Experimentally disentangle the impacts of livestock and pika on the degraded Kobresia ecosystem
Assigned Session: FS 3.111: Degradation and conservation of Tibetan and Himalayan ecosystems: Challenges and pathways to resilience
Abstract ID: 3.10016 | Accepted as Poster | Requested as: Poster | TBA | TBA
Yang Siwei (1)
Niu, Yujie (2)
(1) Sichuan Academy of grassland Sciences, Cheng du
(2) Department of Disturbance Ecology, University of Bayreuth, Bayreuth
Abstract
Kobresia ecosystems are the most widespread grassland ecosystems on the Tibetan Plateau. Over the past four decades, ecological restoration strategies—such as fencing to control livestock and the eradication of burrowing rodents (e.g., plateau pika)—have been widely implemented to address the degradation of these ecosystems. These strategies are based on the assumption that Kobresia ecosystem degradation is exacerbated by burrowing rodents. However, these assumptions remain controversial due to a lack of experimental evidence. To provide a scientific basis for the sustainable use of grasslands, this study aims to disentangle the effects of yak grazing and plateau pika on vegetation and soil in degraded Kobresia ecosystems. In May 2024, we established an experiment with four treatments:
(1) both yak and pika present (+Y/+P),
(2) yak only (+Y/−P; pika excluded),
(3) pika only (−Y/+P; yak excluded), and
(4) neither yak nor pika (−Y/−P; both grazing and pika excluded),
in a degraded Kobresia ecosystem affected by overgrazing and a pika outbreak. After only one growing season of exclusion, data show that vegetation height, cover, and aboveground biomass in the yak plots were significantly lower than in plots without yak, regardless of the presence of pika. These findings suggest that plateau pika exert no significant effects on vegetation under either grazed or ungrazed conditions. We recommend reducing grazing intensity and urge the government to reconsider current pika eradication policies in the management of Kobresia ecosystems.
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