Endemism is the phenomenon whereby certain plant or animal species are exclusive to a given territory. Although, technically, the term endemism can also be applied to vast territories, such as entire continents, endemisms relating to very restricted areas such as islands, sometimes covering only a few square kilometres, are of interest.
Endemic species can be found together in two cases: either because they evolved in the same place where we find them now and persist regionally; or because they evolved in different places and subsequently dispersed into shared habitats, generating centres of endemicity.
In their paper "Two ways to be endemic. Alps and Apennines are different functional refugia during climatic cycles" published in Molecular Ecology, Menchetti et al. evaluated the possible existence of endemicity hotspots in the region from the Alps to Sicily by studying their butterfly fauna.
By sequencing the DNA of 26.557 butterflies from 269 species in the Western Palearctic, the researchers derived a zoogeographic regionalisation based on the 69 endemics of the area. Endemicity showed a high incidence in the Alps and Southern Italy. The regionalisation thus determined separates the Alps from the Italian peninsula and Sicily. In addition, the variation identified as palaeoendemic (i.e. elderly) the Alpine endemics, today occupying an ecological centre, and as neoendemic those from the rest of the peninsula and Sicily, which have differentiated in the region since the Pleistocene.
These results contradict the common view of an Alpine-Apennine area seen as the only "Italian refuge", demonstrating the presence of considerable differences within Italian endemisms.
