A trait-based approach for assessing and mapping niche overlap between native and exotic species: the Mediterranean coastal fish fauna as a case study

• Published in: Diversity & distributions Vol. 20; no. 11; pp. 1333 - 1344
• Main Authors: Elleouet, J., Albouy, C., Ben Rais Lasram, F., Mouillot, D., Leprieur, F.
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Publishing Ltd 01-11-2014; John Wiley & Sons Ltd; Blackwell; John Wiley & Sons, Inc
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Applied ecology; Biodiversity; BIODIVERSITY RESEARCH; Biological and medical sciences; Biological invasions; coastal fishes; Conservation, protection and management of environment and wildlife; endemic species; exotic species; Fish; functional traits; Fundamental and applied biological sciences. Psychology; General aspects; Marine ecology; Mediterranean Sea; Native species; niche overlap; Nonnative species; Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; Sea water ecosystems; Synecology; Mediterranean Sea; Introduced species; Biological invasion; Endemic species; Fauna; Functional trait; niche overlap; Biological invasions; Overlap; Biodiversity; coastal fishes; Case study; Marine environment; Invasive species; exotic species; functional traits; Ecological niche; Mediterranean region; Environmental monitoring; Mediterranean Sea; Native species; Environmental protection
• ISSN: 1366-9516; 1472-4642
• DOI: 10.1111/ddi.12235

Aim We propose a trait-based approach for assessing and mapping potential niche overlap between native and exotic species at large spatial scales. Location The Mediterranean Sea. Methods We developed two complementary indices based on ecological, biological and ecomorphological similarities between native and exotic species. The first index (FNNr) allows identifying areas where native species are the most at risk in terms of potential ecological interactions with exotic species. The second index (FGO) is species-specific and allows identifying native species that display the broadest functional niche overlap and range overlap with exotic species. We illustrated our approach using the Mediterranean coastal fish fauna as a case study. Results We found that endemic and exotic fishes had a similar global functional niche at the Mediterranean scale, that is, they filled the same functional space defined by trait axes. FNNr hotspots were found to be moderately congruent with exotic species richness hotspots. Higher values of FNNr were observed along the coasts of the Levantine Sea. The computation of the FGO index showed that the geographical range of a given endemic species overlapped in average with 52 exotic species. Species showing the highest FGO values displayed localized and/or fragmented distributions in the eastern Mediterranean basin. Main conclusions Our findings suggest that the number of exotic species alone cannot be used as a broad-scale indicator of potential impact because this metric does not account for functional relatedness between native and exotic species. The trait-based indices developed in this study can be used for other taxa in both aquatic and terrestrial ecosystems and should help environmental managers to set up local-scale studies on areas where the potential impact of exotic species on native biodiversity is the highest.