5.1 Biology and Ecology ................................................................................................................................................ 3 5.2 Habitat ...................................................................................................................................................................... 4 5.3 Human Uses ............................................................................................................................................................. 5 6.0 DISTRIBUTION, ABUNDANCE AND POPULATION TRENDS ...................................................................... 5 6.1 Distribution and Abundance .................................................................................................................................... 5 6.2 Population Trends .................................................................................................................................................... 9 6.3 Threats and Limiting Factors ................................................................................................................................. 11 6.4 Threats with Regard to Listing Requirements—FIVE-FACTOR ANALYSIS ..................................................... 11 FACTOR A: Present or Threatened Destruction, Modification, or Curtailment of Habitat or Range ..... 11 1. Land Use ......................................................................................................................................................... 11 2. Non-Native [Invasive] Plant Species ............................................................................................................. 12 3. Fire and Fire Management ............................................................................................................................ 13 4. Soil Erosion .................................................................................................................................................... 15 FACTOR B: Overutilization for Commercial, Recreational, Scientific or Educational Purposes ............. 16 FACTOR C: Disease or Predation .................................................................................................................... 17 FACTOR D: Inadequacy of Existing Regulatory Mechanisms ...................................................................... 17 FACTOR E: Other Natural or Human-Caused Factors Affecting Its Continued Existence ...................... 18 1. Movement of Vehicles and Troops ................................................................................................................. 18 2. Fire ................................................................................................................................................................. 18 3. Climate Change .............................................................................................................................................. 18 7.0 RECENT CONSERVATION ACTIONS .............................................................................................................. 18 7.1 Conservation Status ................................................................................................................................................ 19 7.2 Conservation Recommendations ............................................................................................................................ 19 8.0 CONCLUSIONS .................................................................................................................................................... 19 ACKNOWLEDGMENTS ............................................................................................................................................ 19 REFERENCES CITED ................................................................................................................................................ 20 APPENDICES .............................................................................................................................................................. 23 MAPS ........................................................................................................................................................................... 26 vi LIST OF FIGURES Fig. 1–2. Castilleja grisea.—1. Close-up of flower.—2. Habit. .................................................................................... 4 Fig. 3. Increasing population trend in Castilleja grisea after removal of non-native herbivores. ............................... 10 LIST OF TABLES Table 1. Presence of Castilleja species on the California Channel Islands (excluding San Clemente Island) .............. 2 Table 2. Associated species of Castilleja grisea taken