Climate risk for Italian habitats

Abstract

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. While species-level effects of climate risk are widely investigated, habitat-level exposure to climate change has rarely been assessed. This reduces the comprehensiveness of habitat state assessment under the Habitats Directive, and risks creating a blind spot on Protected Area effectiveness. Here we quantified the future (year 2050) climatic exposure of 139 EUNIS level-3 habitats across Italy, using two complementary metrics: analog velocity and multivariate magnitude. We found that median analog velocity was generally modest (median =0.15; Std = 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; Std = 0.80) and 77% of habitat exceeded the critical threshold of 6.18. We also found a few habitats (2.15%) concurrently facing high velocity and high magnitude of climate change, mainly located in Apulia and Veneto. Mediterranean annual-rich dry grasslands and montane unvegetated inland shores were among the most exposed habitats (magnitudes {approx}7.1-7.3; velocities {approx}0.42-0.66 km/y), while cliff and mountain forest habitats in Sardinia and Sicily showed the lowest exposure. We urge countries to explicitly incorporate habitat-level exposure as part of national protection and restoration plans.