The Barton Springs salamander (Eurycea sosorum) is a small (up to 2.5 inches), slender, pale purplish-brown to yellowish-cream colored salamander found only in spring outlets in Barton Springs in Austin, Texas. This salamander is aquatic its entire life, depending on a constant supply of clean, flowing water from Barton Springs at a consistent temperature of 70º. The Barton Springs salamander was listed as an endangered species in 1997. Only 274 salamanders were observed during recent surveys of four hydrologically connected pools at Barton Springs.
Photo courtesy of Wyman Meinzer, USFWS
The aquifer fed waters of Barton Springs bubble up from deep underground at a consistent 70º year round. Water quality at Barton Springs, an important tourist attraction, is a critical issue for the City of Austin, which relies on the springs for part of its municipal water supply. Barton Springs is the largest spring-fed, natural bottom swimming hole in the country, and is enjoyed by over 340,000 people every year, many unaware that they are swimming with one of the most endangered vertebrate species in North America. The water that discharges at Barton Springs, the fourth largest spring in Texas, originates from the Barton Springs segment of the Edwards Aquifer.
There are more than 50 known species of animals and plants that live only in the Edwards Aquifer region and no where else in the world, placing the region on a global list of biodiversity hot spots. Each of the major Edwards Aquifer spring outlets provides an "island habitat" of pure, reliable, constant flowing water that is separated from each of the others. Life forms have evolved that are unique to each of the springs, particularly aquatic salamanders and small aquatic invertebrates. Barton Springs is also home to the recently discovered Austin Blind salamander, which lives deeper inside the aquifer. The Austin Blind salamander is uniquely adapted to a world of total darkness, lacking eyes and pigment. The Georgetown, Salado, and Jollyville salamanders are three species of aquatic salamanders found in different areas of the northern Edwards Aquifer.
Barton Springs, Austin, TX
The primary threat to the Barton Springs salamander is the degradation of the quality and quantity of water that feeds Barton Springs as a result of urban expansion over the watershed. Barton Springs is a karst aquifer, heavily influenced by the quality and quantity of runoff, particularly in the recharge zone. Increasing urban development over the area supplying recharge waters to the Barton Springs segment can threaten water quality within the aquifer. The Texas Water Commission identified the Edwards aquifer as being one of the most sensitive aquifers in Texas to groundwater pollution. Sediment run-off from construction harms the salamander by clogging its gills, causing asphyxiation, smothering eggs, reducing the availability of spawning sites, reducing water circulation and oxygen, and exposing aquatic life to contaminants that readily bind to sediments.
The decline of the Barton Springs salamander mirrors a disturbing trend of global amphibian decline linked to human causes including deforestation, ozone depletion, draining of wetlands, pollution, increased UV-B radiation, acid rain, and disease. In September 2005 the Fish and Wildlife Service released the Barton Springs salamander Recovery Plan (link to recovery plan) .
Salamanders and Pesticides Don’t Mix
Barton Springs salamanders have recently been developing strange deformities and dying of bizarre maladies. Since the Barton Springs salamander spends its entire life in water and has a thin permeable skin and external gills, it is extremely sensitive to pollutants and pesticide contamination. The U.S. Geological Survey has found six pesticides in the Barton Springs aquifer of concern to salamanders and human health: atrazine, carbaryl, diazinon, metolachlor, prometon, and simazine. And in 2002, the U.S. Fish and Wildlife Service requested that the U.S. Environmental Protection Agency enter into consultation under the Endangered Species Act regarding the impact of atrazine on the Barton Springs Salamander. Atrazine has been documented in Barton Springs at levels that warrant concern for the survival of the Barton Springs salamander and possibly also public health.
The controversial pesticide atrazine is a known endocrine disruptor, which chemically castrates and feminizes male amphibians. Atrazine has also been linked to increased prostate cancer and decreased sperm count in men, as well as higher risk of breast cancer in women. Both a trazine and carbaryl have been found to impact amphib ian s at very low concentrations. The U.S.G.S. found atrazine in Barton Springs at levels five to ten times greater than concentrations shown to cause disruption of sexual development in frogs. Studies by Dr. Tyrone Hayes at the University of California have strengthened the case for banning atrazine, the most common contaminant of ground, surface, and drinking water. (Hayes, 2004; Hayes et al, 2006)
Although numerous scientific studies have definitively linked pesticide use with significant developmental, neurological and reproductive effects on amphibians, the Environmental Protection Agency refused to initiate consultation for pesticide impacts to the Barton Springs salamander, and in January 2004 the Center and Save Our Springs Alliance filed a lawsuit against the agency for failing to consult on the impact of the six pesticides. Read a press release about the lawsuit. In August 2005 the agency settled the lawsuit and agreed to consult with the Service on the impacts of atrazine within one year and the remaining five pesticides within two years. Read a press release about the settlement.