Species-specific functional traits rather than phylogenetic relatedness better predict future range-shift responses of odonates

Climate change has the potential to modify habitat characteristics and, consequently, induce species responses to ongoing environmental changes. Functional traits determine both if a species can persist and maintain stable population sizes in particular ecological conditions, and its capacity to disperse to more favourable habitats. Given that functional traits evolve over time, one could expect closely related species to show similar responses to climate change, which should identify vulnerable lineages. Alternatively, species-specific functional traits may anticipate species responses to climate change, and therefore, trait composition should be a strong predictor. We compiled a comprehensive dataset of functional traits of 84 Iberian and Moroccan odonates species and built a phylogenetic tree to determine if dissimilarity of traits and phylogenetic relatedness are relevant to better discriminate species range-shift responses to climate change. Modelling results for 66 species showed clear impacts of the increase in temperature and drought events on their potential distribution. The traits that best-discriminated species that expanded their ranges were multivoltinism, short-life cycles and preference for temporary habitats, whereas species with a reduced and displaced potential distribution were mostly semivoltine, with a short flying season, oviposition on gravel and restricted to permanent streams, small rivers or oligotrophic lakes. Trait conservatism was rejected and phylogenetic relatedness was a poor predictor of range shifts. Considering odonates as model organisms, traits such as voltinism, beginning and prolongation of flight period and preference of temporal habitats should be examined to anticipate range-shift responses of freshwater insects to climate change.