BLACK LIST AND ALERT LIST OF THE AQUATIC INVASIVE ALIEN SPECIES OF THE IBERIAN PENINSULA – Horizon scanning exercise focused on the high-risk aquatic invasive alien species for the Iberian inland waters.

Abstract

An important goal of LIFE INVASAQUA is to develop tools that will improve management and increase the efficiency of the Early Warning and Rapid Response (EWRR) framework for Invasive Alien Species (IAS) in the Iberian Peninsula. Horizon scanning for high risk IAS is basic when implementing measures to reduce new invasions and to focus efforts on the species already recorded. We developed a transnational horizon scanning exercise focused on inland waters of Spain and Portugal in order to provide a black list of current established aquatic IAS and an alert list of potential aquatic IAS that may pose a threat to aquatic ecosystems and socio-economic sectors in the future. We followed a structured 5-steps approach for horizon scanning that combined existing evidence about IAS with an expert scoring of prioritized taxa. A total of 126 IAS were prioritised in the final black list, representing the 41.2% of alien taxa recorded in Iberian inland waters. The top 24 species had a very high risk of impact because they obtained the maximum values in the risk-assessment scoring process. Moreover, the alert list included 89 IAS with a relevant risk of invasion in the Iberian Peninsula in the future, resulting in 11 taxa on the top with a very high risk of invasion.