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

Abstract

In desert areas, predation risk is one of the highest costs of foraging and is a major influence on animal behaviour. Several strategies are used by foragers for surviving and reproducing in desert areas. The foraging strategies of the small mammals of South American deserts are still poorly known. In this study, we investigated the foraging 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 and 40 in sheltered microhabitats. We recorded both the number of caches and seed consumption for each source. We found that plant cover affected the foraging activity of rodents of the sand dunes in the Monte Desert because both consumption and numbers of caches constructed from sheltered seed sources were higher than those from unsheltered ones. Consumption of sunflower was higher in the wet season than it was in the dry season, when millet consumption increased. Sunflower was the preferred seed both from sheltered or unsheltered sources. We discuss the possible causes of the different foraging strategies used by rodents of the Monte Desert.

Influence of predation risk and plant structure on vigilance and intermittent locomotion in Microcavia australis (Rodentia, Caviidae)

“…Another antipredator behavior is the mode of locomotion employed by rodents, which plays a vital role in determining their ability to elude predators (Thompson 1985;Djawdan and Garland 1988;Taraborelli et al 2003a). The structural complexity of the habitat may affect movement behavior by: (1) physically impeding locomotion (Schooley et al 1996), (2) making movement more conspicuous and thus riskier (Brillhart and Kaufman 1991;Borruel et al unpublished data), (3) providing a higher density of resources, hence favoring lower speeds so that resource opportunities are not missed (Brownsmith 1977), (4) increasing protection against predators through hiding cover (Thompson 1982;Taraborelli et al 2003b), (5) increasing visual obstruction, thus reducing the ability to detect predators (Schooley et al 1996;Ebensperger and Hurtado 2005).…”

Seed consumption and caching on seeds of three sympatric tree species by four sympatric rodent species in a subtropical forest, China

“…Food abundance (Alm et al, 2002), seed size (Garb et al, 2000;Ivan and Swihart, 2000), hardness of seed hull (Sako et al, 2002), perishability (Post and Reichman, 1991;Hadj-Chikh et al, 1996), palatability or nutrient composition (Laska et al, 2003), secondary compounds (Dixon and Johnson, 1997), seed energetic value (Lewis et al, 2001) are important factors in influencing seed predation and hoarding by rodents. Body size, age, sex, social structure, food preference and predator avoidance of rodents (Kitchen et al, 1999;Arjo et al, 2002;Taraborelli et al, 2003;Vander Wall and Jenkins, 2003) are also important factors in influencing seed predation and hoarding by rodents.…”

Seed fate of Marah macrocarpus (Cucurbitaceae) following fire: do seedlings recruit from rodent burrows?

“…Only a few caches were present in areas devoid of shrub skeletons. Taraborelli et al (2003) similarly found that Argentine desert rodents cached more seeds near sheltered versus unsheltered sites. Shrub cover was scarce in the burn area over hundreds of hectares for the first 13 months after the fire.…”