Biogeography of western Mediterranean butterflies: combining turnover and nestedness components of faunal dissimilarity. (3rd April 2014)

• Record Type: Journal Article
• Authors: Dapporto, Leonardo; Fattorini, Simone; Vodă, Raluca; Dincă, Vlad; Vila, Roger; Fernández‐Palacios, José María
• Is Part Of: Journal of biogeography. Volume 41:Number 9(2014:Sep.)
• Page Start: 1639
• Page End: 1650
• Publication Date: 2014-04-03
• Subjects: Biogeography -- Periodicals; 578.09
• DOI: 10.1111/jbi.12315
• Languages: English
• ISSNs: 0305-0270

Abstract

<abstract abstract-type="main" id="jbi12315-abs-0001"> <title>Abstract</title> <sec id="jbi12315-sec-0001" sec-type="section"> <title>Aim</title> <p>Unpartitioned dissimilarity indices such as the Sørensen index (β<sub>sor</sub>) tend to categorize areas according to species number. The use of turnover indices, such as the Simpson index (β<sub>simp</sub>), may lead to the loss of important information represented by the nestedness component (β<sub>nest</sub>). Recent studies have suggested the importance of integrating nestedness and turnover information. We evaluated this proposition by comparing biogeographical patterns obtained by unpartitioned (β<sub>sor</sub>) and partitioned indices (β<sub>simp</sub> and β<sub>nest</sub>) on presence data of western Mediterranean butterflies.</p> </sec> <sec id="jbi12315-sec-0002" sec-type="section"> <title>Location</title> <p>Western Mediterranean.</p> </sec> <sec id="jbi12315-sec-0003" sec-type="section"> <title>Methods</title> <p>We assessed the regionalization of 81 mainland and island faunas according to partitioned and unpartitioned dissimilarity by using cluster analyses with the unweighted pair‐group method using arithmetic averages (UPGMA) combined with non‐metric multidimensional scaling (NMDS). We also carried out dissimilarity interpolation for β<sub>sor</sub>, β<sub>simp</sub>, β<sub>nest</sub> and the β<sub>nest</sub>/β<sub>sor</sub> ratio, to identify geographical patterns of variation in faunal dissimilarity.</p> </sec> <sec id="jbi12315-sec-0004" sec-type="section"> <title>Results</title> <p>When the unpartitioned β<sub>sor</sub> index was used, the clustering of sites allowed a clear distinction between insular and mainland species assemblages. Most islands were grouped together, irrespective of their mainland source, because of the dominant effect of their shared low richness. β<sub>simp</sub> was the most effective index for clustering islands with their respective mainland source. β<sub>simp</sub> clustered mainland sites into broader regions than clusters obtained using β<sub>sor</sub>. A comparison of regionalization and interpolation provided complementary information and revealed that, in different regions, the patterns highlighted by β<sub>sor</sub> could largely be determined either by nestedness or turnover.</p> </sec> <sec id="jbi12315-sec-0005" sec-type="section"> <title>Main conclusions</title> <p>Partitioned and unpartitioned indices convey complementary information, and are able to reveal the influence of historical and ecological processes in structuring species assemblages. When the effect of nestedness is strong, the exclusive use of turnover indices can generate geographically coherent groupings, but can also result in the loss of important information. Indeed, various factors, such as colonization–extinction events, climatic parameters and the peninsular effect, may determine dissimilarity patterns expressed by the nestedness component.</p> </sec> </abstract>