February 28, 2011 – By Nick Engelfried
Have you ever heard of the Cockendolpher cave harvestman? How about the Braken Bat Cave meshweaver or the Comal Springs riffle beetle? These elusive invertebrates may not be household names, but they’re among nine fascinating and unique cave-dwelling insects and arachnids which the US Fish and Wildlife Service has proposed granting nearly seven thousand acres of protected habitat in Texas. Conservation groups like the Center for Biological Diversity celebrated the protection of these beetles, spiders, and harvestmen (think “daddy long-legs”) which inhabit some of the world’s least-studied ecosystems deep in underground cave systems.
The Comal Springs riffle beetle, an aquatic beetle that lives in underground springs, relies and a steady supply of clean underground water to survive. Pollution and unsustainable harvesting of Texas’ groundwater threatens the beetle’s continued existence, leading it to be designated an endangered species in 1997. However like the other cave critters recently granted new protections, the riffle beetle originally was granted habitat protections too small to ensure its survival.
In fact, the US Fish and Wildlife Service at first declined to designate any critical habitat for the Comal Springs riffle beetle and other cave-dwelling species in 1997, prompting the Center for Biological Diversity to sue for protections. In 2007, the Bush administration Fish and Wildlife Service agreed to protect one thousand acres to the imperiled species, the Center contended that was too little to prevent the extinction of many species. In 2009 the Center filed another lawsuit aimed at protecting fifteen cave species. This month the Obama administration Fish and Wildlife Service came through for nine of those species, increasing the size of the critical habitat designation to almost seven thousand acres.
“This nearly sevenfold increase in protected habitat gives these nine unique Texas species a chance at survival,” said Noah Greenwald, the endangered species director for the Center for Biological Diversity. “With just a modest restriction on urban sprawl, these species that occur nowhere else on Earth may be saved.”
Because they are dark, cold, and contain relatively few sources of nutrients, underground caves are challenging environments for most animals to live in. The challenge of surviving deep in a cave is especially great for invertebrates, which are usually too small to make regular trips above ground as do bats and some cave-dwelling birds. Still, a variety of spiders, harvestmen, beetles, crickets, crayfish, and other invertebrates have adapted to life in caves. Over time many have lost eyesight and other characteristics of their above-ground relatives, and some species are found only in a single cave or cave system.
In some ways animals must be hardy to survive in the harsh cave environment. However because cave ecosystems are very isolated, their inhabitants can be extremely sensitive to environmental change. When water is pumped out of underground aquifers for irrigation or drinking, it can deplete the underground reservoirs cave-dwelling creatures depend on to survive. Nearby development can also cause contamination and pollution of groundwater supplies, again imperiling cave invertebrates.
Critical habitat designations for cave species protect them by limiting human activity in areas where it would be most likely to affect cave ecosystems. For the nine species whose protection was announced this month, this means keeping urban sprawl from encroaching over their habitat in Bexar County, Texas. Housing developments expanding outward from the city of San Antonio would put further pressure on Edwards Aquifer and threaten to contaminate the water. Though seven thousand acres sounds like a lot, it will not dramatically impact the ability of the San Antonio area to expand. At the same time the habitat protection will help conserve some fascinating cave-dwellers.
“Most scientists believe we’re in an extinction crisis much like the one that destroyed the dinosaurs, except this time the cause is us,” said the Center for Biological Diversity’s Greenwald. “Ending this crisis and saving species is about choosing to make some places off-limits to development—there is no other way.”
Photo credit: “swimstud1386” on Flickr