Microclimate data reveal microrefugia potential in European forests

Microrefugia are critical for preserving species under climate change as they could locally offer suitable climate conditions, allowing species to survive despite broader regional temperature increases. These areas may act as natural buffers, maintaining biodiversity and ecosystem functions by providing suitable habitats for species unable to migrate or adapt quickly enough to the changing climate. This study leverages fine-scale microclimate temperature data from the ForestClim database to identify potential microrefugia in European forests. We synthesize multiple climate characteristics of microrefugia (i.e. microclimate temperature offset, warming magnitude and forward and backward climate change velocity), into a microrefugia multifunctionality (MF) index that can be used to prioritize forest conservation. Our findings reveal notable geographical patterns in microrefugia potential, with higher MF indices in mountainous and coastal regions due to their unique topographic and climatic features. Tree cover density significantly influences MF, with dense canopies providing better thermal insulation. The study also underscores the importance of slope and elevation in enhancing microrefugia potential. Seasonal dynamics are evident in the microclimate offset, with different regions exhibiting varying buffering capacities throughout the year. The discrepancy between forward and backward climate change velocities highlights regions vulnerable to climate shifts and those likely to experience novel climate conditions. Our results emphasize the need for a multidimensional perspective on microrefugia in forests. The microrefugia multifunctionality index can be used to prioritize conservation efforts thereby mitigating the impacts of global climate change.