Siskiyou Mariposa Lily
Siskiyou mariposa (Calochortus persistens) lily is a pink flowering perennial herb that is endemic to Bald Mountain near Ashland, Oregon, and Gunsight Peak and Diggles Gulch in Siskiyou County, California. The lily is found on north-facing slopes or ridge-tops with little vegetation cover, shallow, dry, acidic and rocky soils, and in yellow pine or coastal coniferous forests.
The known populations on Bald Mountain, Oregon are believed to be locally extinct. Threats to the continuance of Siskiyou mariposa lily on its marginal remaining territory in California include: fire suppression, increased fuel loading due to fire suppression, competition with native and exotic species, fragmentation by roads, construction of radio tower facilities, spreading of weeds through recreational use of habitat, tree plantations, bulb collecting and predation by deer, rodents and insects prior to seed dispersal. Fire suppression has led to increased shading of habitat and increased fuel loading. Curl-leaf mountain mahogany and Oregon grape are the primary species shading out Siskiyou mariposa lily. High intensity fires caused by increased fuel loading could wipe out entire populations.
The greatest threat to Siskiyou mariposa lily is dyer’s woad (Isatis tinctoria), an invasive species that affects 90% of known Siskiyou mariposa lily habitat. The dense rosettes of dyer’s woad prevent seedling establishment, increasing competition for space, water and nutrients.
Siskiyou mariposa lily is currently listed as a “rare” species under the California Native Plant Protection Act, which prohibits collecting, selling or picking the flower or bulb. Protection under this Act is insufficient because it does not protect the plant from habitat or land use change, or habitat invasion from exotic species. In August 2001, KS Wild petitioned to list the Siskiyou mariposa lily as “Endangered” by the United States Fish and Wildlife Services under the Endangered Species Act.