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 Special-Status Plants ................................................................................................................................22 2.9 Invasive Plants ..............................................................................................................................................25 2.10 Special-Status wildlife ............................................................................................................................31 2.11 Mammals .......................................................................................................................................................37 2.12 Birds .................................................................................................................................................................38 2.13 Amphibians ..................................................................................................................................................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 Special-Status Plants Management (SPM) ......................................................................................74 4.6 Invasive Plants Management (IPM) ....................................................................................................76 4.7 Special-Status 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 Special-status 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 Sub-basin Characteristics ..........................................145 Table of Contents — ii APPENDIX H ......................................................................................................................................146