Faunal patterns in Tuscan archipelago butterflies (Lepidoptera): The dominant influence is recent geography not paleogeography

Leonardo DAPPORTO,Alessandro CINI

doi:10.14411/eje.2007.070

Abstract

The aim of this paper is to examine whether current and/or Pleistocene geography affect the species richness and composition of Tuscan archipelago butterflies. This archipelago is located between Tuscany (Italy) and Corsica (France). Faunistic data was obtained from the literature and surveys. Our data revealed that contemporary geography is the most important factor determining the species richness and faunal composition of Tuscan archipelago butterflies. Indeed, current area and isolation of the islands are the only predictors significantly correlated with species richness. Paleogeographic features of the archipelago are not significantly correlated with species richness. Multidimensional scaling revealed patterns similar to those reported for other living groups. Specifically, Capraia and Montecristo group together with Corsica, while Elba, Giglio, Pianosa, Gorgona, Giannutri and the fossil island of Monte Argentario group with the Tuscan mainland. Recent geography seems to affect the faunal composition. Indeed Mantel test indicates that the similarity in the faunal composition of the Tuscan Archipelago islands is mainly related to present-day island characteristics and their relative distance from Tuscany and Corsica. Our results are similar to those recently obtained for Aegean archipelago butterflies.

Highlights

Many studies have been carried out on the biogeography of the Mediterranean basin, mainly focussing on whether ecological factors or paleogeographic history dominate species richness and distribution in Mediterranean archipelagos (Palmer et al, 1999; Welther-Schultes & Williams, 1999; Dennis et al, 2000; Garcia-Barros et al, 2002; Sammartín, 2003; Gentile &Argano, 2005; Hausdorf & Hennig, 2005)
Mantel test indicates that the similarity in the faunal composition of the Tuscan Archipelago islands is mainly related to present-day island characteristics and their relative distance from Tuscany and Corsica
Most of these authors linked the biogeographical features of the Tuscan archipelago fauna and flora to paleogeographic events that occurred with the disjunction and rotation of the Corsica-Sardinia microplate (Alvarez, 1972) and the earlier Pleistocene sea regressions (Bossio et al, 2000)

Summary

Introduction

Many studies have been carried out on the biogeography of the Mediterranean basin, mainly focussing on whether ecological factors or paleogeographic history dominate species richness and distribution in Mediterranean archipelagos (Palmer et al, 1999; Welther-Schultes & Williams, 1999; Dennis et al, 2000; Garcia-Barros et al, 2002; Sammartín, 2003; Gentile &Argano, 2005; Hausdorf & Hennig, 2005). The paleogeographic events that have occurred since the Miocene, and the different present-day distances between these islands and the coasts of Corsica and Tuscany (Italy), have resulted in a transitional fauna and flora; the co-occurrence of continental species and Sardinian and Corsican endemic species present an interesting puzzle (Società Italiana di Biogeografia, 1974; Jutzeler et al, 1996; Dapporto et al, 1999; 2002, 2003; Strumia, 2003) Most of these authors linked the biogeographical features of the Tuscan archipelago fauna and flora to paleogeographic events that occurred with the disjunction and rotation of the Corsica-Sardinia microplate (Alvarez, 1972) and the earlier Pleistocene sea regressions (Bossio et al, 2000). According to the most recent paleogeographical reconstructions, the lower sea level during the Würm Pleistocene glacial maxima resulted in Elba, Pianosa, Giannutri and possibly Giglio becoming connected with mainland Tuscany (Fig. 1)

Objectives

Results

Conclusion