This press release is available in Spanish.
Scientists from the Biological Station of Doñana (CSIC) and the have characterized the population genetic diversity of an animal species (a mouse, in this case) in its whole distribution. This information is essential for developing successful conservation plans for such species.
This work was conducted by Alejandro Centeno Cuadros at the Doñana Biological Station (CSIC) in Sevilla, and the Department of Animal Biology of the University of Granada. His work was directed by doctors Jose Antonio Godoy and Miguel Delibes from the Doñana Biological Station, who jointly addressed a population and phylogeographic genetic study of the water vole (Arvicola sapidus) in its whole distribution (France and the Iberian Peninsula).
This research has shown that it is necessary to study the DNA in three hierarchical scales: individual, population and species, in order to understand the current genetic distribution of animal species. It also urges managers and scientists to embrace these levels of study because, Alejandro Centeno Cuadros warns, as in the case of habitat quality and population status, "agencies responsible for management and conservation of species must also seek to preserve their genetic diversity".
The most comprehensive study
So far, a study had never before been conducted that addressed the complete genetic component on the species. "More importantly –the researcher points out– is that we have covered distribution patterns of genetic diversity of water voles, both in its whole distribution and as local populations in heterogeneous environments, like in Doñana natural environment, obtaining DNA from bones to individuals tricked by our research group."
Thus, this work has deepened the understanding of the natural history of this protected species from previous research carried out by the International Union for Conservation of Nature (IUCN). Now there is enough information to properly develop conservation plans for the species, thanks to the information about the genetic component of the species that Centeno Cuadros has brought out.
To carry out this investigation, Centeno Cuadros obtained DNA from bones of water voles preyed on by raptors and museum material, fur of water voles from national and international scientific collections, and fresh tissue obtained in populations of water voles in the Doñana Natural Region and in the Río Bergantes (Castellón) environment.
From 250,000 years ago
Researchers have determined what happened to water vole from its origins up to the present population behaviour by studying distribution of genetic diversity. To this end, they achieved representative samples from its whole distribution (France and the Iberian Peninsula), as they were able to obtain DNA from bones found primarily in raptor pellets (regurgitated composed of undigested food debris) that were fed on water voles.
Because of this, they consider that the origin of this rodent species occurred in Iberia in the late Middle Pleistocene (250,000 years ago) as a result of isolation in the Iberian Peninsula of its ancestor species, which fled from heavy falls in temperature and advancing ice from North to South Europe during the Mindel Glaciation.
Scientists have found no evidence that landscape exerts strong influence on the genetic structure of water vole populations, contrary to expectations generated by a species described as habitat specialist. This dispersive behaviour may be a strategy of habitat specialists, whose population survival and persistence in space and time, will depend on their ability to colonize best areas for breeding, in the case of water voles, separated by great distances, far exceeding the expected for a rodent of its size.
Alejandro Centeno Cuadros stresses that the results of this research "should be considered for developing conservation plans and thus ensuring the survival of the genetic diversity of this species. In fact, water vole is listed as "Vulnerable" by the International Union for Conservation of Nature.
References:
Centeno-Cuadros, A, Delibes, M, Godoy, J. A. (2009), «Phylogeography of Southern Water Vole (Arvicola sapidus): evidence for refugia within the Iberian glacial refugium?», Molecular Ecology, 18, 3652-3667.
Centeno-Cuadros, A, Delibes, M, Godoy, J. A. (in press), «Dating the divergence between Southern and European water voles using coalescent-based methods», Journal of Zoology, DOI: 10.1111/j.1469-7998.2009.00632.x
Journal
Molecular Ecology