Local and landscape habitat determinants of water vole distribution in a patchy Mediterranean environment
2002
Fedriani, Jose | Delibes, Miguel | Ferreras, Pablo | Roman, Jacinto
We studied the distribution of a water-dependent species (southern water vole, Arvicola sapidus) in a Mediterranean region (Doñana National Park, southwest Spain) characterized by a complex array of different-sized ponds (where voles were confined) embedded in a mostly unsuitable landscape. For each surveyed pond (n = 185), a total of 26 variables related to both local (20) and landscape (6) attributes were quantified, and the presence of voles was evaluated by finding their typical signs (latrines). We found signs of water voles in 60% of ponds, despite the fact that most of them (84%) were totally dried out. A generalized linear model analysis showed that water voles were sensitive to both local and landscape attributes of ponds. At a landscape scale, presence of voles was more likely in ponds located outside the national park, close to other ponds holding voles, and far away from areas rich in potential predators and competitors. At a local scale, ponds with water voles were characterized by abundant grasses, banks well covered by brushes, low altitude, and low abundance of rabbits (Oryctolagus cuniculus). We also studied the use of microhabitat by voles within four specific ponds and found that they preferred plots of higher vegetation cover; thus, there was consistency in some cues used by water voles at the population/subpopulation scale (among different ponds) and at the behavioral scale (within ponds). Our study strongly supports the notion that the entire vole population is structured in distinct subpopulations, which are affected by a hierarchy of processes ranging from metapopulation dynamics and influenced by the landscape within which ponds are embedded as well as the local habitat quality.
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