Using a habitat model to assess the risk of invasion by an exotic plant

Invasion by exotic species is one of the main threats to the conservation of biodiversity. Once an invasive species becomes firmly established. its control can often be difficult and eradication is usually impossible. In addition, the impact on natural communities and ecosystem processes can be very serious. Thus, it is important to develop prospective work that allows the detection of invasions in their initial stages. A fundamental component of this strategy consists of identifying those environments that are more prone to be colonised, in order to optimise monitoring and early control actions. In this work we develop a habitat model to evaluate quantitatively the risk of invasion by exotic species. We measured the probability of establishment of an Australian halophytic shrub, the old man saltbush, Atriplex nummularia Lindl., in different coastal habitats of the Islas de la Ria de Bahia Blanca Nature Reserve (Buenos Aires, Argentina) as a case study. We conclude that these kind of models can aid exotic species management. (C) 2000 Elsevier Science Ltd. All rights reserved.