Dixie Valley toad

The Dixie Valley toad (Anaxyrus williamsi or Bufo williamsi) is a species of toad in the family Bufonidae. It is endemic to Churchill County in the state of Nevada in the United States.[5] It was the first new toad species to be described from the United States since the description of the now-extinct in the wild Wyoming toad (A. baxteri) about 49 years prior.[5][6][7]

Dixie Valley toad
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Anura
Family: Bufonidae
Genus: Anaxyrus
Species:
A. williamsi
Binomial name
Anaxyrus williamsi
(Gordon, Simandle, & Tracy, 2017)
Synonyms[4]

Bufo williamsi Gordon, Simandle & Tracy, 2017

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 in the Pleistocene until the receding water isolated the different populations, leading to speciation.[6]

Distribution and habitat

The Dixie Valley toad is found only in a small complex of vegetated spring-fed marshlands in Dixie Valley, 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.[6]

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.[6]

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[8] geothermal power plant, alleging that operations may degrade the marshland that it lives in by drying up the springs.[6][9][10]

As part of an environmental review performed by the Bureau of Land Management (BLM) prior to permitting approval, required by the National Environmental Policy Act (NEPA), an Aquatic Resources Monitoring and Mitigation Plan (ARMMP) was required to be developed before the project could begin construction.[8] The purpose of the monitoring and mitigation plan is to ensure that significant adverse effects on aquatic resources (water resources, riparian and wetland vegetation, and aquatic special status species) do not occur. The ARMMP[11] was developed in close coordination between the developer and the BLM prior to the BLM's finding of no significant impact in 2021.[12]

In April 2022, the Fish and Wildlife Service designated the Dixie Valley toad an endangered species on a temporary, emergency basis.[13][14] The developer, Ormat Technologies, agreed in August to temporarily cease construction and later asked that the judge allow it to scale back its plans by 80%.[15] A permanent decision to list the species as endangered was published and took effect on December 2, 2022.[3]

References
  1. IUCN SSC Amphibian Specialist Group (2022). "Anaxyrus williamsi". IUCN Red List of Threatened Species. 2022: e.T181492000A181937150. Retrieved 24 December 2022.
  2. "Dixie Valley Toad (Anaxyrus williamsi)". Environmental Conservation Online System. U.S. Fish & Wildlife Service. Retrieved 3 June 2023.
  3. 87 FR 73971
  4. "Anaxyrus williamsi (Gordon, Simandle and Tracy, 2017)". Integrated Taxonomic Information System. Retrieved 3 June 2023.
  5. "AmphibiaWeb - Anaxyrus williamsi". amphibiaweb.org. Retrieved 2019-03-17.
  6. Tracy, C. Richard; Simandle, Eric T.; Gordon, Michelle R. (2017-07-06). "A diamond in the rough desert shrublands of the Great Basin in the Western United States: A new cryptic toad species (Amphibia: Bufonidae: Bufo ( Anaxyrus )) discovered in Northern Nevada". Zootaxa. 4290 (1): 123–139. doi:10.11646/zootaxa.4290.1.7. ISSN 1175-5334.
  7. "Rare discovery of three new toad species in Nevada's Great Basin". phys.org. Retrieved 2019-03-17.
  8. EPlanning, BLM (2017-05-01). "Environmental Assessment, ORNI 32 LLC, Dixie Meadows Geothermal Utilization Project" (PDF). eplanning.blm.gov. Retrieved 2021-12-30.
  9. Grega, Kelcie (2019-12-02). "Imperiled Nevada toad's habitat threatened, environmentalists say - Las Vegas Sun Newspaper". lasvegassun.com. Retrieved 2021-12-16.
  10. GeoEnergy, Think (2021-11-24). "BLM Nevada approves geothermal power plant in Dixie Meadows". Retrieved 2021-12-16.
  11. EPlanning, BLM (2020-01-01). "Dixie Meadows Geothermal Project, Aquatic Resources Monitoring and Mitigation Plan, Dixie Valley, Nevada" (PDF). eplanning.blm.gov. Retrieved 2021-12-30.
  12. EPlanning, BLM (2021-11-23). "Finding of No Significant Impact, Dixie Meadows Geothermal Utilization Project" (PDF). eplanning.blm.gov. Retrieved 2021-12-30.
  13. Sonner, Scott (19 October 2022). "Rare toad fight similar to landmark endangered species case". AP News.
  14. 87 FR 20336
  15. Sonner, Scott (November 3, 2022). "New, unusual court bid in fight over endangered Nevada toad". AP News.
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