Influence of extreme climatic effects on butterfly assemblages in a Mediterranean landscape, with new records of threatened and endemic species

Climate change is seriously threatening biodiversity and, especially, insects because their biological cycles are highly dependent on environmental conditions. We studied (1) how climate characterised by droughts and heatwaves affected the butterfly assemblage at four sampled sites in Campo de Montiel (central Spain) over three consecutive years; and (2) the differences in the assemblage abundance, species richness, density, and diversity among sites that represent a variety of land use/cover types. Sites were sampled with transects using the Butterfly Monitoring Scheme methodology (Pollard & Yates, 1993). A total of 8,275 butterflies and 69 species were sampled across sites and years. Sites were well sampled in the three years according to species richness estimators and accumulation curves. The relationship between the mean length of dry spells and butterfly abundance was negative and significant at all sites. However, heatwaves did not affect butterfly abundance and species richness. There were no significant differences in the ecological parameters studied among sites. Mediterranean forest transects tended to have higher values of ecological parameters than those dominated by more degraded vegetation, pine plantations and cropland intensification. Butterfly assemblage and diversity were positively related to the presence of semi-natural habitat with traditional agricultural and livestock uses. Our surveys recorded Polyommatus celina for the first time in Castilla-La Mancha. Two endangered and endemic species, Polyommatus violetae and Kretania hesperica, were recorded at the site with higher Mediterranean forest cover, which increases the conservation value of this site. Maintaining semi-natural habitats and traditional farming systems may allow butterfly assemblages to be more resilient to climate change.