CONSERVATION HISTORY AND STATUS OF THE ENDANGERED SANTA BARBARA ISLAND LIVEFOREVER—DUDLEYA TRASKIAE

Santa Barbara Island liveforever (Dudleya traskiae (Rose) Moran (Crassulaceae); hereafter DUTR) is a succulent perennial plant endemic only to Santa Barbara Island. Once thought to be extinct in the wild, due primarily to impacts from anthropogenic activities, DUTR was listed as Federally and State endangered in 1978 and 1979, respectively. We reviewed past surveys and conservation efforts to inform and evaluate more recent restoration actions. Between 2019 and 2022, we propagated and outplanted over 2000 DUTR individuals from seven separate colonies on Santa Barbara Island. Overall individual survival 1-yr post planting was 52% (n = 817). To assess herbivory impacts to outplants, we protected 185 plants using hardware cloth cages. Caged plant survival was greater (88%; n = 185) compared to uncaged plants (41%; n = 632). When outplanting DUTR, consideration should be given to cage plants to increase survival, especially in years with elevated Deer Mouse (Peromyscus gambelii) abundance or drier conditions when herbivory is likely greater. Population surveys were conducted in 2020–2021 and 2024 utilizing traditional ground survey methods as well as initiating the first known aerial photographic survey for DUTR. We estimate a minimum of 3800 DUTR on Santa Barbara Island; more than a 460% increase over the baseline count reported in 1984. Ground and aerial surveys complimented each other, though small variations did occur. Ground surveys appeared to better detect smaller DUTR, while aerial surveys were the only method capable of surveying the large cliff colonies. We attribute the increase over baseline population counts to aerial photographic surveys at cliff colonies that previously had not been adequately surveyed. We recommend a combination of periodic (i.e., minimum of every 5yr) ground and aerial photographic surveys to effectively monitor DUTR. Further research is needed to determine and define habitat requirements and map potential suitable habitat as well as determine if genetic variation exists between island colonies which could help inform future conservation actions.