title: Grazing intensifies degradation of a Tibetan Plateau alpine meadow through plant-pest interaction.
abstract: Understanding the plant-pest interaction under warming with grazing conditions is critical to predict the response of alpine meadow to future climate change. We investigated the effects of experimental warming and grazing on the interaction between plants and the grassland caterpillar Gynaephora menyuanensis in an alpine meadow on the Tibetan Plateau in 2010 and 2011. Our results showed that grazing significantly increased nitrogen concentration in graminoids and sward openness with a lower sward height, sward coverage, and plant litter mass in the community. Grazing significantly increased G. menyuanensis body size and potential fecundity in 2010. The increases in female body size were about twofold greater than in males. In addition, grazing significantly increased G. menyuanensis density and its negative effects on aboveground biomass and graminoid coverage in 2011. We found that G. menyuanensis body size was significantly positively correlated with nitrogen concentration in graminoids but negatively correlated with plant litter mass. Even though warming did not significantly increased G. menyuanensis performance and the negative effects of G. menyuanensis on alpine meadow, the increases in G. menyuanensis growth rate and its negative effect on aboveground biomass under the warming with grazing treatment were significantly higher than those under the no warming with grazing treatment. The positive effects of grazing on G. menyuanensis performance and its damage were exacerbated by the warming treatment. Our results suggest that the fitness of G. menyuanensis would increase under future warming with grazing conditions, thereby posing a greater risk to alpine meadow and livestock production.
authors.affiliation: Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences Xining, 810008, China ; Graduate University of Chinese Academy of Sciences Beijing, 100049, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Cao
authors.affiliation: Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences Xining, 810008, China ; Chengdu Institute of Biology, Chinese Academy of Sciences Chengdu, 610041, China.
authors.forename: Xinquan
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences Beijing, 100101, China.
authors.forename: Shiping
authors.initials: S
authors.lastname: Wang
authors.affiliation: Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences Xining, 810008, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences Xining, 810008, China ; Binhai Research Institute in Tianjin Tianjin, 300457, China.
authors.forename: Jichuang
authors.initials: J
authors.lastname: Duan
authors.affiliation: Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences Xining, 810008, China.
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences Xining, 810008, China.
authors.forename: Shidong
authors.initials: S
authors.lastname: Ge
authors.affiliation: Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences Xining, 810008, China ; Graduate University of Chinese Academy of Sciences Beijing, 100049, China.
authors.forename: Xiaoxue
authors.initials: X
authors.lastname: Zhu
keywords: Alpine meadow; Gynaephora menyuanensis; Tibetan Plateau; experimental warming; grassland caterpillar; grazing; plant–pest interaction