Climate change and its impact on epigean and hypogean carabid beetles

Background and purpose: The approaches to the impact of climatechange on carabid beetles are highly differentiated. We review here moststudies that tried to compare past situations with present time conditionsthat may concern ground beetle species, populations and phenology, areaand upslope shifts. Both epigean and hypogean domains have taken in considerationand, whenever possible, all time scales addressed by the authors.Materials and methods: The methods adopted vary in relation to thetime scale. Geo-period studies cover the largest time lapse, and comparePlio-Pleistocene fossil species assemblages with present ones. Further approachesconcern long-term observations based on museum materials andthe response of carabids to climate or man-conditioned habitat changes.Primarily devoted to the understanding of climate change impacts on communitiesare the space-for-time and the time-per-time approach, that implythe comparison of year samples collected in the same site after some decades.Other long-term studies are devoted to the phenology changes. The impacton cave dwelling carabids has studied by recording the new taxa discoveriesduring the last two centuries.Results: Geo-period studies reveal strong area expansions restrictions orlocal extinctions of presently living ground beetles. The old idea of a stabilityof taxonomic status of such beetles seems to give way to a more dynamic visionof speciation events during the Quaternary, as suggested by recent populationgenetics studies on Trechines and some Carabus species. Long term studiesbased on museum materials reveal population and area declines of large andbrachypterous species of open lands, but the climate responses are difficult todisentangle from anthropogenous habitat and landscape modifications. Thespace-for-time approach focuses especially glacier forelands but seems promisingalso in forecasting species declines starting from climate gradients in forests.The time-for-time (time lapse) monitoring of ground beetle assemblages hasadopted so far in Mediterranean mountains and Dolomites. It reveals thatin the last three decades a strong uphill shift has observed especially in openland assemblages. In the Dolomites local extinctions and decline of species’diversity has recorded around or above the tree line. The long-term monitoringof carabids in defined habitats provides extremely rich databases that canbe useful in explain the relationships between climate change, populationdecline or increase and species phenology. Hypogean obligate troglobitic carabidsrevealed to be extremely sensitive to global warming, as testified by thecontinuous appearance of new highly evolved taxa that concentrate in theperiods of fastest temperature rise of the last century. Conclusions: Epigean and hypogean carabid beetles are excellent and„multitask” indicators of climate change. Moreover, their response time toclimate changes seems to be shorter than for plants.