66 
PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 64, Supplement 1 
Biogeography And Biodiversity 
Here we summarize the geographic patterns of cave biodiversity in California and recognize 
the top caves for biodiversity. As mentioned above, we have compiled biological data on 1,301 
sites, including many carbonate caves, lava tubes, sea caves, groundwater sites, and mines. At least 
1,366 taxa are recorded, including 102 terrestrial troglobites (terrestrial cave obligates), 12 sty go- 
bites (aquatic cave obligates), and 32 phreatobites (troglomorphic groundwater forms), a total of 
146 obligate subterranean species, detailed in Table 11. Of those 146 taxa, 11 are still undetermined 
beyond the level of Order or Family, and represent an uncertain number of true species, although 
some are likely new species. Half (74) of the obligates are undescribed species, comprised of 63 
troglobites, 3 stygobites, and 8 phreatobites (Table 12). Our species list includes 111 undescribed 
species of all types. 
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 Sierra Nevada. 
Sierra Nevada North has 18 single-site endemics, Sierra Nevada South has 16, and Klamath and 
Marble Mountains have 11. In contrast, Lava Flows North has but 5 single-site endemics. The lava 
flow conotylid millipede Plumatyla humerosa has the largest range of any troglobite in California 
(194 km). 
Table 13 provides statewide counts of sites with subterranean species; these counts are not 
exclusive, but are the numbers of sites with each ecological class (the same site may be counted 
again for another class). The distinction between phreatobite and stygobite is sometimes blurred: 
three caves contain phreatobites that normally occur in groundwater sites, while 11 groundwater 
sites contain stygobites that typically occur in caves. 
Table 14 shows the ranked regional counts of obligate subterranean species. Sierra Nevada 
North (SNN) has the highest number of obligate subterranean species at 41, Sierra Nevada South 
(SNS) has 32, Klamath Mountains (KM) has 18, Bay Area/Delta (BD) has 13, Coast Ranges 13, 
Lava Flows North (LFN) 11, and Mojave Desert (MD) 6. Some undescribed species seem to range 
across several regions, indicated in the table as California, Northern California, and Sierra Nevada, 
but that is not likely, and those species probably will turn out to be multiple species with further 
taxonomic study. These current rankings may partially reflect the amount of study that has gone 
into each region. However, the pattern of biodiversity in individual caves is somewhat different, 
discussed below. 
Table 15 also shows obligates, but with regional and county counts. The table shows the num¬ 
ber of obligates within each county (the same species may be counted again in other counties). 
These counts convey an impression of how the areas rank in subterranean species richness. Lead¬ 
ing counties are Calaveras in SNN (31 species); Tulare (27) in SNS; Tuolumne in SNN (23); Shas¬ 
ta in two northern regions (21, with 14 karst and 7 lava); Siskiyou in two northern regions (19, with 
12 karst and 7 lava); Santa Cruz in BD (6); SNN counties Amador (9) and El Dorado (7); SNS 
county Mariposa (5); SNN’s Placer (5); Coastal Ranges’ San Diego (7); and Napa (9) in Bay 
Area/Delta. 
Table 16 focuses on caves, stygobites, and troglobites, providing a regional view of the num¬ 
bers of sampled caves and the occupancy rate of stygobites and troglobites in the sampled caves. 
The BD region (especially Santa Cruz Karst and Napa County) has the highest occupancy (cave 
obligates/cave) at 0.88. The ranking is the natural occupancy by cave forms combined with the 
amount of field work that has been done in each region. Only two sea caves out of 800 have a 
troglobite, for example, and probably very few of the other sea caves have been searched for small 
terrestrial invertebrates. 
