The cane toad (Rhinella marina) has become invasive in much of its introduced range, impacting significantly on biodiversity in these regions. Not only does the cane toad prey upon and compete with native species, it also produces a potent toxin that can be deadly to would-be predators. Nowhere is the impact of the cane toad more apparent than in Australia and a recent study indicates that edge-of-range populations there are evolving to become even better invaders.
A report, written by CABI for the Scottish government, Defra and the Welsh Assembly Government, estimates the cost of invasive non-native species to Great Britain in unprecedented detail. Invasive non-native species can have wide-ranging effects on biodiversity, crop production and people’s livelihoods. A better understanding of the negative impacts of invasive species will help to make people aware of invasive non-native species, to prevent new introductions and to deal with the problems caused by established invasive species.
Mikania micrantha (mile-a-minute weed or South American Climber) is a major invasive alien weed in many of the tropical moist forest regions of Asia. This neotropical vine is able to smother plants in agricultural ecosystems, agroforestry and native habitats. Conventional control methods of manual removal (slashing) or herbicide application, are expensive, ineffective, not sustainable, and can be environmentally damaging. Classical biological control was considered the best option to manage this weed, and CABI was funded by DIFID (UK- Department for International Development) to implement this strategy in India. The research culminated in the release of a coevolved, host specific, rust pathogen (Puccinia spegazzinii), from the South America native range of the weed, into Kerala and Assam. This rust pathogen infects all aerial parts of the plant (leaf, petiole and stem), leading to cankering and whole plant death (see image below).