Page 44 - State of Biodiversity 2019-2020

40 STATE OF BIODIVERSITY REPORT 2019/2020
RESEARCHING TOADS AT THE BOTANICAL GARDENS
Human-mediated movement of species beyond their native range and the subsequent formation of invasive populations have become one of the hallmarks of the Anthropocene epoch.The establishment and propagation of invasive species is of great scientific interest as they can significantly impact ecosystems and imperil native species, but also because they represent real-world evolutionary experiments where keen theoretical insights can be gleaned. Some of the best illustrations of invasion-derived evolution in vertebrates have come from amphibians, notably the spread of toads. For example, changes in both morphology, physiology and behaviour of Cane Toads (Rhinella marina) has been observed across their invasive range in Australia and the islands of Hawaii, as well as when these invasive populations are compared to those from the species’ native range.
Members of the DSI-NRF Centre of Excellence for Invasion Biology (CIB) – Prof. John Measey, Dr James Baxter-Gilbert, Sam Peta and Max Mühlenhaupt – have been examining an African example of an invasive toad, the Guttural Toad (Sclerophrys gutturalis), to test if similar traits have promoted their invasion success. Guttural toads are native to eastern South Africa, but have established invasive populations in Cape Town, as well as the islands of Mauritius and Réunion. Interestingly, genetic research has determined that all invasive populations of the Guttural Toad originated from the same
Max Mühlenhaupt sampling collecting Guttural Toads for body measurements.