To ban or not to ban, is it the only option to regulate biological invasions?

Abstract

Biological invasions are one of the major causes of biodiversity loss. To mitigate the impacts of invasive alien species (IAS) that pose a serious threat, the Spanish Catalogue of Invasive Alien Species was created; this was a dynamic tool in its creation but rigid in its application. Although it is subject to continuous modifications, the inclusion of an IAS in the Catalogue generally entails a generic ban on its possession, transport, traffic and trade. However, such rigidity often generates social conflict when IAS are economically exploitable resources. In this review, we exemplify the difficulties of implementing generic bans and propose that, to be effective, IAS regulation should expand the range of available tools (i.e. be flexible), beyond the dilemma of banning or not banning everything. To this end, we propose the creation of categories of IAS involving different levels of restriction and management strategies. In the case of widely distributed species with no technical possibilities for large-scale population control or prevention of their expansion, we bring up the permissibility of their commercial exploitation under certain restrictions, and point out the difficulties associated with banning such exploitation where it is already taking place. While simple solutions (i.e. to ban or not to ban) may be easier to understand and implement, they are not always the most effective. We therefore encourage the introduction of flexibility in legislation, which, while introducing greater complexity, it would facilitate the decision-making in the management of IAS, improve resource efficiency and reduce social conflicts associated with such management.