How does grazing exclusion influence plant productivity and community structure in alpine grasslands of the Qinghai-Tibetan Plateau?

作者：Xiang Liu, Zhiwen Ma, Xiaotao Huang, Lanhai Li · 发表于：Global Ecology and Conservation · 年份：2020 · DOI：10.1016/j.gecco.2020.e01066 · 被引用次数：63 · 研究领域：Ecology and Vegetation Dynamics Studies、Rangeland Management and Livestock Ecology、Plant Ecology and Soil Science

Grazing exclusion by fencing is a commonly used management practice for restoring the degraded alpine grasslands on the Qinghai-Tibetan Plateau (QTP). However, there is currently no consensus on how grazing exclusion influences plant productivity and community structure in alpine grasslands in this region. Here, a meta-analysis was conducted to quantitatively assess the impacts of grazing exclusion on plant biomass (aboveground biomass, AGB; belowground biomass, BGB; and total biomass, TB) and various plant diversity indices (species richness, Shannon-Wiener diversity index, and Pielou evenness index) in alpine grasslands on the QTP. The results showed that on average, grazing exclusion significantly increased plant coverage, AGB, BGB, TB, and species richness by 34.4%, 93.1%, 58.0%, 67.4%, and 8.3%, respectively. In contrast, significant reductions in both Shannon-Wiener diversity index (−6.7%) and Pielou evenness index (−6.1%) were detected following grazing exclusion. It was observed that the effectiveness of grazing exclusion on recovering plant coverage, AGB, TB, and species richness decreased with the duration of grazing exclusion, and the effect size of plant species richness was negatively correlated to the duration of grazing exclusion. These results indicated that plant species might decrease with the duration of grazing exclusion. The increases in AGB, BGB, and TB were all significantly higher in alpine meadow than those in alpine steppe and alpine desert steppe, d...