Habitat selection and density effect on Akodon azarae and Calomys laucha (Mammalia, Rodentia, Muridae). Studies on Neotropical Fauna and Environment, 29 (2): 113-123. ISSN:

DE VILLAFAÑE, GLORIA; QUINTANA, RUBEN DARIO; MERLER, JORGE ALBERTO; BONAVENTURA, STELLA

STUDIES ON NEOTROPICAL FAUNA AND ENVIRONMENT

TAYLOR & FRANCIS LTD

Lugar: Londres; Año: 1994 vol. 29 p. 113 - 123

0165-0521

Three experiments in semicaptivity were made, in three enclosures, on habitat selection of A. azarae and C. laucha to different densities. In each enclosure three types of habitat were planted: cultivated field edges, soya and corn stubble. One week after the rodents were released, 35 Sherman´s traps were exposed for three days and controlled twice per day. In experiments I and II, the effect of density on the spatial distribution of C. laucha and A. azarae alone, was studied. Males and females were released in proportional amounts and their respective densities ranged from 4 to 6 and 12 individuals per enclosure; that equals 833, 1,250 and 2,500 rodents/Ha, respectively. In experiment III, the effect of several densities of C. laucha (4, 6 and 10 individuals/enclosure) on the spatial distribution of A. azarae at a fixed density (6 rodents/enclosure) was studied. The results of experiment I show that the distribution of C. laucha is significantly related to the type of habitat. Soya was used most frequently and the different densities do not show significant differences. In experiment II, it was observed that the spatial distribution of A. azarae is significantly affected by the type of habitat. This species prefers the microhabitat of soya and edge, and avoids the use of stubble. In experiment III, A. azarae, at low and medium densities of C. laucha, prefers the microhabitat of soya and edge, avoiding the stubble. It is important to emphasize that A. azarae is displaced to the edges when C. laucha is present at high densities.