This was a two year, TransNet-funded study (#5001586) on Crestridge Ecological Reserve and South Crest properties. Both properties support MSCP covered species and sensitive habitats, and function as critical landscape linkages between the northern and southern MSCP. Surrounded by residential development and heavily impacted by the 2003 Cedar Fire, these properties are subject to ongoing invasive plant issues. Specific task actions included invasive plant and covered plant species mapping and risk assessment s, invasive plant control and experimental studies, and development of an early detection invasive control plan.

The Management Strategic Plan for San Diego County requires prioritization and management for edaphic endemic plants, including the five rare plants addressed in this study. These species face low genetic diversity due to reduced population sizes, geographic isolation, and loss of pollinators. To enhance the resilience of these species across their ranges, we must manage threats to increase population sizes, identify potentially suitable habitat to connect existing populations, find or restore new populations, and provide opportunities for shifting distributions due to climate change. This study identifies and describes geographic areas that support the five edaphic endemic species and their habitat in a design that enhances resilience and provides opportunities for shifting distributions. We developed conceptual models to inform field studies and management, refined soils and vegetation attributes, and assessed regional population structure and threats. We used results to suggest prioritized locations for surveys, management, potential translocation, and additional conservation or acquisition. Project partners (U.S. Geological Survey and San Diego Management and Monitoring Program) modeled suitable habitat for the target species under current and future climate scenarios; we reference models as appropriate.

A project between the SDMMP and US Forest Service to establish and prioritize survey areas on Conserved Lands within the perimeter of the 2020 Valley Fire to document whether historic occurrences are extant and to discover new occurrences for 18 rare plant species. In 2022, AECOM and Conservation Biology Institute botanists surveyed areas for 18 target rare plant species and mapped the spatial extent of each new occurrence, counted or estimated the occurrence population size, and collected voucher specimens. They also photographed each new occurrence from a georeferenced location that captured a representative view of the occurrence. Botanists created a species list for the areas surveyed within the Valley Fire footprint. These areas included locations where rare plants were detected and mapped and negative data point areas where rare plants were not detected. In 2023, botanists shall again conduct surveys on suitable habitat on USFS lands burned in the 2020 Valley Fire. Results from these surveys should lead to a greater understanding of post-fire rare plant composition. In 2023, botanists may see species that did not emerge in the first year of surveys, and species found in the first year of surveys may have expanded their range. The 18 rare plant species included in the surveys are: San Diego thornmint (Acanthomintha ilicifolia), Marvin's allium (Allium marvinii), Western spleenwort (Asplenium vespertinum), Deane's milkvetch (Astragalus deanei), Encinitas baccharis (Baccharis vanessae), San Diego goldenstar (Bloomeria clevelandii), Orcutt's brodiaea (Brodiaea orcuttii), Lakeside ceanothus (Ceanothus cyaneus), San Miguel savory (Clinopodium chandleri), Variegated dudleya (Dudleya variegata), Mission Canyon bluecup (Githopsis diffusa filicaulis), Ramona horkelia (Horkelia truncata), Heart-leaved pitcher sage (Lepechinia cardiophylla), Felt-leaved pitcher sage (Monardella hypoleuca lanata), Chaparral nolina (Nolina cismontana), Gander's ragwort (Packera ganderi), Moreno currant (Ribes canthariforme), and Parry's tetracoccus (Tetracoccus dioicus).