Climate warming threatens critically endangered wingless stonefly Riekoperla darlingtoni (Illies, 1968) (Plecoptera: Gripopterygidae)

The critically endangered wingless stonefly, Riekoperla darlingtoni (Illies, 1968), is endemic to the summit of Mt Donna Buang, Victoria, Australia. The known distribution of this species is within three short sections of alpine springs, making this species particularly vulnerable to climate change. We assessed changes in population abundance at the presumed type locality from 2005 to 2019. We found that the abundance of nymphs had decreased by more than 80% following the very dry winter of 2006 without a noticeable recovery. We also used environmental DNA (eDNA) to search for more localities within the species suitable habitat to re-evaluate its distribution. The eDNA survey uncovered two new localities 2.5 km west of the previously known populations, increasing the extent of occurrence to 0.37 km(2) for a total of five localities. The species requires urgent listing under national environmental conservation legislation in Australia, an associated action plan and further surveys using eDNA to identify more locations. The eDNA approach allows reliable detection of this elusive species over a range of up to 200 m. Climate warming and drying resulting in the reduction in snowfall, as well as increasing human traffic and associated infrastructure at the mountain summit, are the main processes thought to be key threats to this unique and susceptible species. Implications for insect conservation These surveys provide the data for listing of the species under the Australian federal Environment Protection and Biodiversity Conservation Act (EPBC) 1999. The newly developed eDNA methods allow for efficient and effective surveying of R. darlingtoni in order to obtain a more complete understanding of its distribution for future conservation planning.

Automated summary

The critically endangered wingless stonefly, endemic to Mt Donna Buang in Victoria, Australia, has shown a drastic decline in population abundance without recovery following a dry winter. Environmental DNA surveys revealed two new localities, expanding the known distribution of the species.