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The role of dispersal and vicariance in the P leistocene history of an E ast A frican mountain rodent, P raomys delectorum
Author(s) -
Bryja Josef,
Mikula Ondřej,
Patzenhauerová Hana,
Oguge Nicholas O.,
Šumbera Radim,
Verheyen Erik
Publication year - 2014
Publication title -
journal of biogeography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 158
eISSN - 1365-2699
pISSN - 0305-0270
DOI - 10.1111/jbi.12195
Subject(s) - vicariance , allopatric speciation , biological dispersal , ecology , phylogeography , range (aeronautics) , pleistocene , biology , biogeography , geography , paleontology , population , phylogenetics , demography , biochemistry , sociology , gene , materials science , composite material
Abstract Aim Species living in East African montane forests have highly fragmented distributions. P lio‐ P leistocene climatic cycles, however, may have allowed temporary contact between forest blocks, thereby allowing gene flow. Our aim was to reconstruct the colonization history of P raomys delectorum , a rodent species adapted to montane forests. We tested two alternative scenarios: (1) the occurrence of a series of vicariance events related to Quaternary climatic changes; and (2) colonization from a single origin through successive dispersal events. Location Montane forests of E ast A frica. Methods Analyses were based on large‐scale sampling covering the complete range of the species distribution. We assessed genetic structure and historical demography using a combination of mitochondrial and nuclear markers. Morphological differences between allopatric populations were analysed using a geometric morphometric approach. Results Populations of P . delectorum are genetically differentiated along the north–south axis of the distribution range, consistent with postulated vicariance events. The oldest vicariance event, which separated the species into three main genetic groups, dates to the beginning of the Pleistocene. Further fragmentation within the three main lineages is consistent with successive vicariance events, probably linked to P leistocene climatic cycles. Morphological variation between geographically structured populations may indicate local environmental adaptations. Main conclusions The most likely explanation for the strong genetic differentiation among fragmented populations is a series of vicariance events caused by periodic fragmentation of montane forests that resulted from climatic oscillations in the P leistocene, rather than successive dispersal events. The recently proposed splitting of P . delectorum into three allopatric morphospecies only partly reflects the observed genetic structure.