74 
PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 64, Supplement 1 
B| (see Methods) was used to rank 38 top caves in descending order for a final list of 20 caves 
(Table 17). Only the top 20 are given in Table 17 because of our concerns over low sampling in the 
others. B 2 , a similar measure of biodiversity, is calculated as SR x T x SST (SST is the number of 
single-site troglomorphic species in the cave). Out of the top 20 caves thus ranked, only 2 fell 
below 20 th in position by using B 2 instead of B,. Therefore, B 2 and single-site endemics are high¬ 
ly predictive of overall biodiversity. Caves with high SR tend to also have more obligate cave 
species and SSTs, but not always. For example, McLean’s Cave, Tuolumne County, had 98 species, 
but only 4 troglobites and no endemics, but it ranks 10th with B l and 37 th with B 2 . 
With either B , or B 2 the top 20 caves are concentrated in SNS, BD, SNN, and KM (see Table 
17 for regional abbreviations). Although SNN has more troglomorphic species, SNS has higher 
biodiversity and endemicity in individual caves. The top five caves are Clough Cave (SNS), 
Samwel Cave (KM), Empire Cave (BD), Clay Cave (BD), and Lilbum Cave (SNS). Complete 
species lists for these top five caves are given in Tables 18-22, and they are discussed in Ecology 
below. 
The rankings of the top 20 caves may have been influenced by sampling intensity and mois¬ 
ture conditions at the time of sampling. Cave faunas are like soil faunas, and apparent abundances 
of cave creatures change with moisture conditions. Many of the small arthropods retreat into cracks 
during dry conditions. Most of California has an annual dry/wet cycle (Mediterranean climate) and 
is prone to severe droughts. The first intensive cave biology studies in the Stanislaus River basin 
in 1977 were during a drought, and it was not until studies during wetter conditions in 1978-1979 
that many Banksula populations and other fauna were discovered in some of the caves (McEach- 
em and Grady 1978; Elliott 1978; Rudolph 1979). 
In California caves we find species with boreal and tropical origins, sometimes in the same 
vicinity. Boreal forms include some rhagidiid mites, which may be relicts related to species much 
farther north, even subpolar areas (Zacharda and Elliott 1982, 1985), although some species are 
found in Mexico (Elliott and Strandtmann 1971; Zacharda 1980). Grylloblattids, boreal forms, 
reach their most southern localities in May’s Cave and Lilburn Cave, Tulare Co. Upper Shoshone 
Cave is the site of the second-most northern schizomid record in North America; schizomids are a 
basically tropical arachnid Order. The Arizona and California species are more closely related to 
Asian schizomids than to those elsewhere in the New World. These occurrences reflect past isola¬ 
tions of ancestors in caves and crevices caused by glaciation, warm periods, and droughts. 
To summarize, high biodiversity caves are found in many regions of California, and tend to be 
those caves with many species found during multiple trips by cave biologists, but a few caves also 
have up to 11 troglomorphic species and up to 4 single-site endemics. We examined the possible 
relationship between biodiversity and elevation of caves, but found no significant linear regression. 
The 9 SNS Region caves in the top 20 caves (Table 17) are at higher elevations than other 
regions, but they may have also have good depth and moisture. They are near the edges of former 
alpine glaciers. 
Figure 113 (graph; see p. 77) is a scatterplot and linear regression of SR (species richness) for 
221 caves vs. vertical cave depth. Although the slope of the regression is low, the positive regres¬ 
sion is statistically significant (two-tailed test, p = 0.008). However, the true ecological relationship 
may be between SR (species richness) and moisture and humidity rather than cave depth. Shallow 
caves may tend to be warmer and drier. A linear regression analysis of T (troglobites) vs. cave depth 
in 104 caves was not significant, but most caves had few troglobites, so this analysis begs for a 
larger dataset. 
The only ash and lava caves in the top 20 are Clay Cave, BD region, and Subway Cave, LFN 
region. Tulare County (SNS) has 7 caves in the top 20 at higher elevations of 500-1600 m, but the 
