Through time and color: NDVI as a diagnostic tool of the historical dynamics of pollinating hoverfly communities

The impacts of climate change on the Castiglione dei Pepoli Abies forest, a peculiar ecological habitat in Tuscan-Emilian Apennines, has been evaluated in order to study potential changing in habitat equilibrium and loss of biodiversity. Since the 1950s, international expeditions have uncovered similarities in meteorological conditions between this forest and weather stations in North Europe. Entomological surveys evaluated biodiversity of hoverflies (Diptera Syrphidae) and other taxa since the sixties. The present study delves into the evolution of hoverfly communities over six decades, correlating diversity trends with meteorological conditions. Temperature and precipitation patterns, alongside vegetation changes, have been scrutinized. The Normalized Difference Vegetation Index (NDVI) highlights shades of color that indicate changes in environmental health and vegetation cover and has been employed in this study to track potential vegetation changes over time and explore their impact on the dynamics of hoverfly communities, particularly focusing on genera with phytophagous larvae, which are more sensitive to vegetation alterations. Initial findings suggest declines of species richness in some phytophagous genera, and a parallel increase of other genera, indicating shifts in habitat suitability. While meteorological records indicate a significant temperature increase, precipitation analyses did not reveal a significant trend. This research enhances our understanding of community dynamics of an important bioindicator taxon like hoverfly, guiding the development of conservation strategies and techniques.