Dehesa nolina (Nolina interrata) and variegated dudleya (Dudleya variegata) are narrow endemic species that are priorities for management under the San Diego Management and Monitoring Program’s Management Strategic Plan for western San Diego County. Both species declined precipitously on the South Crest Preserve after fire and subsequent invasion by nonnative plants. To stabilize and increase populations, CBI conducted a 3-year program that included seed collection, nursery propagation, and outplanting of nursery-grown plants into restored habitat.
This conservation vision evaluates status and threats for the state-endangered plant species Dehesa nolina (Nolina interrata) on conserved lands in San Diego County, prioritizes management actions by population, and identifies survey and research needs. This document supplements information in the Management Strategic Plan (MSP) for Conserved Lands in western San Diego County (SDMMP 2016). The management strategy in Appendix A is consistent with the MSP with respect to threats and stressors, management focus group, and management goals and objectives.
This study presents an approach for identifying and describing geographic areas that support 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. The U.S. Geological Survey
(USGS) and San Diego Management and Monitoring Program (SDMMP) modeled suitable habitat for the target species under current and future climate scenarios; model results are in a separate report and referenced in this document, as appropriate. Target species include San Diego thornmint (Acanthomintha ilicifolia), thread-leaved brodiaea (Brodiaea filifolia), Otay tarplant (Deinandra conjugens), Dehesa nolina (Nolina interrata), and Parry’s tetracoccus (Tetracoccus dioicus).