Natural Resource Management Plan for Mission Trails Regional Park San Diego, California City of San Diego Park & Recreation Department 202 C Street, MS5D San Diego, CA 92101 Natural Resource Management Plan for Mission Trails Regional Park, San Diego, California Prepared for Prepared by City of San Diego RECON Environmental, Inc. Parks & Recreation Department 1927 Fifth Avenue 202 C Street,MS5D San Diego, CA 92101-2358 San Diego, CA 92101 P 619.308.9333 F 619.308.9334 RECON Number 5286 January 17, 2017 Mission Trails Regional Park NRMP Table of Contents TABLE OF CONTENTS Acronyms vii 1.0 Introduction 1-1 2.0 Existing Conditions 1 2.1 Environmental Setting 1 2.1.1 Topography 2-1 2.1.2 Geology and Paleontology 2-1 2.1.3 Soils 2-5 2.1.4 Hydrology 2-6 2.2 Existing Biological Resources 2-10 2.2.1 Vegetation Communities 2-10 2.2.2 Plant Species 2-13 2.2.3 Wildlife Species 2-13 2.2.4 Wildlife Corridors 2-28 3.0 Regulatory Framework 3-1 3.1 Multiple Species Conservation Program 3-1 3.2 Multi-Habitat Planning Area Guidelines for MTRP 3-1 4.0 Biological Resource Management 4-1 4.1 Sensitive Biological Resources 4-1 4.1.1 Sensitive Species within MTRP 4-1 4.2 Threats to Biological Resources at MTRP 4-1 4.2.1 Preserve-level Threats 4-6 4.2.2 Region-wide Threats 4-9 4.3 Adaptive Management 4-12 4.3.1 Management Action Tool Kit 4-12 4.3.2 Management Prioritization 4-13 4.4 Priority Species Management at MTRP 4-15 4.4.1 San Diego Thornmint (Acanthomintha ilicifolia) 4-15 4.4.2 San Diego Ambrosia (Ambrosia pumila) 4-26 4.4.3 Variegated Dudleya (Dudleya variegata) 4-39 4.4.4 Willowy Monardella (Monardella viminea) 4-53 4.4.5 Coastal Cactus Wren (Campylorhynchus brunneicapillus couesi) 4-67 4.5 Priority Management Guilds at MTRP 4-77 4.5.1 Cliffs and Rocky Outcrops 4-77 4.5.2 East Elliott Clay Ridgelines 4-86 4.5.3 Tierrasanta Clay Ridge 4-95 4.5.4 Riparian Woodlands 4-102 4.5.5 Coastal Sage Scrub – Artemisia/Eriogonum 4-109 5.0 Budget and Schedule 5-1 6.0 References 6-1 i Mission Trails Regional Park NRMP Table of Contents FIGURES 2-1: Regional Location of Mission Trails Regional Park 2-2 2-2: Mission Trails Regional Park Areas 2-3 2-3: Topography within Mission Trails Regional Park 2-4 2-4: Soil Types Present within Mission Trails Regional Park 2-7 2-5: Soil Types Associated with Sensitive Species Occurrences Present within Mission Trails Regional Park 2-8 2-6: Hydrologic Units Present within Mission Trails Regional Park 2-9 2-7a: Vegetation Communities at MTRP (Holland Code) 2-14 2-7b: Vegetation Communities at MTRP (Holland Code) 2-15 2-7c: Vegetation Communities at MTRP (Holland Code) 2-16 2-7d: Vegetation Communities at MTRP (Holland Code) 2-17 2-7e: Vegetation Communities at MTRP (Holland Code) 2-18 2-8a: Vegetation Communities at MTRP (SANDAG) 2-23 2-8b: Vegetation Communities at MTRP (SANDAG) 2-24 2-8c: Vegetation Communities at MTRP (SANDAG) 2-25 2-8d: Vegetation Communities at MTRP (SANDAG) 2-26 2-8e: Vegetation Communities at MTRP (SANDAG) 2-27 2-9: Regional Wildlife Corridors at Mission Trails Regional Park 2-31 2-10: Preserve Level Connectivity within Mission Trails Regional Park 2-32 2-11: Wildlife Crossings at Mission Trails Regional Park 2-33 3-1: Project in Relation to MSCP Preserve Area 3-3 4-1: Approximate Location of Utility and Service Lines within Mission Trails Regional Park 4-11 4-2: San Diego Thornmint (Acanthomintha ilicifolia) Detected Occurrences: Mission Trails Regional Park 4-18 4-3: Comparison of Purple False Brome (BRDI) and Other Non-Native Species Cover at Area D Over Time 4-20 4-4: Conceptual Model for San Diego Thornmint (Acanthomintha ilicifolia) at MTRP 4-22 4-5: San Diego Thornmint (Acanthomintha ilicifolia) Management Actions: Mission Trails Regional Park 4-24 4-6: San Diego Ambrosia (Ambrosia pumila) Detected Occurrences: Mission Trails Regional Park 4-29 4-7: San Diego Ambrosia Population Area at MTRP Occurrence C 4-31 4-8: Conceptual Model for San Diego Ambrosia (Ambrosia pumila) at MTRP 4-33 4-9a: San Diego Ambrosia (Ambrosia pumila) Management Actions: Mission Trails Regional Park 4-34 4-9b: San Diego Ambrosia (Ambrosia pumila) Management Actions: Mission Trails Regional Park 4-35 4-9c: San Diego Ambrosia (Ambrosia pumila) Management Actions: Mission Trails Regional Park 4-36 ii Mission Trails Regional Park NRMP Table of Contents FIGURES (cont.) 4-10a: Variegated Dudleya (Dudleya variegata) Detected Occurrences: Mission Trails Regional Park 4-40 4-10b: Variegated Dudleya (Dudleya variegata) Detected Occurrences: Mission Trails Regional Park 4-41 4-10c: Variegated Dudleya (Dudleya variegata) Detected Occurrences: East Elliott 4-42 4-10: Three Selected Populations of Variegated Dudleya within the Fortuna Mountain Area 4-44 4-11: Three Selected Populations of Variegated Dudleya within the East Elliott Area 4-44 4-13a: Variegated Dudleya (Dudleya variegata) Management Actions: Mission Trails Regional Park 4-47 4-13b: Variegated Dudleya (Dudleya variegata) Management Actions: Mission Trails Regional Park 4-48 4-13c: Variegated Dudleya (Dudleya variegata) Management Actions: East Elliott 4-49 4-14: Conceptual Model for Variegated Dudleya (Dudleya variegata) at MTRP 4-51 4-15: Population Size (clumps vs. plants) of Willowy Monardella at Occurrence A within the West Sycamore Area 4-55 4-16: Clump to Individual Ratio of Willowy Monardella at Occurrence A at West Sycamore Area 4-56 4-17a: Willowy Monardella (Monardella viminea) Detected Occurrences: West Sycamore 4-57 4-17b: Willowy Monardella (Monardella viminea) Detected Occurrences: East Elliott 4-58 4-18: Conceptual Model for Willowy Monardella (Monardella viminea) at MTRP 4-61 4-19a: Willowy Monardella (Monardella viminea) Management Actions: West Sycamore 4-63 4-19b: Willowy Monardella (Monardella viminea) Management Actions: East Elliott 4-64 4-20: San Diego Cactus Wren (Campylorhynchus brunneicapillus couesi) Detected Occurrences: West Sycamore 4-70 4-21: San Diego Cactus Wren (Campylorhynchus brunneicapillus couesi) and Cacti: Regional Habitat Connectivity 4-71 4-22: Conceptual Model for Coastal Cactus Wren (Campylorhynchus brunneicapillus cousei) at MTRP 4-73 4-23: San Diego Cactus Wren (Campylorhynchus brunneicapillus couesi) Management Actions: West Sycamore 4-74 4-24: Cliffs and Rocky Outcroppings within Mission Trails Regional Park 4-81 4-25: Conceptual Model for Cliffs and Rocky Outcrops Management Guild 4-83 4-26: Cliff and Rocky Outcroppings Guilds Management Action: Mission Trails Regional Park 4-85 4-27: East Elliott Clay Ridgeline Guild within Mission Trails Regional Park 4-88 4-28: Conceptual Model for East Elliot Clay Ridgeline Management Guild 4-91 4-29: East Elliott Clay Ridgeline Guild Management Actions 4-92 4-30: Tierrasanta Clay Guild Presence within Mission Trails Regional Park 4-97 iii Mission Trails Regional Park NRMP Table of Contents FIGURES (cont.) 4-31: Conceptual Model for Tierrasanta Clay Ridge Management Guild 4-99 4-32: Tierrasanta Clay Guild Management Actions: Mission Trails Regional Park 4-101 4-33: Riparian Woodland Presence within Mission Trails Regional Park 4-103 4-34: Conceptual Model for Riparian Woodlands Management Guild 4-107 4-35a: Coastal Sage Scrub (Artemisia/Eriogonum) Guild within Mission Trails Regional Park 4-110 4-35b: Coastal Sage Scrub (Artemisia/Eriogonum) Guild within Mission Trails Regional Park 4-111 4-35c: Coastal Sage Scrub (Artemisia/Eriogonum) Guild within East Elliott 4-112 4-35d: Coastal Sage Scrub (Artemisia/Eriogonum) Guild within East Elliott 4-113 4-35e: Coastal Sage Scrub (Artemisia/Eriogonum) Guild within East Elliott 4-114 4-35f: Coastal Sage Scrub (Artemisia/Eriogonum) Guild within East Elliott 4-115 4-36a: California Gnatcatcher Habitat Evaluation Model Spring 2003 (pre-fire) 4-117 4-36b: California Gnatcatcher Habitat Evaluation Model Spring 2003 (pre-fire) 4-118 4-37a: California Gnatcatcher Habitat Evaluation Model 2010 (post fire) 4-119 4-37b: California Gnatcatcher Habitat Evaluation Model 2010 (post fire) 4-120 4-38a: Change in California Gnatcatcher Habitat Evaluation Model 2003-2010 4-121 4-38b: Change in California Gnatcatcher Habitat Evaluation Model 2003-2010 4-122 4-39: Coastal Sage Scrub (Artemisia/Eriogonum) Guild Management Actions 4-126 4-40: Conceptual Model for Coastal Sage Scrub (Artemisia/ Eriogonum) Management Guild 4-128 PHOTOGRAPHS 4-1: San Diego thornmint within a clay lens at MTRP 4-16 4-2: Degraded San Diego thornmint habitat on friable clay lens within the Fortuna Mountain sub-area within MTRP. Note invasion of purple false brome (light green grass between shrubs) 4-16 4-3: San Diego ambrosia at MTRP 4-27 4-4: San Diego ambrosia habitat within the Mission Gorge area, facing north 4-28 4-5: Willowy monardella within the West Sycamore area at MTRP 4-54 4-6: Willowy monardella habitat within the East Elliott area of MTRP 4-55 4-7: Coastal cactus wren habitat within the West Sycamore subarea of MTRP 4-69 4-8: Visitor Center Loop quarry cliff face, MTRP, facing northwest 4-78 4-9: West Kwaay Paay rocky outcropping, MTRP, facing northeast 4-79 4-10: Detail of soil crusts within East Elliott Clay Ridgeline Guild at MTRP 4-87 4-11: Vegetation present within the Tierrasanta Clay Ridge Management Guild boundary 4-96 4-12: Habitats present within the Riparian Woodland Guild at MTRP 4-104 4-13: Artemisia californica-dominated scrub at MTRP 4-116 4-14: Artichoke thistle infestation within the West Sycamore Subarea 4-127 iv Mission Trails Regional Park NRMP Table of Contents TABLES 2-1: Geologic Formations with High Paleontological Sensitivity within MTRP 2-5 2-2: Baseline Data Collection at MTRP 2-11 2-3: Holland Vegetation Communities and Land Cover Types within MTRP 2-12 2-4: SANDAG Vegetation Groups within MTRP 2-12 2-5: SANDAG Vegetation Community Alliance and Associations Observed at MTRP 2-19 2-6: Preserve Level Adjacency to Open Space at MTRP 2-29 2-7: Wildlife Undercrossings at SR-52 2-30 4-1: Sensitive Plant Species Observed within MTRP 4-2 4-2: Sensitive Wildlife Species Observed within MTRP 4-3 4-3: MSCP Covered Species, Required Area Specific Management Directives (ASMDs), and Associated Sections within The MTRP NRMP 4-4 4-4: Priority Sensitive Species at MTRP 4-14 4-5: Priority Management Guilds at MTRP 4-14 4-6: Size of Population D Over Time 4-17 4-7: Size of Populations A and B Over Time 4-19 4-8: Variegated Dudleya Location Parcel Ownership within MTRP 4-43 4-9: Variegated Dudleya Surveys on Selected Sites within MTRP (2001-2012) 4-43 4-10: Channel Entrenchment Classifications 4-65 4-11: CWMA Cacti Height Classes 4-76 4-12: Sensitive Species Observed within the Cliffs and Rocky Outcropping Management Guild at MTRP 4-80 4-13: Sensitive Species within the East Elliott Clay Ridgeline Management Guild 4-87 4-14: East Elliott Clay Ridgeline Survey: Sensitive Species Targets 4-93 4-15: Sensitive Species Observed within Tierrasanta Clay Ridge Management Guild at MTRP 4-96 4-16: Sensitive Species Observed within Riparian Woodlands at MTRP 4-105 4-17: Sensitive Species Observed within the Coastal Sage Scrub – Artemisia/Eriogonum Guild at MTRP 4-116 4-18: Acreage of High and Very High California Gnatcatcher at MTRP 4-123 4-19: Major Wildfires within Coastal Sage Scrub - Artemisia/Eriogonum Guild Boundaries at MTRP 4-124 5-1: Budget and Schedule 5-1 APPENDICES A-A: Plant Species Observed within MTRP A-B: Wildlife Species Observed/Detected within MTRP during 2009/10 Surveys A-C: Sensitive Species at MTRP not Selected for Individual Management A-D: Fire Management Plan v Acronyms Acronyms ASMD Area-specific Management Directives Cal-IPC California Invasive Plant Council Caltrans California Department of Transportation CDFW California Department of Fish and Wildlife City City of San Diego CNDDB California Natural Diversity Database CNPS California Native Plant Society’s CWA Clean Water Act CWMA Cactus Wren Management Area EO Elemental Occurrence GIS Geographic Information System GPS Global Positioning System JURMP Jurisdictional Urban Water Runoff Management Plan MBTA Migratory Bird Treaty Act MCAS Marine Corps Air Station MHPA Multi-Habitat Planning Area MDP Master Development Plan MPU Master Plan Update MSCP Multiple Species Conservation Program MSP Management Strategic Plan MSS Maritime Succulent Scrub MTRP Mission Trails Regional Park NAS National Academy of Sciences NRMP Natural Resource Management Plan RWQCB Regional Water Quality Control Board SANDAG San Diego Association of Governments SDCWA San Diego County Water Authority SDG&E San Diego Gas & Electric SDMMP San Diego Management and Monitoring Program SDNHM San Diego Natural History Museum SDSU San Diego State University SR-52 State Route 52 USACE U.S. Army Corps of Engineers USDA U.S. Department of Agriculture USFWS U.S. Fish and Wildlife Service USGS U.S. Geological Survey WMA Weed Management Area WNS White-Nose Syndrome WTI Western Tracking Institute vi Mission Trails Regional Park NRMP 1.0 Introduction 1.0 Introduction This Natural Resource Management Plan (NRMP) fulfills the City of San Diego’s (City) Multiple Species Conservation Program (MSCP) requirement to develop Area-Specific Management Directives (ASMDs) for the protection of natural resources at Mission Trails Regional Park (MTRP) (see MSCP Implementing Agreement Section 10.6.B, City Subarea Plan Section 1.5.6, and Final MSCP Plan Section 6.3). MTRP is a core biological area and regional wildlife corridor within the MSCP’s Multi-Habitat Planning Area (MHPA) and is managed to achieve the goals of the MSCP. The specific objectives of the NRMP are to: • Update sensitive species and habitat mapping. • Develop management guilds (management units based on habitat groupings with similar life-history requirements and/or threats) for groups of species and/or habitats. • Identify and prioritize threats to sensitive species and habitats. • Document current understanding of natural systems and species life history requirements using conceptual models. • Develop conservation and enhancement goals for individual populations/habitats and/or management guilds based on MSCP conditions of coverage (MSCP Plan Table 3-5). • Develop specific management actions (e.g., ASMDs) within an adaptive management framework to address the identified threats and ensure long-term, viable populations of these species within MTRP. • Develop protocols (e.g., data collection methods, success criteria) to evaluate adaptive management techniques and projects proposed in this plan. Page 1-1 Mission Trails Regional Park NRMP 2.0 Existing Conditions 2.0 Existing Conditions 2.1 Environmental Setting The MTRP planning envelope occupies a total of 9,780 acres and is located eight miles northeast of the City’s downtown (Figure 2-1). MTRP supports a wide range of native vegetation, habitats, and wildlife species within a diverse physical setting, and is a core biological resource area within the MHPA. MTRP has multiple notable features, including Cowles and Fortuna mountains, the San Diego River, Sycamore Landfill, Lake Murray, Mission Gorge, and the Old Mission Dam. For planning and discussion purposes, MTRP has been divided into six areas based on significant features of each. The designated areas are shown on Figure 2-2 and are:  Lake Murray  Cowles Mountain  Mission Gorge  Fortuna Mountain  East Elliott  West Sycamore MTRP is a regionally important recreation area for many outdoor sports, including: hiking, mountain biking, horseback riding, and rock climbing. The trails provide access for recreational and maintenance activities Trails are generally 2–4 feet in width, except where co-located with access roads. The existing trail system at MTRP is currently being reevaluated and revised in the Master Plan update associated with this NRMP. 2.1.1 Topography MTRP contains a variety of topographic features, including canyons, valleys, mountains, hills, and low-lying areas. The topography is generally very rugged, with elevations ranging dramatically throughout the different areas. Cowles Mountain is the highest point in MTRP at 1,591 feet (Figure 2-3). 2.1.2 Geology and Paleontology Geologically, the region of San Diego County in which MTRP is located consists of a layer cake sequence of Cenozoic sedimentary rock units which preserve portions of the last 47 million years of Earth history. These Cenozoic sedimentary rocks overlie a deeply eroded terrain formed in significantly older crystalline basement rocks (e.g., metasediments, metavolcanics, gabbros, granites, and tonalities) of the massive Peninsular Ranges Batholith. Page 2-1