Death Valley freshwater ecoregion

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The Death Valley freshwater ecoregion is a freshwater ecoregion in the western United States. It consists of endorheic rivers, lakes, and springs in the drainages of the Owens, Amargosa, and Mojave Rivers, in central-eastern California and southwestern Nevada. [1]

Contents

Most of the ecoregion lies between 610 and 1,220 meters elevation. It consists of north–south trending mountain ranges that rise along fault zones, separated by sedimentary basins. The ecoregion reaches to the peak of Mount Whitney (4,421 metres (14,505 ft)) in the Sierra Nevada, and descends to the Badwater Basin in Death Valley, which is the lowest point in North America at −86 metres (−282 ft). [2]

Fauna

The ecoregion is home to several endemic species and subspecies of fish, some of which have very limited ranges. Several are adapted to extreme environments. The small and isolated ranges and populations of many native species and subspecies make them particularly vulnerable to extinction.

There are four endemic species of pupfish, the Owens pupfish (Cyprinodon radiosus), Devil's Hole pupfish (Cyprinodon diabolis), Cyprinodon nevadensis , and the Death Valley pupfish (Cyprinodon salinus). C. nevadensis has five recognized subspecies and the Death Valley pupfish has two. The Death Valley pupfish live at the lowest elevations in Death Valley, where summer temperatures can reach 130 °F (54 °C). [2]

The Devil's Hole pupfish is found only in a single spring-fed limestone cavern in Ash Meadows, California, and at 23 square yards (19 m2) has the smallest known range of any vertebrate species. [2]

The Owens sucker (Catostomus fumeiventris) is endemic to the Owens River basin, and has been introduced to June Lake in the Mono Lake basin as well as the Santa Clara River in coastal Southern California. The ecoregion is home to endemic subspecies of Tui chub (Gila bicolor), and three endemic subspecies of speckled dace (Rhinichthys osculus). The endemic Ash Meadows killifish (Empetrichthys merriami) is thought to be extinct. [2]

Conservation and threats

For over a century the ecoregion's rivers and streams have been altered by water diversion for agriculture and cities and groundwater extraction. Construction of the Los Angeles Aqueduct in the early 20th century diverted Owens Valley and Mono Lake headwater streams to coastal Los Angeles, hundreds of miles south, and desiccated the Owens River.

Introduced species also threatened native and endemic species.

Protected areas

Protected areas include Ash Meadows National Wildlife Refuge, which encompasses a desert oasis of over 30 springs and seeps that cover an area of 756 km2, and is home to the Devil's Hole pupfish. [2] Death Valley National Park protects the Amargosa River basin and the springs and caverns of the Death Valley region.

See also

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<span class="mw-page-title-main">Death Valley pupfish</span> Small endangered fish native to Death Valley, California

The Death Valley pupfish, also known as Salt Creek pupfish, is a small species of fish in the family Cyprinodontidae found only in Death Valley National Park, California, United States. There are two recognized subspecies: C. s. salinus and C. s. milleri. The Death Valley pupfish is endemic to two small, isolated locations and currently classified as endangered.

<span class="mw-page-title-main">Amargosa Valley</span>

The Amargosa Valley is the valley through which the Amargosa River flows south, in Nye County, southwestern Nevada and Inyo County in the state of California. The south end is alternately called the "Amargosa River Valley'" or the "Tecopa Valley." Its northernmost point is around Beatty, Nevada and southernmost is Tecopa, California, where the Amargosa River enters into the Amargosa Canyon.

<span class="mw-page-title-main">Tecopa pupfish</span> Extinct subspecies of fish

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<span class="mw-page-title-main">Ash Meadows National Wildlife Refuge</span> Protected area in the Amargosa Valley of southern Nye County, Nevada

The Ash Meadows National Wildlife Refuge is a protected wildlife refuge located in the Amargosa Valley of southern Nye County, in southwestern Nevada. It is directly east of Death Valley National Park, and is 90 mi (140 km) west-northwest of Las Vegas.

<span class="mw-page-title-main">Devils Hole pupfish</span> Rare species of fish native to Nevada, U.S.

The Devils Hole pupfish is a critically endangered species of the family Cyprinodontidae (pupfishes) found only in Devils Hole, a water-filled cavern in the US state of Nevada. It was first described as a species in 1930 and is most closely related to C. nevadensis and the Death Valley pupfish. The age of the species is unknown, with differing analyses offering ranges between one thousand and sixty thousand years. It is a small fish, with maximum lengths of up to 30 mm (1.2 in). Individuals vary in coloration based on age and sex: males are bright metallic blue while females and juveniles are more yellow. A defining trait of this species is its lack of pelvic fins. The pupfish consumes nearly every available food resource at Devils Hole, including beetles, snails, algae, and freshwater crustaceans, with diet varying throughout the year. It is preyed on by the predaceous diving beetle species Neoclypeodytes cinctellus, which was first observed in Devils Hole in 1999 or 2000. Reproduction occurs year-round, with spikes in the spring and fall. Females produce few eggs, though, and the survivorship from egg to adult is low. Individuals live 10–14 months.

<span class="mw-page-title-main">Amargosa Desert</span> Desert in Nevada and California, United States

The Amargosa Desert is located in Nye County in western Nevada, United States, along the California–Nevada border, comprising the northeastern portion of the geographic Amargosa Valley, north of the Ash Meadows National Wildlife Refuge.

<span class="mw-page-title-main">Pupfish</span> Family of fishes

Pupfish are a group of small killifish belonging to ten genera of the family Cyprinodontidae of ray-finned fish. Pupfish are especially noted for being found in extreme and isolated situations. They are primarily found in North America, South America, and the Caribbean region, but Aphanius species are from southwestern Asia, northern Africa, and southern Europe. As of August 2006, 120 nominal species and 9 subspecies were known. Several pupfish species are extinct and most extant species are listed. In the U.S., the most well-known pupfish species may be the Devil's Hole Desert Pupfish, native to Devil's Hole on the Nevada side of Death Valley National Park. Since 1995 the Devil's Hole Pupfish has been in a nearly steady decline, where it was close to extinction at 35–68 fish in 2013.

<span class="mw-page-title-main">Devils Hole</span> Spring in Nye County, Nevada, in the Southwestern United States

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<i>Cyprinodon</i> Genus of fishes

Cyprinodon is a genus of pupfishes found in waters that range from fresh to hypersaline. The genus is primarily found in Mexico, the Caribbean Islands and southern United States, but C. variegatus occurs as far north as Massachusetts and along the entire Gulf of Mexico coastline, and C. dearborni and C. variegatus are found in northern South America. Many species have tiny ranges and are highly threatened, in some cases already extinct. Cyprinodon are small; the largest reaches 10 cm (3.9 in) in length and most other species only reach about half that size.

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Cyprinodon ceciliae is an extinct species of pupfish. It was endemic to the Ojo de Agua la Presa in southwestern Nuevo Leon state in Mexico, but disappeared in 1990 due to habitat loss. The same freshwater spring system was the home of three other pupfish: Cyprinodon inmemoriam (extinct), Cyprinodon longidorsalis and Cyprinodon veronicae. Although these were from the same spring system, each was restricted to its own individual spring and associated waters. The exact spring and associated waters inhabited by the Villa Lopez pupfish were also the home of a now-extinct, undescribed species of Cambarellus crayfish. The specific name honours the daughter of María de Lourdes Lozano-Vilano and niece of Salvador Contreras-Balderas, Cecilia Contreras Lozano, who assisted on the trip on which the type was collected.

<span class="mw-page-title-main">Owens pupfish</span> Species of fish

The Owens pupfish is a rare species of fish in the family Cyprinodontidae, the pupfish. It is endemic to California in the United States, where it is limited to the Owens Valley. It is a federally listed endangered species of the United States. This pupfish is up to 5 centimetres long, the largest males sometimes longer. The male is blue-gray, turning bright blue during spawning. The female is greenish brown with a silvery or whitish belly.

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<span class="mw-page-title-main">Desert pupfish</span> Species of fish

The desert pupfish is a rare species of bony fish in the family Cyprinodontidae. It is a small fish, typically less than 7.62 cm (3 in) in length. Males are generally larger than females, and have bright-blue coloration, while females and juveniles are silvery or tan. A notable attribute of the desert pupfish is their ability to survive in environments of extreme salinity, pH, and temperature, and low oxygen content. The desert pupfish mates in a characteristic fashion, wherein compatible males and females will come in contact and collectively jerk in an s-shape. Each jerk typically produces a single egg that is fertilized by the male and deposited in his territory. Breeding behavior includes aggressive arena-breeding and more docile consort-pair breeding.

The Saratoga Springs pupfish is a subspecies of the Amargosa pupfish of the family Cyprinodontidae. The native population is endemic to Saratoga Springs, a small wetland in Death Valley National Park in the United States.

<i>Cyprinodon nevadensis</i> Species of fish

Cyprinodon nevadensis is a species of pupfish in the genus Cyprinodon. The species is also known as the Amargosa pupfish, but that name may also refer to one subspecies, Cyprinodon nevadensis amargosae. All six subspecies are or were endemic to very isolated locations in the Mojave Desert of California and Nevada.

<span class="mw-page-title-main">Lake Manly</span> Lake in Death Valley, California, United States

Lake Manly was a pluvial lake in Death Valley, California, covering much of Death Valley with a surface area of 1,600 square kilometres (620 sq mi) during the so-called "Blackwelder stand". Water levels varied through its history, and the chronology is further complicated by active tectonic processes that have modified the elevations of the various shorelines of Lake Manly; during the Blackwelder stage they reached 47–90 metres (154–295 ft) above sea level. The lake received water mainly from the Amargosa River and at various points from the Mojave River and Owens River. The lake and its substantial catchment favoured the spread of a number of aquatic species, including some lizards, pupfish and springsnails. The lake probably supported a substantial ecosystem, and a number of diatoms developed there.

<span class="mw-page-title-main">Amargosa River pupfish</span> Subspecies of fish

The Amargosa River pupfish is a member of a pupfish species complex which inhabits the watershed of ancient Lake Manly. Currently, the species inhabits two disjunct perennial reaches of the lower Amargosa River. The upstream portion is near Tecopa and passes through the Amargosa Canyon. The lower portion is northwest of Saratoga Springs, just at the head of Death Valley, where the Amargosa River turns north to enter the valley.

References

  1. Abell, Robin A. (2000). "Appendix G. Ecoregion Descriptions. Ecoregion 11. Death Valley". Freshwater Ecoregions of North America: A Conservation Assessment. Island Press. p. 177. ISBN   978-1-55963-734-3.
  2. 1 2 3 4 5 "Death Valley". Freshwater Ecoregions of the World. Retrieved 17 September 2021.

Coordinates: 36°25′N116°20′W / 36.42°N 116.33°W / 36.42; -116.33