Survey, Study, and Propagation of Rare and Special Plants from the Otay Mountain Wilderness by the San Diego Botanic Garden

Nestled against the U.S. border with Mexico in southeastern San Diego, the Otay Mountain area is home to more than 50 rare taxa of native plants, many of which are endemic to this region and poorly represented in ex situ conservation collections. Building upon early successes in the San Diego Botanic Garden’s (SDBG) fledgling science and conservation program, such as propagating the first acorns from Quercus cedrosensis in the U.S., SDBG worked to develop an ambitious project emphasizing study of endangered species through a range of conservation horticulture techniques and strategies, including genomic analysis, as a way to guide and benefit future restoration efforts for the target species and other rare native plants. SDBG staff will spend 2022 and 2023 intensively surveying for, mapping, collecting from, and propagating ten endangered species in the Otay Mountain Wilderness area as part of a conservation partnership with the Bureau of Land Management. Arctostaphylos otayensis, Baccharis vanessae, Brodiaea orcuttii, Calochortus dunnii, Clarkia delicata, Ceanothus otayensis, Comarostaphylis diversifolia subsp. diversifolia, Hosackia crassifolia var. otayensis, Lepechinia ganderi, and Monardella hypoleuca subsp. lanata are all listed as 1B species by the California Native Plant Society. Several of these only grow in the immediate vicinity of Otay Mountain in the U.S., while others represent the northernmost or southernmost extent of a taxon’s natural range. SDBG staff are scouring every nook and cranny of this mountainous wilderness while collecting GIS data about population distribution, environmental factors, and threats related to each of these species. Herbarium vouchers and seedbank accessions and other propagules are also being gathered to supplement existing collections and bolster scientific understanding in coordination with other gardens and institutions such as the San Diego Natural History Museum and Salk Institute for Biological Studies.