Demography and microhabitat use of the wild guinea pig(Cavia aperea) in freshwater Spartina densiflora marshes in Argentina
Stella M. BONAVENTURA ①* Verónica PANCOTTO② Ricardo L. VICARI① Nora MADANES① María I. BELLOCQ① (① Department of Ecology, Genetics and Evolution, University of Buenos Aires, Argentina) (② Department of Ecology, Faculty of Agronomy, University of Buenos Aires, Argentina)
We studied abundance, reproduction and microhabitat use of the wild guinea pig (WGP), Cavia aperea, and its influence on vegetation and sigmodontine rodents during the fall-winter period in freshwater Spartina densiflora marshes. WGP preferred microhabitats with high S. densiflora cover. Reproductive individuals (=adults) mainly used patches dominated by short grasses, while juveniles used patches with forbs. These results suggest that microhabitat use in the WPG is influenced by predation risk (availability of safe foraging sites and refuges) and type of food. In freshwater marshes, WGP abundance, reproduction, body weight and microhabitat use exhibited no seasonal variations, and their herbivory and runway construction activities had no negative effect on vegetation structure and sigmodontine rodents. Results from a comparison between WGP populations living in freshwater habitats (moderate seasonality) vs grasslands and roadsides (strong seasonality), suggest that the population dynamics of the WGP, as well as the impact of the WGP population on vegetation and on coexisting rodent communities, are influenced by the availability of plant cover during winter[Acta Zoologica Sinica 49(1):20-31,2003].