The Otago Regional Council regional threat assessment said long-tailed bat numbers were expected to decline significantly — a greater than 70% decline over the next three generations.
The just-published regional threat assessment listed long-tailed bats as "regionally critical", the most severely threatened status, indicating the species faced "an immediate high risk of extinction in Otago".
The Southern lesser short-tailed bat, on the other hand, while less endangered nationally, were listed as "data deficient" as the sub-species had not been observed in the region recently.
The highly mobile mammals had been seen within 2km from Otago’s border with Southland, the report said.
Council terrestrial ecologist Scott Jarvie, along with a panel of experts, completed the threat classification study.
It is the council’s second threat assessment after its first, published in April, found most of the region’s 34 species of reptile were threatened with extinction.
Mr Jarvie is due to present his findings to the council’s environmental science and policy committee in Wanaka today.
His report said regional councils had statutory obligations to maintain indigenous biodiversity under the Resource Management Act.
"Knowledge of the threatened species present at a site is of particular importance for both RMA consenting processes and conservation planning such as that associated with pest control programmes for biodiversity restoration purposes.
"Although the Catlins in south-eastern Otago and the Dart in western Otago have been identified by [the Department of Conservation] as priority sites for management of long-tailed bats, all bat populations should be conserved due to severe threats facing the species," the report said.
The long-tailed bat, it said, had been observed widely across Otago but was severely threatened, by introduced predators, habitat loss, and human-induced climate change.
Among the threats noted in the report, wind farms were highlighted.
Collisions with towers and turbine blades and injuries to animals caused by a "decrease in air pressure in the proximity of rotating turbine blades" were both possible. Long-tailed bats had been recorded in, or within a night’s flying range of three districts in the region: Central Otago, Clutha and the Queenstown Lakes district.
Southern lesser short-tailed bats, observed at Eglinton Valley, were within a night’s flight of Queenstown Lakes.
Greater short-tailed bats, last seen on Big South Cape Island in the southern Muttonbird Islands, in 1967, were listed as regionally extinct.
