Phylogeography of Crocidura suaveolens (Mammalia: Soricidae) in Iberia has been shaped by competitive exclusion by C. russula

Abstract

Despite their potential importance, biological processes such as competitive exclusion (CE) have been largely neglected in phylogeographical studies. Here, we analyse the role of glacial events and CE in the evolutionary history of the lesser white-toothed shrew, Crocidura suaveolens, in Iberia based on cytochrome b sequences. All the Iberian samples grouped together with the rest of western European populations within the previously described clade IV. We identified three distinct evolutionary lineages within this major clade, two of them occurring exclusively in Iberia. Iberian lineage B extends throughout the northwest with a continuous distribution and moderate to high diversity values, whereas Iberian lineage C has a highly patchy distribution and is structured in four sublineages, all having low diversity values. No signs of demographic growth were detected for any of the lineages. The evolutionary history of C. suaveolens in Iberia supports the refugia-within-refugia scenario, but ecological studies in areas of sympatry, molecular and fossil datings, and contrasting patterns in the Italian Peninsula suggest that CE exerted by C. russula since its arrival in Iberia has been the main factor shaping the distribution, phylogeography and population genetics of lineage C.