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

VERA, NOELIA SOLEDAD; CHIAPPERO, MARINA BEATRIZ; PRIOTTO, JOSÉ WALDEMAR; SOMMARO, LUCÍA VALERIA; STEINMANN, ANDREA ROSA; GARDENAL, CRISTINA NOEMÍ

MAMMALIAN BIOLOGY

ELSEVIER GMBH

Año: 2019 vol. 98 p. 52 - 60

1616-5047

tAgroecosystems in central Argentina are a good example of landscape modification by human activities.We used the Pampean grassland mouse (Akodon azarae) as a biological model to assess the effects oflandscape fragmentation on the genetic structure of natural populations present in the region. The speciesis a habitat specialist that is numerically dominant in relatively stable environments, such as remnantareas of native vegetation, stream borders, roadsides and railway banks. We used seven microsatelliteloci to analyze the genetic population structure and to explore if there is sex-biased dispersal during thereproductive season at a fine geographical scale. Rodents were captured seasonally in trap lines located onroadsides in an agroecosystem of central Argentina. Values of genetic differentiation among populationsand temporal patterns of spatial autocorrelation revealed that the genetic populations occupy areas largerthan the sampling area. Causal modeling analyses showed that unfavorable habitats (secondary roadsand crop fields) were not barriers to dispersal of Akodon azarae. The high levels of gene flow and theshort duration of the low population density phase, followed by a fast recovery, would contribute to themaintenance of highly polymorphic populations. As expected for A. azarae?s mating system, males werenot genetically structured. However, females? spatial genetic structure varied greatly over the year, whichwould be related to availability and quality of habitat, and to intrasex interactions. Our work contributesto the understanding of dispersal strategies in small mammals in anthropogenically fragmented habitatslike intensively managed agroecosystems.