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

MARIA ROSI; SILVIA PUIG; MÓNICA I. CONA; MENDEZ E.

JOURNAL OF ARID ENVIRONMENTS

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2009

0140-1963

Overgrazing by livestock has caused desertification in the Monte, where ctenomyids and livestock sharegrasses as main food items. The diet of Ctenomys eremophilus, above-ground food availability andchanges related to cattle grazing are analyzed in the arid plain of Mendoza, Argentina. The most availablecategories were grasses, followed by low shrubs and tall shrubs. Tuco-tucos showed dietary generalism,ate mainly above-ground plant parts, preferred grasses and avoided shrubs at both grazed and ungrazedsites. Plant cover, grass diversity and availability decreased under livestock grazing, which was reflectedin the diet by a lower percentage of grasses, a shift toward low shrubs and higher number of frequentlyused resources. Tuco-tucos in the grazed paddock compensated for lower consumption of vegetativeplant parts by increasing the use of Prosopis flexuosa pods stored inside burrows. Moreover, greaterdietary 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 raptorpredation risk due to increased bare soil. The plant recovery detected during the rest period, favoured bymoderate stocking rate and rotational grazing system, would allow coexistence of tuco-tucos and cattle.