Alien species: to remove or not to remove? That is the question

Invasive alien species (IAS) are universally known for being a controversial management issue. What makes IAS management a particularly thorny question is that although numerous studies document the negative effects of IAS, the potential benefits of IAS are generally underreported. This may result in wrong assessments on the real socio-economic and environmental impact of IAS. This study aimed to provide new insights to support the decision making of IAS management. In particular, the biased approach to IAS management seems to be a likely consequence of the lack of appropriate metrics able to assess the real IAS impact. A basic aspect of IAS management is to decide whether and when IAS removal is a suitable action. Specifically, this study supported the idea that IAS removal may be considered as a possible solution only after establishing a tipping point relying on economic, cultural and pragmatic evaluations. This analysis should include the identification of the ecosystem services damaged and provided by IAS, the attribution of an economic value to such ecosystem services, and when expressing the interaction between IAS and culture is not possible in monetary terms, then social values and cultural traditions should be incorporated in any management plan. Novel ecosystems are now a fact worldwide that should prompt to be realistic about the extent of efforts required for IAS removal. A significant step towards well-pondered decisions should consider that a change in host communities does not imply necessarily harm, and that the functional roles of a species matter more than its origins.