One frog, one mountain


Alouise Lynch, Bionerds, and Dr Jeanne Tarrant, the EWT’s Threatened Amphibian Programme Manager,

Rough Moss Frog on rock

Rough Moss Frog (Arthroleptella rugosa). Photo credit: Johan du Plessis

The Rough Moss Frog (Arthroleptella rugosa) is a Critically Endangered frog species found only on a single mountain range, the Klein Swartberg, in the Overberg district of the Western Cape, South Africa. In 2020 we realized that this little frog was in big trouble. Its habitat was being degraded rapidly by alien invasive vegetation to such an extent that the survival of the only known population of this species was uncertain.

With this realization, the Endangered Wildlife Trust (EWT) approached the IUCN Save Our Species fund for support to implement a critical rapid action intervention to save this population. In 2021, the IUCN Save Our Species answered the plea for assistance with co-funding from the European Union. This support allowed us to develop a firebreak system around this original population of Rough Moss Frogs. This critical intervention supported the planning of an ecological burn in 2022 as a tool to manage an extensive pine infestation that was damaging the population’s seepage habitat. This was a novel approach to amphibian species conservation on the Klein Swartberg Mountain, not least globally.

During the surveys supported by the SOS project, an additional three populations of this species were recorded on the Klein Swartberg by project partner Bionerds PTY Ltd. This was a welcome discovery, bringing the known populations to four. Two of these newly discovered populations were in well-managed natural habitats, also good news for the species!

On 16 March 2022, the firebreaks and planning for the ecological fire were completed by our contractor, Enviro Wildfire, through the employment of an alien vegetation clearing team from the local community of Caledon. The planned ecological burn took place during the week of 28 March 2022. The ecological burn was intended to eradicate invasive pine trees and allow for the recovery of natural fynbos vegetation, not only for the conservation of the Rough Moss Frog population but also for various other Endangered plants and animals. This intervention will also benefit the local community living in the catchment zone below the Klein Swartberg by increasing the water yield from the mountain draining into the aquatic systems in the seeps and rivers and the agricultural community reliant on these water resources.

 Team preparing firebreaks in Swartberg

Team preparing firebreaks in the Klein Swartberg, Western Cape, South Africa. Photo credit: Johan du Plessis

The burn was successful, with very few invasive alien pine trees remaining. And those that survived will be cleared mechanically in the coming months, alongside the development of a long-term alien vegetation clearing plan covering the full extent of the mountain and supported by project partners, the Klein Swartberg Conservancy and the Fynbos Trust. In addition to the 800 ha planned for the burn, over  4,500 ha of the mountain also burnt, including the three additional Rough Moss Frog population sites discovered during the project. Post-fire monitoring by the team has happily confirmed the presence of Rough Moss Frogs at one of the burn sites. These populations will be continuously monitored over the coming breeding season (June onwards). This monitoring will include post-fire bioacoustics monitoring (recording of frog calls) to compare with pre-fire recordings to document the recovery of these populations in the coming years as habitat is restored.

Post burn in the Klein Swartberg Team preparing firebreaks in the Klein Swartberg, Western Cape, South Africa. Photo credit: Johan du Plessis

Southern slope after ecological burn in the Klein Swartberg, Western Cape, South Africa. Photo credit: Johan du Plessis

The project not only achieved its objective of significantly reducing the threat of invasive vegetation to the original population but also forged partnerships, discovered previously unknown populations of a Critically Endangered species and initiated formal habitat protection processes for five properties where the species is now known to occur.

This project is supported by IUCN Save Our Species and co-funded by the European Union. The contents of this publication are the sole responsibility of the Endangered Wildlife Trust and do not necessarily reflect the views of IUCN or the European Union.