Mitigation and adaptation strategies for the control of biological invasions

Biological invasions are recognised to be a problem of growing severity. Human pathogens, weeds or pests in terrestrial systems and dominant alien species in freshwater or marine aquatic systems all impose significant costs in terms of forgone output or costs of control in every major system. Like many of the other environmental consequences of globalisation, biological invasions require that decisions be taken under uncertainty. Decision-makers in such circumstances have to choose between two main strategies: mitigation and adaptation. This paper characterises invasive species problems in terms of the properties of the stochastic processes they induce. It considers how mitigation and adaptation strategies may be modelled, and identifies the conditions in which each approach may be efficient and effective.