Feeding patterns of capybara Hydrochaeris hydrochaeris (Rodentia, HYDROCHAERIDAE) and cattle in the non-insular area of the Lower Delta of the Paraná River, Argentina

QUINTANA, RUBEN DARIO; MONGE, SUSANA; MALVAREZ, ANA INES

MAMMALIA

WALTER DE GRUYTER & CO

Lugar: Berlin; Año: 1998 vol. 62 p. 37 - 52

0025-1461

Feeding habits of capybaras and cattle living in the non insular area of the Lower Delta region were studied. In addition, samples from coypu were also analyzed. This study was made using a microhistological analysis of faeces. Facces samples were taken seasonally during 2 years, between 1991 and 1993. The results showed that Poaceac was the main consumed group throughout the year for both capybara& and cattle, with the exception of winter, where catúe consumed a higher proportion of Cyperaceae. For the three herbivores, only a few items constituted the most important contribution to the diets. Five food items (Cynodon dactyIon, Panicum grumosum, Luziola peruviana, Zúaniopsis bonariensis and Eleocharis spp.) represented more than 60 % of the diet for both capybara. and cattle in every season. A similar foraging pattern was shown by both herbivores during the 2 years. Capybara and catúe diet compositions during the same season were similar, except in summer, when both diets were different. This last fact was also observed when the winter diets of the fírst two herbivores were compared with that of coypus. With the exception of summer, the seasonal trophic niche breadtIts were similar between capybaras and cattie. However, their values would be indicating a relatively narrow niche in every season, defining both herbivores as selective species. In contrast, coypus can be defined as more generalistic species although they exhibit a less diverse diet than the others. Total and specific tropItic niche overlap values suggest that during the critical season (winter), the foraging habits of capybaras and catfie would diverge, compensating for the low plant availability. In the other seasons, the increase in plant availability would lead to a situation of high overlap in the use of resources.