Gone to the frogs: tiny amphibians make for big find

University of Stellenbosch student Oliver Angus has made a rare and unexpected discovery of a critically endangered micro-frog species in the Western Cape.

This discovery at the Nuwejaars wetlands appears to show a previously unknown subpopulation, making it only the fifth left in the world.

“It also seems to indicate that the Agulhas Plain is a stronghold for the species, with another subpopulation found in the neighbouring Agulhas National Park.

“The army of frogs was found by Oliver Angus, working with the conservation team at the Nuwejaars Wetlands Special Management Area. While they managed to catch five individuals for identification, they heard about 30 individuals calling,” said Ross Kettles, Nuwejaars Wetlands area project manager.

Oliver was working with the World Wide Fund for Nature (WWF).

“This find was completely unexpected. We were actually searching for Cape Platanna when we found the micro frog. This is an awesome find for the species: this is a whole new catchment for them, and it’s a 20km range extension.”

“They are almost wiped out; it’s awesome to have a nice big population,” said Oliver.

Kettles said they were optimistic that the population would grow and survive, though they had no idea what the timeline might be. “They might be tiny, but they are important indicators of the health of the environment and provide food for other animals in the food chain.”

According to the Kenilworth Racecourse Conservation Area (KRCA), this tiny frog is one of the smallest amphibians in SA, with an adult length of about 15mm.

“It only occurs in certain areas between Betty’s Bay and Cape Agulhas and on one site on the Cape Flats, where it survives in acidic blackwater fynbos vleis. The filling in, drainage or pollution of vleis, and alien vegetation encroachment, are major threats facing this frog species. 

“Although more than 80% of its habitat has been destroyed through development and associated threats, at least 70% of this disappeared more than 30 years ago,” said KRCA.

The KRCA’s micro frog population is the only one still in existence on the Cape Flats, and a careful monitoring system is critical to ensure long-term survival.