SONOMA COUNTY AGRICULTURAL PRESERVATION & OPEN SPACE DISTRICT CALABAZAS CREEK OPEN SPACE PRESERVE RESOURCE MANAGEMENT PLAN MAY 2016 747 Mendocino Avenue, Suite 100, Santa Rosa, CA 95401 TABLE OF CONTENTS 1.0 INTRODUCTION ............................................................................................................................1 1.1 Background & Plan Purpose ........................................................................................................................ 1 1.2 Location and Regional Context .............................................................................................................. 1 1.3 Data Collection ............................................................................................................................... ...............2 1.4 Next Steps ............................................................................................................................... .........................2 2.0 PRESERVE DESCRIPTION ............................................................................................................ 5 2.1 Legal Features ............................................................................................................................... ...................5 2.2 Geology, Soils and Erosion ...................................................................................................................... 5 2.3 Topography ............................................................................................................................... ......................8 2.4 Climate and Precipitation ........................................................................................................................ 8 2.5 Hydrology ............................................................................................................................... .........................9 2.6 Plant Communities ............................................................................................................................... ......13 2.7 Sensitive Habitats ....................................................................................................................................... 16 2.8 Special­Status Plants ............................................................................................................................... .22 2.9 Invasive Plants ............................................................................................................................... ...............25 2.10 Special­Status wildlife ............................................................................................................................ 31 2.11Mammals ............................................................................................................................... ........................37 2.12 Birds ............................................................................................................................... ..................................38 2.13Amphibians ............................................................................................................................... ...................39 2.14 Invasive Wildlife ........................................................................................................................................ 39 2.15 Habitat Continuity and Connectivity............................................................................................. 40 2.16 Fire Ecology and Its Influence on the Preserve .......................................................................... 41 2.17 Cultural Resources ............................................................................................................................... ....43 3.0 LAND USE AND MANAGEMENT............................................................................................. 44 3.1 Historic Land Use and Management ................................................................................................. 44 3.2 Current Zoning ............................................................................................................................... ..............45 3.3 Current Land Use and District Management Practices............................................................. 45 Table of Contents — i 4.0 RECOMMENDED MANAGEMENT STRATEGIES ................................................................. 50 4.1 Summary of Management Issues ........................................................................................................ 50 4.2 Physical Resources Management (PR) ..............................................................................................56 4.3 Plant Communities (PC) .......................................................................................................................... 60 4.4 Sensitive Habitat Management (SHM) ............................................................................................. 67 4.5 Special­Status Plants Management (SPM) ...................................................................................... 74 4.6 Invasive Plants Management (IPM) .................................................................................................... 76 4.7 Special­Status Animal Management (SAM) .................................................................................. 82 4.8 Critical Habitat Corridors (HC) ........................................................................................................... 85 4.9 Invasive Animals Management (IAM)............................................................................................... 85 4.10 Human Trespass and Illegal Activities Management (HT) ....................................................88 4.11 Cultural Resources (CR) ......................................................................................................................... 90 5.0 REGULATORY FRAMEWORK ................................................................................................... 91 6.0 MONITORING AND ADAPTIVE MANAGEMENT ............................................................... 93 REFERENCES .......................................................................................................................................96 APPENDIX A Historical Aerial Photography of the Preserve Area ...................................................................... 106 APPENDIX B ......................................................................................................................................108 Special­status Plants and Wildlife Documented in the Vicinity of the Preserve ............ 108 APPENDIX C ....................................................................................................................................... 112 Bird Species Occurring or Expected to Occur on the Preserve .................................................112 APPENDIX D .......................................................................................................................................114 Invasive Plant Species of Concern .......................................................................................................... 114 APPENDIX E.1 .................................................................................................................................... 121 List of All Vascular Plant Taxa Identified on the Calabazas Creek Open Space Preserve, Sonoma County, California. Compiled by Vollmar Natural Lands Consulting, 2013 ........121 APPENDIX E.2 ....................................................................................................................................133 Summary of Botanical Survey Methodologies ................................................................................. 133 APPENDIX F........................................................................................................................................136 Calabazas Creek Open Space Preserve Road Assessment ........................................................... 136 INTRODUCTION ..............................................................................................................................................136 Scope of Work ................................................................................................................................................... 137 1. Results ...............................................................................................................................................................139 2. Short Term Erosion Control and Erosion Prevention Plan ......................................................142 3. Long Term Erosion Control and Erosion Prevention Plan ........................................................ 143 4. Post project monitoring recommendations .................................................................................. 144 5. Conclusions ............................................................................................................................... ....................144 APPENDIX G...................................................................................................................................... 145 Calabazas Creek Open Space Preserve Sub­basin Characteristics ..........................................145 Table of Contents — ii APPENDIX H.....................................................................................................................................