The burying and grazing effects of plateau pika on alpine grassland are small: a pilot study in a semiarid basin on the Qinghai-Tibet Plateau
- 1State Key Laboratory of Cryosphere Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, 320 Donggang West Road, Lanzhou 730000, China
- 2School of Geographic Sciences, Nantong University, 999 Tongjing Road, Nantong 226007, China
- 3University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing 100049, China
Abstract. There is considerable controversy about the effects of plateau pika (Ochotona curzoniae, hereafter pika) on alpine grassland on the Qinghai-Tibet Plateau (QTP). On the one hand, pika is considered a keystone species. On the other hand, it is being poisoned. Although significant efforts have been made to study the effects of pika at a quadrat scale ( ∼ m2), our knowledge about its distribution and effects at a larger scale is very limited. In this study, we investigated the direct effects, i.e., burying and grazing, of pika by upscaling field sampling at a quadrat scale to a plot scale ( ∼ 1000 m2) by aerial photographing. Altogether 168 plots were set on four different types of alpine grassland in a semiarid basin on the QTP. Results showed that (1) the effects of pika pile burying on the reduction of vegetation cover, biomass, soil carbon, and nitrogen were less than 10 %, which was much smaller than the effects of bald patches; and (2) pika consumed 8–21 % of annual net primary production of grassland. We concluded that the direct burying and grazing effects of pika on alpine grassland were minor in this region. The quadcopter is an efficient and economic tool for long-term repeated monitoring over large regions for further understanding the role of pika.