Genetic structure of populations of the Pampean grassland mouse, Akodon azarae, in an agroecosystem under intensive management

VERA, N.S.; CHIAPPERO, M.B.; STEINMANN, A.R.; PRIOTTO, J.W.; GARDENAL, C.N.

MAMMALIAN BIOLOGY

ELSEVIER GMBH

Año: 2019 vol. 98 p. 52 - 60

1616-5047

Agroecosystems of southern Cordoba province are a good example of the process of habitat fragmentation. In order to assess the effects of landscape fragmentation on the genetic structure of natural populations inhabiting the region, we used Akodon azarae as a biological model. The species is a habitat specialist, numerically dominant in relatively stable environments such as remnant areas of native vegetation, stream borders, roadsides and railway banks. We used 7 microsatellite loci to analyze the genetic structure and the possible sex biased dispersal during the reproductive season at fine geographical scale. Rodent captures were seasonally in trap lines located on roadsides in an agroecosystem of central Argentina. Values of genetic differentiation among populations and temporal patterns of spatial autocorrelation revealed that the limits of genetic populations are larger than the extension of the sampled area. Causal modeling analyses showed that unfavorable habitats (secondary roads and crop fields) do not constitute real barriers to dispersion of Akodon azarae individuals and that genetic differentiation between individuals is influence mainly by geographic distance. The high levels of gene flow and the short duration of the low population density phase would contribute to the maintenance of highly polymorphic populations. As expected by A. azarae?s mating system, males were not genetically structured. However, females? spatial genetic structured varied greatly along the year, which would be related to availability and quality of habitat, and to intrasex interactions. Our work contributes to the understanding of dispersal strategies in small mammals in anthropogenically fragmented habitats like intensively managed agroecosystems.