Seasonal variation of Abrothrix xanthorhinus reproduction and plant cover in a Stipa speciosa grassland in northwestern Patagonia.

GHERMANDI L. & GUTHMANN N. 2000.

International Journal of Ecology and Environmental Sciences

Año: 2000 p. 165 - 171

This study tested the hypothesis that there is a correlation between the reproduction of Abrothrix xanthorhinus and the seasonal growth of vegetation in gaps of a Stipa speciosa grassland in Northwestern Patagonia. Vegetation cover was measured monthly in ten gaps selected at random, from October to April in a 1993-1995 period. Rodents were sampled montly in the same study area of 1 ha using a 10x10 grid of Sherman traps. Significant differences between sampling date were detected in Vulpia australis, Erophila verna and total vegetation covers. The proportion of reproductive individuals of A. xanthorhinus differed significantly between months and was positively correlated with photoperiod length, total vegetation cover and cover of V. australis. It was found a significant multiple regression between total vegetation cover , photoperiod length and precipitation. In this study we have verified the existence of a correlation between the reproductive activity of A. xanthorhinus and the marked seasonal changes in the vegetation cover gaps.