CONICET | Buscador de Institutos y Recursos Humanos

Rodents have a high reproductive potential that allow them to reach, in many systems, pest level densities and can inflict economic and sanitary damages. This occurs, in particular, in human modified environments, where food and shelter is highly available and/or conditions are favourable, like houses, sheds, cultivated fields, etc.,. The aim of the Population Ecology Laboratory of the Exact and Natural Science Faculty of the University of Buenos Aires consists on studying rodents in rural and urban systems in order to contribute to the knowledge of theoretical and applied aspects of their ecology. The studies implicate the capture and recapture of rodents using Sherman (for small rodents) and cage traps (for rats) in cultivated fields and poultry farms in a rural system of Buenos Aires Province, and in Buenos Aires city (Argentina). Samples in fields started in 1979, on poultry farms in 1997 (this is a relative new industry in Argentina), while in the city started in 2001. Native sylvan and introduced domestic species are captured in the three systems, but the composition of species is different in each community. In field systems, the sylvan Cricetidae Calomys laucha and Calomys musculinus are numerically dominant in the crops, which are highly disturbed at certain moments of the year as during harvest activities. The sylvan Cricetidae Akodon azarae and Oligoryzomys flavescens, and the Caviidae Cavia aperea are more abundant in less disturbed habitats like field borders. The Cricetidae Oxymycterus rufus is only captured in field borders near water bodies during rainy years. The introduced Muridae Mus musculus, Rattus rattus and Rattus norvegicus are rare in both fields and borders, while they are the most abundant species surrounding the breeding sheds on poultry farms, specially M. musculus and R. norvegicus, while R. rattus is less captured. Sylvan rodents are also captured in poultry farms, but they are more abundant along the vegetated fences of the farms than surrounding the breeding sheds. Among these species, the most abundant is A. azarae, although C. laucha, C. musculinus and O. flavescens are also found, and O. rufus, like in the field system, is occasionally captured. C. laucha is captured in poultry sheds when there are harvest activities in the surrounding cropfields. In the urban system, R. rattus is dominant in residential-industrial areas, while R. norvegicus and M. musculus in parklands (where the sylvan O. flavescens and C. aperea are also present) and marginal neighbourhoods. The Cricetidae Deltamys kempi and O. flavescens are the dominated species in a urban reserve. Richness is very similar among the three systems (8 species in fields and poultry farms; 7 in the city), but the composition and/or relative proportion of species is different. The distribution of each species into each community mainly depends on its ability in afford human disturbance or, on the contrary, in get advantage of human products. Thus, the introduced species, M. musculus and the Rattus species show a growing dominance from the less disturbed system to the most modified by humans (the city). Among the cricetidaes, those which are more tolerant to human disturbances, as the Calomys species, are more abundant in crops (in contrast with the vegetated borders) and can also occupy the sheds in poultry farms, while A. azarae, a less tolerant species, is only abundant in the vegetated borders of fields or farms. O. flavescens, D. kempi and O. rufus are sylvan species associated with water bodies. Neither of them is very abundant in any of the studied systems, but in sites which are near rivers (including the urban reserve, which is located next to the River Plate) or in very humid years.

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