Using ecophysiological traits to predict climatic and activity niches: lethal temperature and water loss in Mediterranean ants

Abstract

AbstractAimUnravelling the constraints acting on the distribution and abundance of species is a major goal in ecology. Climatic niche models have become an important but controversial tool for predicting the consequences of global warming for species distributions. However, to date, classical ecophysiological traits such as thermal tolerance and water loss have rarely been accounted for in species distribution models. Here we meet the challenge of linking ecophysiological measures with climatic niche descriptions at two different spatial scales across ant species in a comparative modelling framework.LocationWestern Europe.MethodsTwo ecophysiological traits (lethal temperature and water loss) were characterized for 17 sympatric Mediterranean ant species under controlled laboratory conditions. These data, along with two eco‐behavioural traits (timing of activity and habitat specialization) were then used in models examining the species climatic and activity niches, i.e. at the biogeographical and local scales. Climatic niches were built using species distribution maps, while activity niches were built using activity data gathered in the field.ResultsPhysiological traits characterized in the laboratory (particularly lethal temperatures) explained 50% of the interspecific variation in climatic envelopes, especially the maximum temperatures experienced by species in their geographical ranges. Habitat specialization also made an important contribution; other traits such as water loss did not appear to be important. Physiological lethal temperatures also helped define activity niches at the local scale, especially in the case of behaviourally dominant species.Main conclusionsRelatively simple physiological traits alone, especially thermal tolerance, combined with some behavioural and natural history traits, can be important predictors of species biogeographical climatic niches. Thermal constraints and behaviour may thus be promising directions for studies seeking to predict species distributions in the face of climatic change.