Modeling the spatial structure of the endemic mara ( Dolichotis patagonum ) across modified landscapes

Abstract

Across modified landscapes, anthropic factors can affect habitat selection by animalsand consequently their abundance and distribution patterns. The study of thespatial structure of wild populations is crucial to gain knowledge on species? responseto habitat quality, and a key for the design and implementation of conservationactions. This is particularly important for a low-density and widely distributedspecies such as the mara (Dolichotis patagonum), a large rodent endemic toArgentina across the Monte and Patagonian drylands where extensive sheepranching predominates. We aimed to assess the spatial variation in the abundance ofmaras and to identify the natural and anthropic factors influencing the observedpatterns in Península Valdés, a representative landscape of Patagonia. We conductedground surveys during the austral autumn from 2015 to 2017. We built densitysurface models to account for the variation in mara abundance, and obtained a mapof mara density at a resolution of four km2. We estimated an overall density of0.93 maras.km-2for the prediction area of 3,476 km2. The location of ranchbuildings, indicators of human presence, had a strong positive effect on theabundance of maras, while the significant contribution of the geographic longitudesuggested that mara density increases with higher rainfall. Although humanpresence favored mara abundance, presumably by providing protection againstpredators, it is likely that the association could bring negative consequences for marasand other species. The use of spatial models allowed us to provide thefirstestimate of mara abundance at a landscape scale and its spatial variation at ahigh resolution. Our approach can contribute to the assessment of mara populationabundance and the factors shaping its spatial structure elsewhere across the speciesrange, all crucial attributes to identify and prioritize conservation actions