Biology of the Caves at Sinkhole Flat, Eddy County, New Mexico

Sinkhole Flat, as the name suggests, is a region of relatively few features in southeastern New Mexico (Figure 1). There are a few arroyos and sinkholes. This study area is in the northern Chihuahuan Desert and plants are typical for this desert region which lies at about 1,000 meters elevation. The vegetation consists predominately of grasses, Opuntia, Yucca, Larrea, and Acacia. The caves at Sinkhole Flat have developed in gypsum and gypsiferous sandstone beds. Periodically, flooding during heavy rainfalls washes sand, gravel, mud, and organic debris into these caves. The larger caves apparently remain wet year-round, providing an oasis from the arid surface environment. The topography and vegetation typical of Sinkhole Flat are shown in Figures 2-3. Until now, the gypsum caves at Sinkhole Flat have received little attention by cavers or biologists. There are only two accounts that have been published (Reddell, 1965; Barr and Reddell, 1967) and both of those reports were based upon a single trip made by James Reddell and William Russell in December 1964. Records from other caves in the region (Barr and Reddell, 1967; Elliott, 1978; Welbourn, 1976, 1978) suggest that there might be a much richer fauna at Sinkhole Flat than the 12 species documented by Barr and Reddell (1967). The flora and microbiology of caves in southeastern New Mexico have been essentially ignored until recently (Cunningham et al., 1995). Thorough studies of cave biology require extensive training, considerable time (both field and laboratory), and specialized equipment. We did not collect fungal or microbiological samples. It is not just caves at Sinkhole Flat, but gypsum caves in general in New Mexico that have been little studied. Other than anecdotal remarks found in trip reports and mention of vertebrates, few notices of cave biology of gypsum caves have appeared. With the growing concerns about biodiversity and potential loss of faunas and floras, it is hoped that individuals who have unpublished records from New Mexico caves will make them available for others, thus reducing duplicated effort. Future studies should be directed at the gypsum caves. While these caves are generally not as attractive and respected Figure 1. Location map of the drainages and sinks of Sinkhole Flat, New Mexico. The roads and other identifying structures have been excluded. Precise cave locations can be obtained from the Bureau of Land Management, Roswell, New Mexico. Elevations are in feet.