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PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 64, Supplement 1 
should be avoided. Sealing and gating of cave and mine entrances because of safety concerns or 
perceived liability remains controversial. Many states protect owners of natural features (caves) 
from liability for injuries to visitors unless admission tickets are sold, but man-made mines are a 
different matter and the “attractive nuisance” legal liability may exist unless barriers or gates are 
installed. It has been estimated that over 39,000 abandoned mines exist in California (California 
Department of Conservation 2000), and there are ongoing programs to properly gate or seal mine 
entrances. Managers of these programs are aware of the need to provide environmentally sensitive 
gates that allow the passage of bats in mines that they occupy. In recent years mines have become 
a valuable asset for bat conservation, especially as bats have been run out of some caves by recre¬ 
ational use. Mine owners have increasingly become involved in installing bat-friendly mine gates. 
Numerous sources of pollution of the state’s waters have the potential to negatively impact 
cave faunas. Mining activities, extending back to the Goldrush, are a source of mercury and other 
pollutants, some that bio-accumulate, which can impact cave organisms, especially those higher in 
the food chain. Agricultural residues (fertilizers, pesticides, sediments) can also degrade the aquat¬ 
ic environments of caves. Inadequate treatment of wastewater, including system failures, can intro¬ 
duce an extremely diverse array of pollutants into the cave environment that can have direct toxic 
effects and/or lead to eutrophication of cave waters. This would especially apply to a biologically 
rich cave as Clay Cave in Napa County, which is near large areas of human habitation and where 
the fauna is dependent on a clean source of water. 
Disturbance from human use of caves, especially if frequent and/or by individuals lacking an 
understanding of the fragile nature of the resource, is a constant conservation concern. In Missouri 
heavily used caves, once properly gated, often showed an increase of fauna during organized 
follow-up counts (Drees 1995; Elliott and Ireland 2001). Vandalism is, unfortunately, frequent in 
California caves, and, although the overall extent is unquantified, the consequences in many areas 
are obvious to experienced cavers (Bruce Rogers, pers. comm.). However, 9 of the 20 California 
caves with the highest biodiversity have experienced significant vandalism (Table 23). Bats are 
arguably the taxon most susceptible to disturbance, especially as they are often viewed negatively 
by the public. Many examples of harm to bat populations are known (Elliott 2000b). However, all 
taxa are potentially at risk from excessive levels of disturbance. Education and limitations to 
visitation (proper gates, permits with numerical quotas, etc.) can effectively address these issues if 
the specific problem is recognized and the owners/managers take appropriate actions. 
Exotic and invasive species are a rapidly increasing threat to nearly all ecosystems worldwide. 
Caves are no exception. To date serious impacts have not been detected in California cave com¬ 
munities. However, several pathogens are on the horizon. White nose syndrome, caused by the 
exotic fungal pathogen Pseudogymnoascus destructans of European origin, has resulted in over 6 
million bat deaths in eastern North America, primarily affecting hibernating bats. The pathogen is 
rapidly spreading west across the continent, and has recently been reported in King County, Wash¬ 
ington (U.S. Geological Survey 2016a). It is only a matter of time before California bat populations 
will be impacted. The South American imported red fire ant ( Solenopsis invicta) has caused seri¬ 
ous impacts on cave faunas in Texas (Elliott 2000b). The species has now colonized California and 
the potential exists for impacts on cave faunas. Amphibians are experiencing a global extinction 
crisis from numerous factors including an array of exotic and invasive diseases (Whittaker et al. 
2013). One of these organisms, chytrid fungus ( Batrachochytrium dendrobatidis ) has been report¬ 
ed in Missouri cave amphibians (Elliott 2012). Although amphibians are not generally major com¬ 
ponents of cave faunas in California, potential impacts on the Hydromantes species are of concern. 
Because of the tremendous global trade network and lax regulation of potential introductions of 
exotic species, the impact of invasive and exotic species will undoubtedly increase in the future. 
