September 19th, 2024
Five years after the previous assessment, New Zealand's native long-tailed and lesser short-tailed bats continue to face threats to their survival, according to a report by the Department of Conservation (DOC). However, effective predator control in specific locations is helping to stabilise or even increase bat populations.
Dr Colin O'Donnell, DOC Principal Scientist and lead author of the report, was quoted in a DOC media release on Thursday that the overall situation for the country's only land mammals remains concerning, but there is progress in areas such as the Eglinton valley in Fiordland and Pureora, Whirinaki, and Rangataua forests in central North Island. In these locations, predator control measures have led to an increase in bat populations, with long-tailed bats growing by 4% annually in the Eglinton valley, and short-tailed bats by 8%.
However, in regions without predator control, bat populations are estimated to be declining at an annual rate of 5-9%. The primary threats to these native species are introduced predators, clearance of lowland forests, and loss of large old trees where bats roost. Additionally, the report highlights increased threats since 2017 from infrastructure projects, such as rural subdivisions, roads, and wind farms in bat habitats, and the emerging threat of climate change.
Despite these challenges, public interest in native bats and efforts from councils, iwi, and community groups to monitor and protect local bat populations have been on the rise. The DOC's national predator control programme prioritises the protection of the most at-risk native species and forests on public conservation land throughout New Zealand, using aerially applied 1080, toxins such as pindone in bait stations, and trapping to protect bats at various sites.
New Zealand is home to three subspecies of lesser short-tailed bats and the long-tailed bat, which has the highest threat ranking ('Threatened-Nationally Critical'). The country's Threat Classification System requires the DOC to review the status of all major native plant and animal groups every five years, with the involvement of species experts.