Grazing pressure index considering both wildlife and livestock in Three-River Headwaters, Qinghai-Tibetan Plateau

Grassland is not only the natural habitats for the survival of wild animals, but also the material guarantees for livestock husbandry. However, the previous studies on grassland carrying capacity are mostly only considering livestock but wild herbivores were ignored. In this study, the population of large wild herbivores, Tibetan wild ass, Tibetan gazelle and Tibetan antelope, and livestock were surveyed, and the grassland forage yield was estimated by a remote sensing-process coupled model in Qumahe Township in Three-River Headwaters, Qinghai -Tibetan in 2020. The actual carrying capacity (AC) was calculated from the both wildlife and livestock and the theoretical carrying capacity (TC) in the term on edible herbage and crude protein was estimated. Grazing pressure index was measured by the ratio of AC to TC in this region. The results showed the AC was contributed by about 20,700 standard sheep units (SHU) from wild large herbivores, and 256,500 SHU from the livestock. The theoretical carrying capacity of edible herbage, which is 274,800 SHU, was lower than the theoretical carrying capacity of crude protein in the region. If only considering livestock, the grazing capacity pressure index is 0.93, but the index will be 1.01 if the both wildlife and livestock were considered, and wildlife contributes 7.5% to the grazing pressure. This study suggested the wildlife population should be calculated in grassland ecological carrying capacity estimation though domestic livestock contributed much more to grazing pressure than wild herbivores. The new indicator would be useful in grassland management to maintain ecosystem and biodiversity balance, and society-economy sustainability.

Automated summary

Grassland is not only crucial for the survival of wild animals and livestock husbandry, but previous studies often neglected the impact of wild herbivores. This study examined the population of wild herbivores and livestock in a specific region and estimated the grassland forage yield. The results revealed that considering both wildlife and livestock is necessary for accurately assessing the carrying capacity and grazing pressure of grassland ecosystems.