Invasive toads are on the march across the southern suburbs of Cape Town. The City of Cape Town sounded the alarm yesterday over the discovery of guttural toads in Noordhoek, an important breeding area of the endangered western leopard toad. The guttural toads have spread rapidly in Constantia and Bishopscourt. Mayoral committee member for the environment, Johan van der Merwe, said the arrival of the guttural toad in Noordhoek could cause difficulties for western leopard toads."These may include competition for food, predation, and the introduction of external diseases and pathogens. Hybridisation could also be a potential threat," he said.The city council invasive species unit would try to remove guttural toads from Noordhoek, as well as their tadpoles and eggs. ..