Introduced and Autochthonous Rodents in an Urban Landscape Context: Modeling Relative Abundance in Rodent Communities with Hantavius Reservoirs

CAVIA R; HERCOLINI C; TETA P; ZAMERO M; FERNÁNDEZ MS; MUSCHETTO E; CUETO G; SUÁREZ OV

Buenos Aires

Conferencia; VII Internacional Confeence on HFRS, HPS and Hantaviruses; 2007

Fundacion Mundo Sano

We modeled relative abundance of rodent species according to landscape structure in communities where Rattus norvegicus, R. rattus (both SEOUL hantavirus reservoirs) and Oligoryzomys flavescens (ANDES hantavirus reservoir) are present. Relative abundance of rodent species was estimated, between October 2002 and December 2005; in nine sites at Buenos Aires City (an urban reserve, three urban parklands, three urban shantytowns and two urban residential neighborhoods) by live trapping using similar Sherman and cage traps. The proportion of different land-cover types was used to characterize landscape structure in each site. On total 413 rodents were caught in 5462 Sherman traps-night and 5211 cage traps-night.  Rodents belonged to seven species, the autochthonous: O. flavescens, Deltamys  kempi, Calomys  musculinus and Cavia  aperea; and the introduced: R. norvegicus, R. rattus and Mus  musculus. According to Czekanowski quantitative index, most similar communities were present in parklands and shantytowns (both dominated by R. norvegicus and M. musculus). In parklands, O. flavescens and C. aperea were also captured. The communities of urban neighbourhoods were the most different ones (dominated by R. rattus). The urban reserve showed the highest richness, diversity and number of autochthonous rodents. Generalized Linear Models showed that the community representativity of R. norvegicus increased with the increasing surface occupied by urban areas with high proportion of vegetation and by water bodies; and with the decreasing surface occupied by herbs in the landscape unites. The representativity of M. musculus increased with the increasing surface occupied by herbs and trees, and the decreasing surface occupied by water bodies. The representativity of C. aperea increased with the decreasing surface occupied by urban areas with moderated proportion of vegetation and by trees. The representativity of O. flavescens increased with the increasing surface occupied by trees. We observed that, in rodent communities, species diversity, richness and autochthonous species representation decreased with the increasing of urbanization. Landscape structure explained more than 67 % of the deviance in the species representatively in each community. Our results are in accordance with the idea that the presence of different environments in a landscape acts as filters of a regional species pool and represent a tool to promote prevention actions and manage decisions involving reservoirs of hantaviruses.