Life history traits and distribution patterns of native and alien Iberian fish

Carlos Cano-Barbacil, Johannes Radinger and Emili García-Berthou, Institute of Aquatic Ecology, Universitat de Girona, Girona, Spain, Johannes Radinger, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany

Background/Question/Methods
Trait-based approaches are commonly used in ecology to understand the environmental filtering or the biotic responses to anthropogenic perturbations. Specifically, fish trait information is especially difficult to obtain and some species present scarce coverage and data availability in trait databases. Therefore, we investigated the reliability of 27 traits and generated an open, up-to-date and comprehensive consensus trait database of Iberian inland fish. We then used this information to understand the relationship between most important distributional drivers and fish traits. Thus, we modelled distributions of the 68 most common native and alien inland fish species across the Iberian Peninsula using the BIOMOD computational framework. Finally, to explore the importance of specific environmental variables in determining the distribution of different traits of freshwater fish, we used a redundancy analysis (RDA).
Results/Conclusions
Our results showed that topographic and climatic variables were generally more important than anthropogenic factors in explaining fish distributions. We found significant differences in the importance of variables explaining the distribution of native vs. alien species, e.g. mean temperature and damming had positive effects on the distribution of alien species but were less important for native fishes. Moreover, species whose distributions were highly sensitive to ‘annual mean temperature’, ‘stream order’, ‘average precipitation seasonality’ and ‘upstream reservoir capacity’ were characterized by inhabiting the water column, being phytophilic spawners and larger-bodied, and many of these species were alien species. By contrast, native species, whose distributions were particularly constrained by river basins, were more rheophilic. To sum up, native and alien species showed marked differences in their traits and in the importance of factors explaining their distribution. We also emphasize the importance of considering the precision and standardized measurement of fish traits for the improvement of future trait-based approaches.