Abstract:
Hidden biodiversity is revealed in this study of California's subterranean fauna, which contains distinctive elements that differentiate it from other North American regions. Since 1975, the rate of discovery of new species has accelerated with funded projects in most of the important cave areas of the state, including our own studies. Here we compile all available biological records for subterranean sites in California dating back to 1840.
California's karst is primarily comprised of small outcrops of marble or limestone with thousands of caves. Additionally, lava and ash flows, tens of thousands of mines, hundreds of sea caves on the mainland coast and islands, and extensive groundwater systems provide habitat for subterranean life.
At least 4,600 caves of all types are known in California, of which 22% have been biologically sampled. We summarize 1,301 biological sites, and analyze data from 998 caves: (693 karst caves and features, 181 lava tubes, and 124 sea caves), 143 groundwater sites, and 160 mines and tunnels.
The richest regions for obligate subterranean species are the Sierra Nevada, Klamath Mountains, and lava flows in the northern portion of the State. The high number (72) of single-site endemic species is indicative of the insular distribution of karst, large differences in elevation, and the many river systems cutting across the state's mountain ranges.
In our database 1,366 taxa are recorded; 134 were determined to Family or higher taxa only. There are 102 troglobites (terrestrial cave obligates), 12 stygobites (aquatic cave obligates), and 32 phreatobites (obligate groundwater forms). Of those 146 obligate subterranean taxa, 11 are still undetermined beyond Order or Family, and represent an uncertain number of distinct species, although some may be more than single new species. Our species list include 109 new (currently undescribed) species of all types, including 72 obligate subterranean species: 61 troglobites, 3 stygobites, and 8 phreatobites, significantly adding to the knowledge of California's biodiversity.