Conserving biodiversity in fragmented and changing habitats: how many species of Ctenomys inhabit the Iberá wetland?

GOMEZ FERNANDEZ M.J; OSCAR E. GAGGIOTTI; KITTLEIN, MARCELO; MIROL, PATRICIA

Glasgow

Congreso; 3rd European Congress of Conservation Biology; 2012

European Section of the Society for Conservation Biology

The South American subterranean rodents Ctenomys are highly speciose, with 62 species that appeared in the lapse of 3 million years. Within the genus, the perrensi group, formed by three named species and a group of forms of unknown taxonomic status, inhabits the Iberá wetland, in northern Argentina, which changes periodically altering the ammount and disposition of suitable habitat for the species. In order to understand the evolutionary processes operating in the group, we examined mitochondrial DNA sequences and microsatellite genotypes. The mitochondrial DNA phylogeny evidenced two different groups, separated by one of the main rivers of the region. Clustering methods based on microsatellite genotypes, delimited 12 different populations and 5 metapopulation lineages. Some of the genetic clusters found included localities with very different chromosomal numbers, which points to the existence of gene flow despite chromosomal variation. A bayesian analysis revealed that habitat fragmentation is the only significant environmental factor shaping the genetic structure of the system. The evolutionary future of these five lineages seems to be tightly controlled by the dynamics of their habitat, if stable they may become distinct species, otherwise they may collapse into a hybrid swarm forming a single evolving metapopulation.