Phreatic is a term used in hydrology to refer to aquifers, in speleology to refer to cave passages, and in volcanology to refer to a type of volcanic eruption.
The Edwards Aquifer is one of the most prolific artesian aquifers in the world. Located on the eastern edge of the Edwards Plateau in the U.S. state of Texas, it is the source of drinking water for two million people, and is the primary water supply for agriculture and industry in the aquifer's region. Additionally, the Edwards Aquifer feeds the Comal and San Marcos Springs, provides springflow for recreational and downstream uses in the Nueces, San Antonio, Guadalupe, and San Marcos river basins, and is home to several unique and endangered species.
Aconitum noveboracense, also known as northern blue monkshood or northern wild monkshood, is a flowering plant belonging to the buttercup family (Ranunculaceae). Members of its genus (Aconitum) are also known as wolfsbane.
The Hine's emerald is an endangered dragonfly species found in the United States and Canada. Populations exist in Illinois, Michigan, Missouri, Ontario, and Wisconsin. Larvae are found in shallow, flowing water in fens and marshes, and often use crayfish burrows. Major threats to the species include habitat loss and alteration, and the species is legally protected in both the United States and Canada.
The Alabama cavefish is a critically endangered species of amblyopsid cavefish found only in underground pools in Key Cave, located in northwestern Alabama, United States in the Key Cave National Wildlife Refuge. It was discovered underneath a colony of gray bats in 1967 by researchers Robert A. Kuehne and John E. Cooper and scientifically described in 1974.
The Georgia blind salamander is a species of salamander in the family Plethodontidae. It is endemic to the south-eastern United States where its natural habitats are inland karsts, caves and subterranean habitats. It is listed as "Endangered" by the IUCN and is threatened by habitat loss.
The Shenandoah salamander is a small, terrestrial salamander found exclusively in Shenandoah National Park in Virginia. The Shenandoah salamander inhabits a very small range of land on just three mountain peaks. Due to the small habitat range, interspecies competition, and climate change, the population of the Shenandoah salamander is vulnerable to extinction. Mitigating human effects on the habitat of the species will be essential in attempting to preserve and grow the population.
The Comanche Springs pupfish is a species of pupfish in the family Cyprinodontidae. It is endemic to Texas, and is now found only in spring-fed pools near Balmorhea, a small town in West Texas.
Assiminea pecos is a rare species of snail in the family Assimineidae known by the common name Pecos assiminea. It is native to New Mexico and Texas in the United States. Specimens known from Mexico are now treated as members of a separate species, Assiminea cienegensis. The Pecos assiminea was federally listed as an endangered species of the United States in 2005.
Epioblasma brevidens, the Cumberlandian combshell, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae. This species is endemic to the United States, found mainly in the states of Tennessee and Virginia. This mussel resides in medium-sized streams to large rivers. The combshell is an endangered species and protected under the Endangered Species Act of 1973 (ESA). The combshell is threatened by habitat modifications and pollution.
Cambarus zophonastes, also known as the Hell Creek Cave crayfish, is named for its original location of discovery, Hell Creek Cave. It is also found in other similar habitats in Stone County and Marion County, Arkansas. These habitats include springs and caves such as Nesbitt Spring Cave in Stone County. C. zophanastes is critically endangered according to the IUCN. C. zophanastes is also protected by the ESA as an endangered species. Currently conservation efforts focus on monitoring populations, reducing disturbances, and monitoring water quality. More research has to be conducted to better understand and conserve the species.
Gammarus acherondytes, the Illinois cave amphipod, is a species of crustacean in the family Gammaridae. The crustacean is endemic to the Illinois Sinkhole Plain of Monroe County and St. Clair County, in southwestern Illinois, including Illinois Caverns State Natural Area.
Lirceus usdagalun is a rare species of crustacean known by the common name Lee County cave isopod. It is endemic to Virginia in the United States, where it is known from a single network of karst cave systems in Lee County. It is threatened by a number of processes. It is a federally listed endangered species of the United States, and is assessed as "endangered" by the International Union for Conservation of Nature.
Palaemon cummingi, known as the Squirrel Chimney Cave shrimp or the Florida cave shrimp, is a threatened species of cave-dwelling shrimp in the family Palaemonidae. P. cummingi has been observed in one sinkhole called Squirrel Chimney in Alachua County, Florida near Gainesville. Although exact numbers are unknown, it is speculated that the current P. cummingi population is very small.
Stygobromus pecki, the Peck's cave amphipod, is a rare species of crustacean found in four cavern areas of southwestern Texas in the United States. It is a federally listed endangered species in the United States and is also listed as Endangered on the IUCN Red List. Because of the species' limited geographical distribution, not much information on S. pecki is known. As of April 2022, there is no available 5-year review, Species Status Assessment, or recovery plan for the species. However, the Edwards' Aquifer Habitat Conservation Program (EAHCP), with the support of the U.S. Fish and Wildlife Service (UFWS), has been attempting to further study and promote conservation of S. pecki.
The Tooth Cave ground beetle, Rhadine persephone, is an endemic beetle that lives only in karst caves in Texas. These arthropods belong to the family Carabidae. The United States government considers these beetles endangered because they are only found in a single cave system. If these caves are destroyed, this beetle will likely go extinct. The cave system is currently threatened by pollution, urban development, and invasion by fire ants.
The spring pygmy sunfish, Elassoma alabamae, is a species of pygmy sunfish endemic to springs in northern Alabama. It was historically known to occur in springs in North Alabama along the Tennessee River in Limestone and Lauderdale counties. The spring pygmy sunfish was first discovered in Cave Spring in Lauderdale County, Alabama in 1937 but in 1938, this site was flooded by the creation of the Pickwick Reservoir. The spring pygmy sunfish was considered extinct until its rediscovery in the Beaverdam Spring complex in 1973 by researchers from the University of Tennessee.
Rhadine infernalis is a species of troglobitic beetle of the family Carabidae. They are endemic to the county of Bexar, Texas. Within this county, R. infernalis has been found in 39 caves. There are 2 named subspecies of R. infernalis: R. infernalis infernalis and R. infernalis ewersi. There is a third possible subspecies that has not been officially described. R. infernalis was classified in 2000 as endangered under the IUCN Endangered Species Act of 1973, along with 8 other karst invertebrates in the same region. It has the widest known range of the endangered karst invertebrates.
The Tooth Cave pseudoscorpion(Tartarocreagris texana) is a small cave-dwelling arachnid of the family Neobisiidae. The species was originally assigned to the genus Microcreagris, and then reassigned to Austalillocregris before arriving at its current genus, Tartarocreagris. The Tooth Cave pseudoscorpion has a small geographic distribution, known to occur in only two caves in Travis County, Texas. Additionally, it is tentatively identified in two nearby caves in Texas, but more research is necessary to accurately define the range where the species lives. There is little known about the biology, life cycle, and life history of the Tooth Cave pseudoscorpion due to a lack of research and study. Because of this, the Tooth Cave pseudoscorpion is listed on the IUCN Red List as data deficient. Under the Endangered Species Act, the Tooth Cave pseudoscorpion is listed as endangered. Recovery plans for the species focus mostly on preserving the karst ecosystem that the pseudoscorpions live in, especially including lessening human impacts on the environment.
Batrisodes venyivi, also known as Helotes mold beetle, is an eyeless beetle in the family Staphylinidae. They are found exclusively in the dark zones of caves in the Southwest region of Texas. More specifically, they have been found in eight caves throughout Bexar County, Texas. Similar species include the eight other Bexar County invertebrates, such as Rhadine exilis or Rhadine infernalis. All nine of these species are protected under the Endangered Species Act. Despite the efforts of a small number of researchers, the logistical challenges of accessing this habitat greatly limit the amount and type of information. Very little is known of the species' behavior, population trends, or general ecology.
