The Dixie Valley toad (''Anaxyrus williamsi'' or ''Bufo williamsi'') is a
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of
toad
Toad is a common name for certain frogs, especially of the family Bufonidae, that are characterized by dry, leathery skin, short legs, and large bumps covering the parotoid glands.
A distinction between frogs and toads is not made in scientif ...
in the family
Bufonidae. It is
endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
to
Churchill County in the state of
Nevada
Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...
in the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
.
It was the first new toad species to be described from the United States since the description of the now-
extinct in the wild
A species that is extinct in the wild (EW) is one that has been categorized by the International Union for Conservation of Nature as known only by living members kept in captivity or as a naturalized population outside its historic range due ...
Wyoming toad (''A. baxteri'') about 49 years prior.
Taxonomy
It was formerly considered an isolated population of the common
western toad (''A. boreas'') until physical and genetic analyses found it to be a separate species, and described it as such in 2017. It is descended from an ancestor that inhabited the large lakes and wetlands that covered the
Great Basin
The Great Basin is the largest area of contiguous endorheic basin, endorheic watersheds, those with no outlets, in North America. It spans nearly all of Nevada, much of Utah, and portions of California, Idaho, Oregon, Wyoming, and Baja California ...
in the
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
until the receding water isolated the different populations, leading to speciation.
Distribution and habitat
The Dixie Valley toad is found only in a small complex of vegetated spring-fed marshlands in
Dixie Valley
The Dixie Valley is an endorheic basin which had plentiful ground water (free-flowing artesian wells) around which ranches were built. Prior to the US Navy TOPGUN school moving from California to Nevada, the valley was purchased in 1995 for $10 ...
, one of the hottest and most geothermally active systems in the region. The surrounding areas are largely arid land with few aquatic resources, isolating ''A. williamsi'' from the rest of the world.
Description
It can be physically distinguished from the western toad by the scattered gold-colored flecks that cover its olive body, and is also the smallest member of the ''A. boreas''
species complex in the region.
Threats
While it is considered locally abundant within its extremely small range, environmentalist groups believe that it may be threatened by plans to build a
binary cycle[ ]geothermal power
Geothermal power is electrical power generated from geothermal energy. Technologies in use include dry steam power stations, flash steam power stations and binary cycle power stations. Geothermal electricity generation is currently used in 2 ...
plant, alleging that operations may degrade the marshland that it lives in by drying up the springs.Bureau of Land Management
The Bureau of Land Management (BLM) is an agency within the United States Department of the Interior responsible for administering federal lands. Headquartered in Washington DC, and with oversight over , it governs one eighth of the country's la ...
(BLM) prior to permitting approval, required by the National Environmental Policy Act
The National Environmental Policy Act (NEPA) is a United States environmental law that promotes the enhancement of the environment and established the President's Council on Environmental Quality (CEQ). The law was enacted on January 1, 1970.Un ...
(NEPA), an Aquatic Resources Monitoring and Mitigation Plan (ARMMP) was required to be developed before the project could begin construction.endangered species
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...
on a temporary, emergency basis. The developer, Ormat Technologies
Ormat Technologies, Inc. is an international company based in Reno, Nevada, United States. Ormat supplies alternative and renewable geothermal energy technology. The company has built over 190 power plants and installed over 3,200 MW. As of J ...
, agreed in August to temporarily cease construction and later asked that the judge allow it to scale back its plans by 80%.[
]
References
External links
*
{{Taxonbar, from=Q56346399
Anaxyrus
Endemic fauna of Nevada
Amphibians of the United States
Amphibians described in 2017