Diet of a fossorial rodent (Octodontidae), above-ground food availability, and changes related to cattle grazins in the Central Monte (Argentina)

ROSI, M. I.; PUIG , S.; CONA , M. I.; VIDELA, F.; MÉNDEZ, E.; ROIG, V. G.

Journal of Arid Environments

S&T Editorial Services (Elsevier Ltd.)

Año: 2008 vol. 73 p. 273 - 279

0140-1963

Abstract:  Diet of a fossorial rodent (Octodontidae), above-ground food availability, and changes related to cattle grazing in the Central Monte (Argentina).  Overgrazing by livestock has caused desertification in the Monte, where ctenomyids and livestock share grasses as main food items. The diet of Ctenomys eremophilus, above-ground food availability and  changes related to cattle grazing are analyzed in the arid plain of Mendoza, Argentina. The most available categories were grasses, followed by low shrubs and tall shrubs. Tuco-tucos showed dietary generalism, ate mainly above-ground plants parts, preferred grasses and avoided shrubs at both grazed and ungrazed sites. Plant cover, grass diversity and availability decresead under livestock grazing, which was reflected  in the diet by a lower percentage of grasses, a shift toward low shrubs and higher  number of frequently used resources. Tuco-tucos in the grazed paddock compensated  for  lower consumption  of vegetative plant parts by increasing the use  of Prosopis flexuosa  pods  stored inside burrows. Moreover, greater dietary variation among individuals suggests foraging restricted to the items closest to burrow holes. These feeding tactics would allow them to reduce above-ground foraging as a response to high raptor predation risk due to increased bare soil. The plant recovery detected during the rest period, favoured by moderate stocking rate and rotational grazing system, would allow coexistence of tuco-tucos and cattle.