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Irvine Ranch Conservancy Conducts Rare Plant Restoration in Crystal Cove State Park

Bluffs in Crystal Cove State Park

Orange County’s coastal wildlands are made up of rich and diverse plant communities that include rare species only found in southern California. These communities have been impacted in many areas by former grazing, invasive plant species, and development. In response, Irvine Ranch Conservancy (IRC) is partnering with California Department of Parks and Recreation (DPR) and Orange County Waste and Recycling (OCWR) to restore critical coastal habitat in Crystal Cove State Park (CCSP), with a special focus on rare plants.

The project is intended to restore 7.5 acres of degraded coastal bluff and sage scrub and will be implemented over 7-8 years. The first 2-3 years are spent preparing the site, which involves weed control aimed at depleting the non-native seed bank. Once the seed bank has been sufficiently depleted, a diverse suite of native plant species will be installed via seed and container plants. For this project, IRC has added several rare plant species to the plant palette, including Coulter’s saltbush, paniculate tarplant, cliff spurge, vernal barley, California box thorn, Orange County Turkish-rugging, and San Diego ground-cherry, all of which are known to occur in the park.
Seeds for these rare species are collected from populations within the park, following strict protocols aimed at capturing the genetic diversity of the population and preventing over-collection. Collections are then sent to California Botanic Garden (CalBG), who IRC has enlisted to assist with seed bulking and container production. Their knowledgeable staff will work to determine best practices for germinating and growing each species, while carefully tracking the genetic lines throughout the growing cycle. “Maintaining genetic diversity is always a priority when producing plant materials for restoration, but when working with rare plants it is especially important” said IRC Program Director Matt Garrambone. “California Botanic Garden’s staff are experts in this, which is why we’re so happy to have their help on this project”.

Once the seed and container plants are ready, they will be returned to IRC and installed on site during the winter of 2022-23. Germination and establishment will be carefully monitored in the field to determine the success of these rare plant introductions. Weeds will be managed for multiple years to reduce competition with native plants and promote establishment of a diverse and resilient native plant community that can support wildlife, resist future weed invasions, and be enjoyed by visitors to the park in years to come.