Obligate cave fauna of the 48 contiguous United States

We assembled a list of obligate cave-dwelling species and subspecies, their county distribution, and their provisional global conservation rank. A tot al of 927 species and 46 additional subspecies in 96 families exclusively f rom cave and associated subterranean habitats have been described in the 48 contiguous states of the United States. The terrestrial (troglobitic) spec ies are concentrated in northeast Alabama (especially Jackson County), with other concentrations in Kentucky, Texas, Virginia, and West Virginia. Only 23 counties, comprising less than 1% of the land area of the 48 contiguous states, account for over 50% of the terrestrial species and subspecies. Th e aquatic (stygobitic) species are concentrated in Hays County, Texas, with other concentrations in Florida, Oklahoma, Texas, Virginia, and West Virgi nia. Only 18 counties, comprising less than 1% of the land area, account fo r over 50% of the aquatic species and subspecies. Endemism is high, with 54 % of the species known from a single county. Approximately 95% of the speci es are listed by The Nature Conservancy as vulnerable or imperiled in the U nited States. These cave species comprise 50% of all vulnerable or imperile d species listed in databases of the Natural Heritage Program. Less than 4% of these subterranean species have federal status. Conservation can best b e accomplished through habitat protection, which must include protection of the associated surface habitat.