藏狐的食物组成及其季节差异

The Tibetan fox (Vulpes ferrilata) is a crucial predator in the food chain in the stepper area of the Tibetan Plateau. Studies about its diet have important theoretical significance to understand its relationships with prey species, ecological adaptation strategies, and the transmission mechanism of parasitic zoonosis mediated by the food chain. In this study, 30 and 28 fecal samples of Tibetan foxes were collected from Shiqu County, Sichuan Province, during the warm season (July and August) and cold season (November) in 2019, respectively. Meta-barcode sequencing and microscopic observation were performed to analyze the dietary composition of the Tibetan fox and its seasonal differences. Results showed that the Tibetan fox mainly fed on pikas, rodents, birds, ungulates, fishes, and also insects and plants. Pikas represented by the plateau pika (Ochotona curzoniae) and the Phasianidae birds had the highest detection rates in the feces of the Tibetan fox, representing thus its main prey. Their detected rates in fecal samples did not change significantly between the cold and warm seasons. The Chi-square test showed that the frequency of Procypris (Cypriniformes: Cyprinidae) and insects in the fecal samples of Tibetan foxes in the warm season were significantly higher than that in the cold season. The α diversity and evenness of food composition in the feces of Tibetan foxes in the cold season were higher than that in the warm season, but there was no significant difference. Linear discriminant analysis effect size revealed that DNA reads of Procypris spp. in the fecal samples of the Tibetan fox in the warm season were significantly higher than that in the cold season. The principal coordinate analysis showed that food items and their sequence abundance in various fecal samples of warm season were more similar than those in samples of cold season. These results indicated that Tibetan foxes tend to prey on prevailing prey species in the warm season when food resources are more abundant, while in the the cold season, when prey resources are relatively scarcer, they increase the width of feeding niche to obtain more edible food items. This study provided fundamental information about the feeding ecology of the Tibetan fox, and its significance in the conservation and prevention of zoonotic diseases transmitted along the food chain was discussed.