Population dynamics of five sigmodontine rodents of northwestern Patagonia

Population dynamics of five rodent species were studied, from March 1991 to August 1994, in an area located in the ecotonal steppe of northwestern Patagonia, Argentina (at about 40 degrees S). Seasonal and annual fluctuations in population numbers were found in all sigmodontine species. The reproductive period, sex ratio and longevity of the five species were also studied. Abrothrix xanthorhinus (Waterhouse, 1837), a habitat generalist, was the most abundant species. Eligmodontia morgani (Allen, 1901), Abrothrix longipilis (Waterhouse, 1837), Reithrodon auritus (Fischer, 1814) and Oligoryzomys longicaudatus (Bennett, 1832) were subdominant. The present study is a first description of the population dynamics in this rodent community, whose ecological characteristics gather importance considering that some of these species are Hantavirus reservoirs.