Feeding habitat of giant pandas (Ailuropoda melanoleuca): why do they prefer bamboo patch edges?

Abstract

The factors that affect the selection of feeding sites by giant pandas Ailuropoda melanoleuca in the Longxi-Hongkou Nature Reserve were explored in winter from 2000 to 2002, by using strip transects. It was reported in the literature that giant pandas prefer to forage on the edges of bamboo patches because these edges offer them more food than the interiors. The number of feeding sites and the corresponding vegetation indices (including the basal diameter of bamboo stem, height and density of bamboo or bamboo shoot; density and canopy density of trees) were compared close to and far away from the edges of bamboo patches to detect the patterns of feeding habitat selection by giant pandas. Giant pandas preferred to forage at the sites near edges rather than in the interiors of bamboo patches. Such a tendency was independent of bamboo species and individual pandas. By comparing the density, basal diameter of bamboo stem and shoot, tree density and available dry biomass of bamboo, we detected no significant differences between the edges and the interiors of bamboo patches. The possible explanations were analysed and it was deemed that the selection of food habitat near edges by the giant pandas could be attributed to the direct effects of edges, which facilitate movement of the giant pandas in the otherwise dense bamboo patches.