Developing management strategies and priorities for rare species on conserved lands
Nolina interrata (Dehesa nolina, Dehesa beargrass) is a state-endangered species known only from southern San Diego County, California and northern Baja California, Mexico. This fire-adapted plant is restricted to gabbro or metavolcanic soils in chaparral, scrub, and grassland habitats. Many of the populations in San Diego County occur on conserved lands, but face a number of threats, including invasive species, altered fire regimes, and potentially, climate change. In response to management concerns, the Conservation Biology Institute developed a science-based Conservation Vision and Management Strategy for Dehesa nolina in San Diego County. This project was funded through a grant from the San Diego Association of Governments (SANDAG) Transnet Environmental Mitigation Fund. At the regional level, this vision assessed the distribution, status, and threats of populations on conserved lands through data and literature review, site visits, and interviews with land managers. Products include spatial data layers, an updated matrix of threats and stressors, management recommendations, and prioritization of conserved populations for management. At the preserve-level, we increased and stabilized the existing Dehesa nolina population on the South Crest Preserve through species augmentation (seed collection, contract growing of plants, out-planting) and erosion control. These actions also benefitted another MSCP covered species onsite, Dudleya variegata (variegated dudleya), as well as sensitive native grassland habitat. Management actions conducted as part of this grant complemented other Transnet-funded invasive control/habitat restoration efforts on South Crest; techniques developed/refined in this project are applicable to other conserved populations.
