Climatic exposure of Italian habitats

Climate change is a major driver of global biodiversity loss and Europe is no exception, with several areas exposed to high climate velocity and/or magnitude. Within the rapidly warming Europe, Italy is facing particularly high risk as part of the Mediterranean region, with potentially dramatic consequences for its diverse habitat types. Habitat-level exposure to climate change has been assessed to a lesser extent compared with species exposure. The uncertainties about habitats' exposure reduce the comprehensiveness of habitat state assessment under the Habitats Directive, and risks creating a blind spot on protected area effectiveness in the long term. Here we quantified the future (year 2050) climatic exposure (i.e., extent of change in physical environment) of 139 EUNIS level-3 habitats across Italy, using two complementary metrics: analog velocity (i.e., the distance of regions that are projected to have similar future climatic conditions) and multivariate magnitude (i.e., the difference between future climatic conditions and the historical baseline). We found that under SSP3–7.0 median analog velocity was generally modest (median = 0.15 ± 0.41 km/y), and only a few habitats exceeded the critical velocity threshold of 0.5 km/yr. Instead, magnitude was typically high (median = 6.54 ± 0.80) and 77% of habitat exceeded the critical threshold of 6.18. Mediterranean annual-rich dry grasslands and Montane unvegetated inland shores were among the most exposed habitats. As many threatened habitats are increasingly exposed to climate-driven pressures, countries should urgently integrate climate exposure into national protection and restoration planning.