Two ways to be endemic. Alps and Apennines are different functional refugia during climatic cycles

Abstract

Endemics co‐occur because they evolved in situ and persist regionally or because they evolved ex situ and later dispersed to shared habitats, generating evolutionary or ecological endemicity centres, respectively. We investigate whether different endemicity centres can intertwine in the region ranging from Alps to Sicily, by studying their butterfly fauna. We gathered an extensive occurrence data set for butterflies of the study area (27,123 records, 269 species, in cells of 0.5 × 0.5 degrees of latitude‐longitude). We applied molecular‐based delimitation methods (GMYC model) to 26,557 cytochrome c oxidase subunit 1 (COI) sequences of Western Palearctic butterflies. We identified entities based on molecular delimitations and/or the checklist of European butterflies and objectively attributed occurrences to their most probable entity. We obtained a zoogeographic regionalisation based on the 69 endemics of the area. Using phylogenetic ANOVA we tested if endemics from different centres differ from each other and from nonendemics for key ecological traits and divergence time. Endemicity showed high incidence in the Alps and Southern Italy. The regionalisation separated the Alps from the Italian Peninsula and Sicily. The endemics of different centres showed a high turnover and differed in phylogenetic distances, phenology and distribution traits. Endemics are on average younger than nonendemics and the Peninsula‐Sicily endemics also have lower variance in divergence than those from the Alps. The observed variation identifies Alpine endemics as paleoendemics, now occupying an ecological centre, and the Peninsula‐Sicily ones as neoendemics, that diverged in the region since the Pleistocene. The results challenge the common view of the Alpine‐Apennine area as a single “Italian refugium”.

The interaction of climate history and evolution impacts alpine biodiversity assembly differently in freshwater and on land

“…Pleistocene refugia are hypothesized for terrestrial taxa in many geographically restricted areas on nunataks, i.e, mountain peaks that have never been glaciated [88], or surrounding the Alps [41,[89][90][91][92], such that extinctions during the glacial cycles did not wipe out the terrestrial fauna entirely. It is very likely that terrestrial organisms, particularly butterflies [41,93], plants [94][95][96] and amphibians [71,72] survived in glacial refugia in the Alps and at its periphery. Therefore, differential impacts of Quaternary climate fluctuations and the resulting glaciations on different habitats and taxa go a long way helping to explain extant patterns of diversity and endemism in the region.…”

“…We found that endemic species in the terrestrial groups are much older than endemic fish species. Pleistocene refugia are hypothesized for terrestrial taxa in many geographically restricted areas on nunataks, i.e, mountain peaks that have never been glaciated [88], or surrounding the Alps [41,[89][90][91][92], such that extinctions during the glacial cycles did not wipe out the terrestrial fauna entirely. It is very likely that terrestrial organisms, particularly butterflies [41,93], plants [94][95][96] and amphibians [71,72] survived in glacial refugia in the Alps and at its periphery.…”

“…The climatic and habitat instability driven by the Quaternary climate fluctuations [35] has interacted evolutionary and ecological processes to shape biodiversity in the Alps [34,[36][37][38][39][40][41].…”

“…Despite its large information content for investigating hypothesis regarding biodiversity assembly and to understand biogeographic patterns in species distributions [64], few studies have made use of the species age distribution (SAD) [41,65,66], and fewer had investigated SAD from a multi-taxon perspective [8,67]. We conducted a comparative phylogenetic analysis to quantify SADs and the extent and type of endemism in aquatic and terrestrial ecosystems of the European Alps.…”

Pruning the Barcode Index Numbers tree: Morphological and genetic evidence clarifies species boundaries in theEupithecia conterminatacomplex (Lepidoptera: Geometridae) in Europe

“…They often likely reflect past glacial refugial history, and their study has contributed to highlight colonization/extinction dynamics of European territory during glaciations. In particular, these dynamics seem to have been produced many endemic but morphologically indistinguishable lineages in the Italian Peninsula (Menchetti et al, 2021).…”