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Late Quaternary climatic vegetational shifts in an ecological transition zone of northern M adagascar: insights from genetic analyses of two endemic rodent species
Author(s) -
Rakotoarisoa J.E.,
Raheriarisena M.,
Goodman S. M.
Publication year - 2013
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/jeb.12116
Subject(s) - ecology , biology , phylogeography , biome , quaternary , subfossil , population , coalescent theory , holocene , ecosystem , phylogenetics , paleontology , biochemistry , demography , sociology , gene
The L oky‐ M anambato region, located in northern M adagascar, is a biotically rich contact zone between different forest biomes. Local current forest cover is composed of both humid and dry formations, which show elevational stratification. A recent phylogeographical study of a regional dry forest rodent, E liurus carletoni (subfamily N esomyinae), found genetic evidence of forest contractions between 18 750 and 7500 years BP, which based on extrapolation of the pollen subfossil record, was thought to be associated with an expansion of local humid forests. Herein, we conduct a genetic test of this hypothesis and focused on populations on two neighbouring massifs of forest‐dependent rodent species, one associated with low‐elevation dry forests ( E . carletoni ) and the other with higher elevation humid forests ( E liurus tanala ). Using mitochondrial markers and a combination of traditional and coalescent‐based phylogeographical, historical demographic and population genetic methods, we found evidence of historical connections between populations of E . tanala . Adjacent populations of E . carletoni and E . tanala exhibit opposite historical demographic patterns, and for both, evidence suggests that historical demographic events occurred within the last 25 000 years BP. These findings strongly support the proposed late Quaternary shifts in the floristic composition of the L oky‐ M anambato region.