Channel Islands Restoration has been working on Santa Rosa Island since 2006. Since then we have worked at dozens of project sites all in the name of restoring habitat. From removing ice plant at the shoreline near East Point to restoring the Cloud Forest atop Soledad Mountain, we've worked hard to ensure the protection and conservation of this island's rare and endemic plants and animals.
Channel Islands Restoration staff and volunteers joined other stakeholders in mapping all known populations of Yellowspine Thistle and Silverleaf Nightshade with GPS units. They then pruned the natives surrounding the invasive plants while also removing any growing fruits from the invasives in order to prepare the sites for herbicide treatment. Once the invasive plants were killed, we planted native plants in the open areas to impede invasives from resprouting.
Yellowspine thistle (Cirsium ochrocentrum) is designated by the California Department of Food and Agriculture as an "A" rated noxious weed. 1 Populations of this weed are of very limited distribution in California. In Santa Barbara County, it is only known to occur on Santa Rosa Island. Large infestations could ruin a landscape for rangeland, recreation, and wildlife habitat. - Santa Barbara Agricultural Commissioner.
Silverleaf nightshade (Solanum elaeagnifolium), also known as white horsenettle, is designated by the California Department of Food and Agriculture as a "B" rated noxious weed.2
Populations of this weed are of limited distribution in California. In Santa Barbara County it has been found on Santa Cruz Island from the Christy Barn area to the Christy airfield area and in Cebada Canyon, but is still very localized. It is found on Santa Rosa Island as well. These Channel Islands populations have received repeated treatments as part of the SBCWMA's Santa Rosa Island Noxious Weed Survey and Eradication Project. A population was found in 2009, and treated [by CIR], on the San Marcos Foothills. Additional historical collections have been made at the Bishop Ranch near Goleta, along a Solvang roadside, along Meigs Road in Santa Barbara, and at the mouth of Rattlesnake Canyon.
1 "A" rated noxious weeds are plants of known economic importance subject to enforcement action and are the highest priority for eradication by the CDFA and the SBCWMA. Populations of this weed are of very limited distribution in California. In Santa Barbara County, it is only known to occur on Santa Rosa Island. Large infestations could ruin a landscape for rangeland, recreation and wildlife habitat.
2 "B" rated noxious weeds are plants of know economic importance subject to enforcement action and are a high priority for control by the CDFA and the SBCWMA.
Santa Barbara Agricultural Commissioner.
During the ranching era deer and elk were introduced to the island for sport hunting. These non-native herbivores easily grazed upon the endemic island plants which had not adapted to withstand grazing.
As management of the island was nearly finished transferring from the ranchers to the National Park Service, CIR stepped in to install fencing and cages around important plant populations and around newly planted natives around our restoration sites.
When deer and elk were completely removed from the island we underwent the arduous task of removing all of our now-obsolete fencing.
Channel Islands Restoration assisted park biologists with their work to conserve the endangered and endemic Phacelia insularis var. insularis. We raked large areas of dead nonnative grass detritus in an effort to increase fertilization and germination of the Phacelia. The experimental section had a slightly higher success rate when compared to a control, but it wasn't substanial.
We also propagated and planted a species of extremely rare and endemic Dudleya at China Camp on the southwest side of the island.
Ice plant (specifically Carpobrotus edulis here) is such a ubiquitous invasive plant on the mainland that eradication seems almost futile. The unique factor in restoring island habitat is that with dedication to eradicating resprouts and taking strong preventative measures for all traffic coming onto the island to be clean of invasive seeds, we can actually completely remove invasives from these delicate island ecosystems.
Why remove ice plant in the first place? I'll let the California Invasive Plant Council answer that:
The project goals are to slow erosion on the island and replace the lost fog-water harvesting vegetation, such as the rare island oak trees. During the volunteer trips, erosion control devises were built and installed in areas on the island that have been severely impacted by the overgrazing of non-native species.
Volunteers sorted, loaded and transported multiple stake bed truckloads of wood to the restoration sites that were used in the construction of check dams and silt fences in eroded gullies. Volunteers pounded in rebar and posts as structural support for the dams and material silt fences.
Organic-fiber wattles and rock bags were filled and assembled, transported, and installed on the island’s ridges and around groves. Staff and volunteers put in long but satisfying hours, knowing they were assisting in a unique and vital restoration project, and enjoying the spectacular island setting and work group camaraderie.
For more information, Channel Islands National Park has a great page on this project. They have a lot more time and money than us...