Other toxins are also present and these, along with cadmium, present a danger of bioaccumulation in the food web. The loss of a colony of gray bats which inhabited Shelta Cave may have also have had an effect. Bat excrement provided food for many of the cave's aquatic species, and its loss may have caused or contributed to the population declines of these species during the 198O's. Water shortages in Huntsville, caused by increased water consumption and drought, may lower the aquifer levels in both caves. Disease and predation also threaten the cave shrimp.
Predation is normal.
However, when predation is combined with all these other threats and the species' low productive rate, it has a greater impact on the species' survival. The southern cavefish, the cave salamander, and the cave crayfish pose the greatest threats. Both of these owners are protecting the cave entrances and restricting public access. The National Speleological Society has developed a draft management plan for Shelta Cave aimed at recovering its biological resources. In addition, the U.S. Fish and Wildlife Service is conducting a water quality study of Shelta Cave, and is involved with the Geological Survey of Alabama to identify recharge areas for the aquifers of Shelta and Bobcat Caves.