Impacts of extreme climatic events on diurnal butterflies in Italy

Under present climate change conditions, the frequency and intensity of extreme events such as heatwaves, droughts, and heavy rainfall are progressively increasing with dramatic effects on biodiversity. Little is known, however, about the potential effects of these extreme events on species distribution, and, in particular, on diurnal butterflies which are important pollinators in natural ecosystems, contributing significantly to agricultural productivity. Worryingly, a growing body of literature suggests that climate change may result in the extinction and decline of many butterfly species. Understanding which species and areas are most vulnerable to climate change is essential for planning conservation and mitigation efforts.

In this work we present the results of an analysis of the possible impacts of climate extremes on the distribution of diurnal butterflies in Italy, a study area characterized by three biomes with complex topography, climate, and abundance of locally adapted species. We created a new dataset of biodiversity-oriented indexes of extremes related to temperature and precipitation, and we sourced species distribution data from online databases. Then we analyzed, for a reference period (1971-2000) and for 2 future scenarios for the period 2041-2070, the climate suitability for the species. 

Results show, under both scenarios, a general loss of climate suitability which affects, in particular, specialist and mountain species, whereas lowland and generalist species remained more stable.

Given the projected severe impacts of extreme climate events on butterflies, proactive measures tailored to each biome and focused on the most vulnerable species are necessary. These efforts should be complemented by adaptive management strategies to facilitate species responses to shifting climate suitability. The work has been supported by LIFE21-CCA-IT-LIFE BEEadapt/101074591 a project co-financed by the European Commission through the LIFE Programme, within the sub-programme dedicated to climate adaptation actions.