U.S. DEPARTMENT OF THE INTERIORBUREAU OF LAND MANAGEMENT
Barstow Field Office Cave Monitoring Project
The BLM Barstow Field Office is conducting first-time wildlife inventories for mud caves that are the only known habitat of a scorpion species – among other rare or unique species.
Earlier this year, the Barstow Field Office successfully applied for a small grant from the BLM National Office, to support a Cave and Karst-related field project. The primary objective for our funded project was to conduct first time inventories of the mud caves in the Shoshone area and the Pisgah Crater lava tubes. Also, this project provided an updated inventory of the Shoshone Caves. These data will provide important information relevant to the management of these resources, fulfill management objectives of approved Bureau of Land Management (BLM) plans, and ultimately contribute to the Faunal Biodiversity Assessment of Subterranean Habitats of California being conducted by Dr. G.O. Graening of the California State University, Sacramento. Significant findings, such as discovery of new species, will be published in scientific journals as appropriate.
The Shoshone Caves are the only known habitat for the Shoshone Cave whip-scorpion (Trithyreus shoshonensis). This species is considered “sensitive” by the BLM. The Shoshone Cave (Whip-scorpion Habitat) Wildlife Habitat Management Plan indicates that the highly restricted distribution of this endemic species, which is heavily reliant upon a moist environment provided by a thermal spring at the bottom of the cave, and its apparently low population numbers “makes its continued existence without some form of protective management extremely precarious.” Prior to this survey, no individuals of this species have been found since their original discovery in 1971 and a 1990 inventory concluded that this species is “probably extinct but that there should be follow-up intensive surveys.”
The Shoshone Cave (Whip-scorpion Habitat) Wildlife Habitat Management Plan indicates that caves in this area are fissured in dark gray Cambrian limestone formations which are heated by thermal groundwater. Some researchers maintain that the whip-scorpion is totally dependent on warm, moist caves, which protect them from the freezing winters prevailing in the area. The underground hydrology of the area is not well known and is the subject of an intensive multi-year investigation being carried out by the United States Geological Society funded by BLM and other partners. While the Shoshone Caves are outside of the Amargosa River Area of Critical Environmental Concern (ACEC) and Amargosa Wild and Scenic River (WSR) planning areas proper, the caves close proximity and the fact that the caves are just up-stream of the ACEC/WSR suggest that there may be a hydrological connection between the resource areas. (text continues below)
The invertebrate population of the Shoshone Mud Caves and Pisgah Lava Tubes was currently unknown prior to these surveys. These surveys provided the first glimpse into the invertebrates living in these caves. Both the Shoshone Mud Caves and Pisgah Lava Tubes are dry and do not appear to be associated with water supplies, yet a few invertebrates manage to survive in these caves.
The early results from the surveys are encouraging. Four individual Shoshone Cave Whip-scorpions were detected during the field survey, allaying the concern expressed by earlier surveyors that this species may be extinct. Also, Shoshone Cave Harvestman (Texella Shoshone) and Shoshone Cave Cricket (Ceuthophilus sp. nov.), which are endemic to the Shoshone Caves, were observed. Of the caves inventoried, other rare animal occurrences included several species of beetles. In the Pisgah Crater lava tubes, in the Tecopa Soil Pipes, and in the Upper and Lower Shoshone Caves, darkling beetles of the genera Eschatomoxys, Eleodes, and Schizillus were found. Some of these may be new site or county records. An interesting beetle (Rhadine sp.) was found in one of the soil pipe caves that may be a new site or county record, or a new species. There is also a possibility that a barklice species (Psocoptera) found in the soil pipe caves may be rare or unique. The Shoshone Cave Beetle (Rhadine sp. nov.), a new species endemic to the Shoshone Caves, was not detected during the surveys. The researchers are continuing to evaluate these preliminary findings and will provide BLM with future reports and publish findings as warranted. Final conclusions and recommendations for Barstow Field Office caves are forthcoming and will be used to insure the continued existence of these unique subterranean creatures.
A big thank you goes out to Dr. G.O. Graening and his expert crew for donating their time to accomplish this important,survey effort.
- Chris Otahal, Wildlife Biologist, BLM Barstow Field Office (September 2012)