SONOMA COUNTY AGRICULTURAL PRESERVATION & OPEN SPACE DISTRICT WRIGHT HILL RANCH OPEN SPACE PRESERVE MANAGEMENT PLAN Natural and Cultural Resources JANUARY 2017 TABLE OF CONTENTS 1 INTRODUCTION ................................................................................................................................1 1.1 Regional Planning Context ..........................................................................................................................1 1.2 Purpose and Goals ........................................................................................................................................2 1.3 Development Process .................................................................................................................................2 1.3.1 Document Development .................................................................................................................2 1.3.2 Technical Experts and Stakeholder Group Engagement .................................................3 2 PROPERTY DESCRIPTION .............................................................................................................4 2.1 Location and Regional Setting ................................................................................................................4 2.2 Adjacent Ownership and Land Uses ...................................................................................................4 2.3 Historic Land Uses of Wright Hill Ranch and Surrounding Areas .........................................4 2.3.1 Native American Communities...................................................................................................4 2.3.2 European Settlement ......................................................................................................................5 2.4 Current Land Uses .......................................................................................................................................6 2.5 Phase I Environmental Assessment ......................................................................................................7 3 PHYSICAL FEATURES .......................................................................................................................8 3.1 Topography and Elevation.........................................................................................................................8 3.2 Geology and Soils ........................................................................................................................................8 3.3 Climate and Precipitation .........................................................................................................................9 3.4 Watersheds ......................................................................................................................................................9 3.5 Viewsheds ........................................................................................................................................................9 4 BIOLOGICAL RESOURCES ........................................................................................................... 10 4.1 Introduction ...................................................................................................................................................10 4.2 Data Collection Methods ......................................................................................................................10 4.2.1 Botanical .............................................................................................................................................10 4.2.2 Wildlife ...............................................................................................................................................10 4.3 Vegetation Types and Alliances ...........................................................................................................12 4.3.1 Grasslands ............................................................................................................................................13 4.3.2 Coastal Scrub ....................................................................................................................................15 4.3.3 Wetlands ............................................................................................................................................16 4.3.4 Riparian Woodland and Scrub .................................................................................................17 4.3.5 Forests .................................................................................................................................................. 19 4.3.6 Ruderal Vegetation and Horticultural Plantings ..............................................................21 4.4 Wildlife Communities ..............................................................................................................................22 Table of Contents — i 4.4.1 Coastal Scrub ....................................................................................................................................23 4.4.2 Forests..................................................................................................................................................24 4.4.3 Ranch Complex ...............................................................................................................................25 4.5 Special-status Species and Vegetation Types .............................................................................26 4.5.1 Listed Plant Species .......................................................................................................................26 4.5.2 Special Native Vegetation ........................................................................................................ 26 4.5.3 Special-status Wildlife Species ...............................................................................................28 4.6 Management Considerations ...............................................................................................................35 5 EROSION ...........................................................................................................................................41 5.1 Introduction ...................................................................................................................................................41 5.2 Data Collection Methods ...................................................................................................................... 41 5.3 Assessment Results....................................................................................................................................42 5.3.1 2009 Road Assessment .................................................................................................................42 5.3.2 2013–2014 Road Assessments ...................................................................................................43 5.3.3 Gully Assessment Results ...........................................................................................................45 5.3.4 Road Repairs and Maintenance ............................................................................................. 46 5.4 Management Considerations .............................................................................................................. 46 6 FIRE ....................................................................................................................................................48 6.1 Introduction ..................................................................................................................................................48 6.2 Management Considerations ..............................................................................................................48 6.3 Fire Control Access and Public Safety Considerations ...........................................................50 7 LIVESTOCK GRAZING ....................................................................................................................51 7.1 Introduction ....................................................................................................................................................51 7.2 Grazing Considerations .............................................................................................................................51 7.3 Assessment Results ....................................................................................................................................53 7.3.1 Livestock Species ..............................................................................................................................53 7.3.2 Forage Quantity and Stocking Rate Estimates .................................................................53 7.3.3 Forage Quality and Production ................................................................................................55 7.3.4 Native Vegetation ...........................................................................................................................55 7.3.5 Riparian Areas, Water Quality, and Erosion ......................................................................56 7.3.6 Existing Infrastructure ...................................................................................................................57 7.4 Management