Area of habitat maps for Italian bumblebees

Area of habitat (AOH) maps show the distribution of the habitat available to the species within their geographic range and altitude limits. Information on the distribution of species’ habitats can be implemented to investigate biogeographical patterns, as well as to identify potential Key Biodiversity Areas. We produced high resolution global area of habitat maps for 28 species and subspecies of bumblebees occurring in Italy. The maps can be used as a reference for conservation planning and can help monitoring habitat loss.
Methods
We obtained occurrence points for 28 bumblebees (23 species and 5 subspecies) from the Atlas of European bees (Rasmont 2015). We derived a distribution range for each species from its occurrence points using the freely accessible map ‘Admin-1 State and provinces' of the Natural Earth database (nauralearthdata.com). The map contains data on internal first order administrative boundaries worldwide, with a resolution of 1:10m. We performed an intersection between the species occurrence points and the administrative boundaries map, retaining only the regions of the map intersected by the species occurrence points. We linked the species to their natural habitat using Copernicus Global Land Service Land Cover (CGLS-LC100) 2019 classes as a habitat surrogate. Species-Habitat associations and altitude limits were based on the current knowledge of the biology of target species, as referenced in scientific literature and species datasets. A binary classification was compiled to link species habitat  to land cover classes. Altitude limits (minimum and maximum) were compiled for each species. The CGLS-LC100 map was combined with altitude information from the Shuttle Radar Topography Mission (USGS EROS Archive 2019) to produce a base map. We used the species ranges to mask the area of the base map which is found out of the species range. The base map was reclassified according to species' habitat requirements to produce the AOH maps.