Toad in geothermal power fight gets endangered status

A Dixie Valley toad near the site of a power plant site in Nevada. [AP photo]

A tiny Nevada toad at the centre of a legal battle over a geothermal power project has officially been declared an endangered species, after US wildlife officials temporarily listed it on a rarely used emergency basis.

"This ruling makes final the listing of the Dixie Valley toad, " the US Fish and Wildlife Service said in a formal rule published on Friday in the Federal Register.

The spectacled, quarter-sized amphibian "is currently at risk of extinction throughout its range primarily due to the approval and commencement of geothermal development," the service said.

Other threats to the toad include groundwater pumping, agriculture, climate change, disease and predation from bullfrogs.

The temporary listing in April marked only the second time in 20 years the agency had taken such emergency action.

Environmentalists who first petitioned for the listing in 2017 filed a lawsuit in January to block the construction of the geothermal power plant on the edge of the wetlands where the toad lives about 160 kilometres east of Reno - the only place it's known to exist on earth. "We're pleased that the Biden administration is taking this essential step to prevent the extinction of an irreplaceable piece of Nevada's special biodiversity," said Patrick Donnelly, Great Basin regional director for the Centre for Biological Diversity.

The centre and a tribe fighting the project say pumping hot water from beneath the earth's surface to generate carbon-free power would adversely affect levels and temperatures of surface water critical to the toad's survival and sacred to the Fallon Paiute-Shoshone Tribe.

The Fish and Wildlife Service cited those concerns in the final listing rule.

"The best available information indicates that a complete reduction in spring flow and significant reduction of water temperature are plausible outcomes of the geothermal project, and these conditions could result in the species no longer persisting," the agency said.

"Because the species occurs in only one spring system and has not experienced habitat changes of the magnitude or pace projected, it may have low potential to adapt to a fast-changing environment," it said. "We find that threatened species status is not appropriate because the threat of extinction is imminent."