TROPHYC EN

In the last few decades, the introduction of invasive alien species (IAS) has been acknowledged as a major environmental issue worldwide, following the accumulation of evidence of their impacts on biodiversity, ecosystems, economy and human health. There is an urgent need to identify and test standardized and broad-scale indicators of the ecological impact of IAS in order to implement effective strategies of control and mitigation. However, research focusing on IAS impacts is mostly performed at relatively small spatial scales and thus is inherently limited in generalizability. This is particularly manifest for marine bioinvaders, for which large knowledge gaps exist, with consequences in terms of underestimated risks and delayed or, even worse, ineffective management. For consumer IAS located at various trophic levels, recent meta-analytical investigations have indicated that native responses to invasion depend critically on the invader’s trophic strategy.

The TROPHYC proposal builds on these premises, and proposes an advancement of the understanding through a methodological approach based on crowdsourced data. Specifically, the general aim of TROPHYC is to use the current invasion of the Mediterranean Sea by the invasive Atlantic blue crab Callinectes sapidus as a model to study the geography of the trophic impact of a consumer IAS. Target research groups will be identified throughout the whole Mediterranean basin and invited to provide specimens of blue crabs from local established populations and available knowledge on blue crab invasion in the geographical area of competence. Stable isotope analysis will be carried out on collected samples to estimate the trophic position and isotopic niche metrics of the different populations, providing an assessment of the crab’s potential trophic impact of the blue crab by a conventional scientific knowledge (CSK) approach. At the same time, information on the species impact will be collated by using formal risk screening tools (AS-ISK) and local ecological knowledge (LEK) of target research groups. CSK and LEK data will be ultimately integrated in a Cumulative Impact Indicator within a spatially-explicit context. By means of a previously unattempted effort to collect and share standardized, broad-scale CSK and LEK information on an invasive species, TROPHYC will provide a valuable support to the management of C. sapidus in invaded Mediterranean waters, and will constitute a proof of concept that could be adapted to other invasive consumers at both a EU and global scale, ensuring replicability and a long-term scientific impact of the project.