Endangered western leopard toad threatened by an invasive look-alike, public urged to help.
Cape Town – The discovery of the invasive guttural toad species on a property near Seascape Road in Noordhoek has set off alarm bells in conservation circles, who fear the invader species might hinder the livelihood of the endangered western leopard toad that is endemic to the area.
Noordhoek is one of the most important traditional breeding areas of the endemic and endangered western leopard toad (Sclerophrys pantherinus), a close relative of the more common guttural toad (Sclerophrys gutturalis).
Guttural toads and leopard toads look very similar to the untrained eye, and the identification of eggs and tadpoles (which look almost identical even to professionals) is particularly difficult.
But the City of Cape Town and are urging residents to be on the lookout for the guttural toad nonetheless, in a bit to save the natural habitat and breeding grounds of its more endangered relative.
The main differences between the two species are:
The City’s service provider, NCC Environmental Services, who currently run the guttural control programme in Constantia, will now also focus on the Noordhoek area.
NCC will also work closely with Toad Nuts, a local group formed to protect and save the western leopard toad.
Residents are urged to listen for the distinctive guttural toad call and to report the occurrence immediately by sending an e-mail to gutturaltoad@ncc-group.co.za
The City also asks residents never to move any toad, tadpole or eggs between water bodies.
Johan van der Merwe for the environmental affairs of the City of Cape Town says the western leopard toad and guttural toad do not co-exist naturally and “this situation may cause several complications. These may include competition for food, predation, and the introduction of external diseases and pathogens. Hybridisation could also be a potential threat.
“Following this early detection of the guttural toads in Noordhoek, there must be a rapid response by conservation authorities, the Invasive Species Unit and residents. If all the individuals, tadpoles and eggs can be found during this early stage of the invasion, guttural toads can be removed from Noordhoek completely.
“The survival of the endemic western leopard toad depends on access to uninvaded breeding grounds such as Noordhoek. The advance of the guttural toad must, therefore, be stopped before guttural toads become established and form a viable breeding population in Noordhoek,” Van der Merwe says.
It is not just the frogs themselves that can create problems, but the diseases and parasites that accompany the frogs may cause further environmental harm.
Once the invasion of guttural toads into Noordhoek is past the early detection and rapid response stage, control becomes extremely challenging and expensive.
This has already happened in Constantia, where an intensive five-year-old control programme has been unable to stop the spread of guttural toads into Bishopscourt. The City’s service provider, NCC Environmental Services, continues to fight the toad in the area.
Although the guttural toad is indigenous to South Africa, it does not naturally occur in the Western Cape.
Invasive species such as the guttural toad are introduced to areas outside their natural range either deliberately or accidentally. The likely scenario for an accidental introduction is that nursery plants were moved from the area where guttural toads naturally occur to Cape Town. Once they arrived at their new habitat, they reproduced and established the colonies that are now invading many water bodies in Constantia and Bishopscourt.
It could also be the case that well-meaning residents who do not want to harm animals but also don’t want them in their gardens, physically relocate toads to natural areas around the city. This is a highly problematic practice and causes havoc for nature conservation officials.
The most effective method of managing invasive species is to prevent them from being introduced to areas outside their natural distribution range in the first place.
This article has been adapted from traveler24.com, – Louzel Lombard
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