Protecting endangered species and wild places of western North America and the Pacific through science, policy, education, and environmental law. The Bay Checkerspot Butterfly was originally listed as Threatened under the ESA in 1987. Critical habitat was first proposed in the 1980's for the species but was subsequently withdrawn.
Critical habitat includes all areas necessary for the survival and full recovery of the species.
It is protected from federal projects for permits which would destroy or adversely modify the habitat. We are hopeful that today's habitat designation will help turn the tide toward recovery for the species. The Bay Checkerspot Butterfly depends on host plants which grow primarily in grasslands on serpentine soils, a bluish-green soil type that is naturally highly mineralized, high in magnesium, and low in nitrogen and calcium. This specialized soil system is very valuable biologically because it supports a high percentage of California's endemic species. Unfortunately, the majority of the Checkerspot's serpentine soil habitat in the Bay area has been destroyed.