Climate warming effects on epiphytes in spruce forests of the Alps

Climate warming in the Alps is setting major challenges to biodiversity conservation, potentially threatening epiphytic bryophytes and lichens, whose poikilohydric nature makes their eco-physiology strongly dependent on ambient temperature. In this work, we used species occurrence data along steep elevational-temperature gradients within the range of Alpine spruce-dominated forests for modelling the response of epiphytes to temperature shifts. Results provide evidence for species-specific and differently shaped species-temperature relationships, indicating that the sensitiveness of single species to climate warming is likely to influence community composition. Many epiphytes that currently occur in Alpine forests are vulnerable to warming, and may soon experience local extinction. The local assessment of the current altitudinal range of species may provide a tool to monitor the effects of warming by identifying the most critical species and the locations where their conservation is expected to be more effective.