Influence of livestock grazing on the capybara’s trophic niche and forage preferences

Abstract

Trophic niche parameters and forage preferences of capybaraHydrochaeris hydrochaeris Linnaeus, 1766 were studied at three areas of east-central Argentina: Lower Delta Islands (LDI), only capybara present; Puerto Constanza (PC), capybara and cattle, and Villaguay (VI), capybara, cattle and sheep. Significant correlation was found in the annual botanical composition of capybara faeces at LDI and PC, but no correlation was found between faecal composition at these two areas and those at VI. The narrowest trophic niche corresponded to LDI, while the widest corresponded to VI, with significant differences in the values among the three areas. Capybara consumedCarex riparia, Cynodon dactylon andPanicum grumosum in LDI, andP. milioides in VI in proportion greater than availability. Three and eight food items were consumed less than availability in VI and PC, respectively. The greater the species number and density of livestock animals, the more generalist the behavior of capybara, possibly due to direct interaction in the use of grazing resources. Changes in availability of foraging species may influence the capybara’s preference patterns and the consumption of suboptimal feeding items may indicate a greater pressure on foraging resources in the areas where capybaras share their habitat with livestock.