April 2015 VEGETATION AND BIODIVERSITY MANAGEMENT PLAN Marin County Parks Marin County Open Space District VEGETATION AND BIODIVERSITY MANAGEMENT PLAN DRAFT Prepared for: Marin County Parks Marin County Open Space District 3501 Civic Center Drive, Suite 260 San Rafael, CA 94903 (415) 473-6387 [email protected] www.marincountyparks.org Prepared by: May & Associates, Inc. Edited by: Gail Slemmer Alternative formats are available upon request TABLE OF CONTENTS Contents GLOSSARY 1. PROJECT INITIATION ...........................................................................................................1-1 The Need for a Plan..................................................................................................................1-1 Overview of the Marin County Open Space District ..............................................................1-1 The Fundamental Challenge Facing Preserve Managers Today ..........................................1-3 Purposes of the Vegetation and Biodiversity Management Plan .....................................1-5 Existing Guidance ....................................................................................................................1-5 Mission and Operation of the Marin County Open Space District .........................................1-5 Governing and Guidance Documents ...................................................................................1-6 Goals for the Vegetation and Biodiversity Management Program ..................................1-8 Summary of the Planning Process and Document Overview ..........................................1-9 2. PRESERVE CONDITIONS: INVENTORY AND ASSESSMENT ..................................2-1 3. ASSESSMENT OF REGIONAL TRENDS, PRACTICES, AND SCIENCE ................3-1 Natural Resource Management (Protection and Restoration) .........................................3-2 Inventory and Monitoring .......................................................................................................3-3 Natural Resource Protection .................................................................................................3-5 Natural Resource Restoration ...............................................................................................3-7 Summary of Findings: Natural Resource Management ......................................................3-10 Invasive Plant Management .................................................................................................3-12 Prevention ...........................................................................................................................3-13 Early Detection ....................................................................................................................3-14 Mapping and Monitoring ......................................................................................................3-15 Treatments ..........................................................................................................................3-16 Environmental and Human Health and Safety Considerations ...........................................3-22 Examples of Invasive Plant Management Projects .............................................................3-24 Summary of Findings: Invasive Plant Management ............................................................3-24 Marin County Open Space District / Draft / Vegetation and Biodiversity Management Plan i TABLE OF CONTENTS Fuel Management ...................................................................................................................3-25 Fuel Modification Zones ......................................................................................................3-27 Other Fuel Reduction Strategies .........................................................................................3-37 Summary of Findings: Fuel Management ...........................................................................3-38 Forest Health Management...................................................................................................3-39 Overview of Forest Health Maintenance Programs ............................................................3-39 Management Practices Associated with Specific Threats ...................................................3-40 Summary of Findings: Forest Health Management .............................................................3-43 Management for Climate Change ........................................................................................3-44 Practices to Reduce Greenhouse Gases ............................................................................3-46 Practices to Support Natural Resilience to Climate Change ...............................................3-48 Practices to Support Natural Resilience to Sea Level Rise ................................................3-55 Summary of Findings: Management for Climate Change ...................................................3-58 4. FRAMEWORK FOR VEGETATION AND BIODIVERSITY MANAGEMENT PLAN ........................................................................................................4-1 A Comprehensive Approach to Vegetation Management .................................................4-1 Program Coordination and Prioritization .............................................................................4-1 Zone the Preserves to Identify Areas of Particular Importance or Concern ..........................4-1 Establish Vegetation Management Objectives Based on the Character of Each Zone ......4-17 Coordinate Vegetation Management Activities Needed to Accomplish the Objectives .......4-18 Inventory, Assessment, and Monitoring.............................................................................4-19 Baseline Inventories ............................................................................................................4-19 Rapid Assessments .............................................................................................................4-23 Project Monitoring ...............................................................................................................4-23 Natural Resource Management (Protection and Restoration) .......................................4-23 Protect High-Value Resources Before They Are Degraded ................................................4-23 Proactively Restore High-Value Habitat ..............................................................................4-29 Increase Habitat Connectivity to Create Travel Corridors ...................................................4-32 Invasive Plant Control and Integrated Pest Management ...............................................4-33 Prevent the Introduction and Spread of Invasive Species ..................................................4-35 Eradicate Pioneer Invasive Plant Infestations in All Zones and Low-Cover or Sparse-Cover Infestations in Legacy Zones ..............................................................4-35 Control or Contain Established Plant Infestations ...............................................................4-36 Fire Risk Management and Fire Hazard Reduction Strategies .......................................4-61 Place a High Priority on Fuel Reduction in Defensible Space Zones .................................4-61 ii Marin County Open Space District / Draft / Vegetation and Biodiversity Management Plan TABLE OF CONTENTS Use Ignition Prevention Zones to Manage Fire Risk Associated with Use by Agencies and the General Public ..............................................................................4-65 Identify and Prioritize Locations for Fuelbreaks ..................................................................4-66 Strategically Locate Ingress/Egress Zones .........................................................................4-71 Treat Fuel Modification Zones .............................................................................................4-71 Restore Nonessential Fuelbreaks and Fire Roads to Natural Conditions ...........................4-72 Maintain Staff Capability to Respond to Large Wildfires .....................................................4-72 Forest Health Management...................................................................................................4-73 Manage Hazards Associated with Weakened or Diseased Trees in High-Use Areas .........4-73 Selectively Treat Forest Pathogens ....................................................................................4-73 Manage to Achieve a Multiaged, Multistoried Forest Structure ...........................................4-76 Management of Vegetation Responses to Climate Change ............................................4-77 Consider the Effects of Vegetation Management on Greenhouse Gasses .........................4-78 Expand Monitoring and Adaptive Management to Support Response to Climate Change .4-78 Offset the Loss of Coastal Wetlands to Sea Level Rise by Supporting Replacement Wetlands in New Locations ......................................................................4-79 Cooperate with other Agencies and Researchers to Understand and Address the Effects of Climate Change .........................................................................4-80 5. PLAN IMPLEMENTATION ....................................................................................................5-1 Projects ......................................................................................................................................5-1