Effect of plant cover on seed removal by rodents in the Monte desert (Mendoza, Argentina

TARABORELLI, P.; DACAR, M; GIANNONI STELLA

AUSTRAL ECOLOGY

Lugar: Australia; Año: 2003 vol. 28 p. 651 - 657

1442-9985

In desert areas, predation risk is one of the highest costs of foraging and is a major influence on animalbehaviour. Several strategies are used by foragers for surviving and reproducing in desert areas. The foragingstrategies of the small mammals of South American deserts are still poorly known. In this study, we investigated theforaging strategies of rodents of the Monte Desert in response to distance from seed sources to sheltered sites (i.e.shrubs) during two different seasons (wet and dry). We evaluated the relative rates of removal of two species of seeds(millet and sunflower) by rodents at two sites by establishing 80 seed sources, 40 in unsheltered microhabitats and40 in sheltered microhabitats. We recorded both the number of caches and seed consumption for each source. Wefound that plant cover affected the foraging activity of rodents of the sand dunes in the Monte Desert because bothconsumption and numbers of caches constructed from sheltered seed sources were higher than those fromunsheltered ones. Consumption of sunflower was higher in the wet season than it was in the dry season, when milletconsumption increased. Sunflower was the preferred seed both from sheltered or unsheltered sources. We discussthe possible causes of the different foraging strategies used by rodents of the Monte Desert.