Repelling the invader: turning the tide on Ascension’s Mexican thorn
Mexican thorn is the most damaging invasive species on Ascension Island. Introduced purposely, this weed has naturalised and spread rapidly, outcompeting native vegetation and negatively impacting wildlife, while encouraging other invasive rodents. This project will take a strategic and integrated approach to controlling thorn on Ascension including a rigorous assessment of further biocontrol and improved chemical and mechanical treatment. The project will ensure local capacity is built to deliver those most appropriate and cost-effective for Ascension. The outcome will be a step-change in our ability to control Mexican thorn and result in a long-term contraction of its range and restoration of habitats.
Saving Tristan’s only native tree and its associated unique buntings
Invasive non-native species are a major threat on oceanic islands due to their vulnerability and endemism, typical of island ecosystems. On Tristan da Cunha, a remote group of islands in the South Atlantic, Brown soft scale, (Coccus hesperidum), an invasive alien scale insect, has infested Tristan’s only native tree, Phylica arborea; and is now threatening the extinction of one of Britain’s rarest bird species, Nesospiza buntings. There is, therefore, an urgent need to find an appropriate method to mitigate the impact of the scale insects and prevent the total collapse of the Phylica forest. The aim of this project is to select and safely test suitable biocontrol agents to reduce scale numbers below a damaging threshold and safeguard Tristan’s endemic buntings.