Environmental controls override grazing effects on plant functional traits in Tibetan rangelands

作者：Yun Jäschke, Gwendolyn Heberling, Karsten Wesche · 发表于：Functional Ecology · 年份：2019 · DOI：10.1111/1365-2435.13492 · 被引用次数：62 · 研究领域：Ecology and Vegetation Dynamics Studies、Plant and animal studies、Plant Parasitism and Resistance

Abstract Plant functional traits are key to predict community responses to abiotic and biotic disturbances. Grazing is the dominant land‐use form in drylands and alpine environments, especially in Central Asian rangelands. Here, we address grazing effects and their relative importance against environmental controls on plant traits. We sampled 14 plant functional traits, which are potentially sensitive to grazing, from 127 taxa distributed across three grassland types in Tibetan grasslands exposed to increasing levels of precipitation: steppe, steppe‐meadow and meadow. We performed principal components analysis and fourth‐corner analysis to explore the impacts of grazing and environment on multiple community‐weighted mean (CWM) traits. We also used generaliszed linear mixed models to test the effects of grazing and environment on each CWM trait, and on three dimensions of functional trait diversity, i.e. functional richness (FRic), evenness (FEve) and divergence (FDiv). In addition, we undertook a mini‐review of former studies on grazing effects on plant traits in Chinese grasslands. We found that CWM traits were mainly affected by climate and elevation rather than by grazing intensity. Only plant tissue C content was negatively affected by intensified grazing across grassland types. Plant growth form and life form were mainly influenced by elevation, while heights of canopy and inflorescence were controlled by temperature. Specific leaf area was positively correlated with pre...