title: Seasonal flooding regime and ecological traits influence genetic structure of two small rodents.
abstract: Although codistributed species are affected by the same abiotic factors, such as rivers and seasonal flooding regimes, ecological traits, such as locomotion habits and habitat preferences, may also influence differences in levels of genetic diversity and differentiation. We examined population genetic structure and diversity of Hylaeamys megacephalus and Oecomys aff. roberti, two cricetid rodent species from the mid-Araguaia River in central Brazil, using mitochondrial DNA sequence data. Specifically, we aim to test whether the Araguaia River acts as a barrier to the gene flow of these two species and to assess how ecological traits, such as locomotion habits and habitat preferences, may influence differences in levels of genetic diversity and differentiation. As both species occur in flooded forests, neither showed genetic differences related to river banks. Oecomys aff. roberti showed stronger population structure that appears to be associated with isolation by distance. This arboreal species maintained stable populations in the Araguaia River, while the terrestrial H. megacephalus was more affected by seasonal floods, resulting in a genetic signature of population expansion. Our initial predictions were largely supported by our results given that locomotion habits and habitat preferences of each species appears to have played a role on the genetic structure of these two sympatric rodent species.
authors.affiliation: CESAM and Departamento de Biologia, Universidade de Aveiro Campus de Santiago, Aveiro, 3810-193, Portugal ; Laboratório de Mastozoologia e Biogeografia, Departamento de Ciências Biológicas, Centro de Ciências Humanas e Naturais, Universidade Federal do Espírito Santo Av Goiabeiras, 29075-910, Vitória, ES, Brazil.
authors.forename: Rita Gomes
authors.initials: RG
authors.lastname: Rocha
authors.affiliation: CESAM and Departamento de Biologia, Universidade de Aveiro Campus de Santiago, Aveiro, 3810-193, Portugal.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Ferreira
authors.affiliation: CESAM and Departamento de Biologia, Universidade de Aveiro Campus de Santiago, Aveiro, 3810-193, Portugal.
authors.forename: Carlos
authors.initials: C
authors.lastname: Fonseca
authors.affiliation: Núcleo de Genética Aplicada à Conservação da Biodiversidade, Departamento de Ciências Biológicas, Universidade Federal do Espírito Santo Av. Marechal Campos 1468, Maruípe, Vitória, 29043-900, Espírito Santo, Brazil.
authors.forename: Juliana
authors.initials: J
authors.lastname: Justino
authors.affiliation: Laboratório de Mastozoologia e Biogeografia, Departamento de Ciências Biológicas, Centro de Ciências Humanas e Naturais, Universidade Federal do Espírito Santo Av Goiabeiras, 29075-910, Vitória, ES, Brazil.
authors.forename: Yuri Luiz Reis
authors.initials: YL
authors.lastname: Leite
authors.affiliation: Laboratório de Mastozoologia e Biogeografia, Departamento de Ciências Biológicas, Centro de Ciências Humanas e Naturais, Universidade Federal do Espírito Santo Av Goiabeiras, 29075-910, Vitória, ES, Brazil.
authors.forename: Leonora Pires
authors.initials: LP
authors.lastname: Costa
keywords: Amazonia-Cerrado ecotone; Araguaia river; Cricetidae; Rodentia; mitochondrial DNA