Spatial and climatic patterns of the relative abundance of poisonous vs. non-poisonous plants across the Northern Tibetan Plateau

作者：Jianshuang Wu, Pengwan Yang, Xianzhou Zhang, Zhenxi Shen, Chengqun Yu · 发表于：Environmental Monitoring and Assessment · 年份：2015 · DOI：10.1007/s10661-015-4707-z · 被引用次数：21 · 研究领域：Rangeland Management and Livestock Ecology、Ecology and Vegetation Dynamics Studies、Wildlife Ecology and Conservation

It is the most serious challenge to promote degraded grassland recovery currently facing the developing Tibetan Autonomous Region. We conducted field surveys of 75 grazing sites between 2009 and 2012 across the Northern Tibetan Plateau and described the spatial and climatic patterns of the occurrence of poisonous plants. Our results showed lower ratios of species richness (SprRatio), coverage (CovRatio), and biomass (BioRatio) of non-poisonous vs. poisonous plants in the semi-arid alpine steppe zone, where the growing season precipitation (GSP) is between 250 and 350 mm; however, this result is in contrast to the relatively wetter meadow (GSP >350 mm) and much drier desert-steppe (GSP <250 mm) communities. Results from generalized additive models (GAMs) further confirmed that precipitation is primarily responsible for the initially decreasing and then increasing tendency of compositional ratios of non-poisonous to poisonous species. The wide confidence bands at GSP <250 mm indicated that precipitation is not an effective indicator for predicting compositional changes in desert-steppe communities. When mean annual livestock grazing pressure was incorporated into the optimal GAMs, the model performance improved: the Akaike information criterion (AIC) decreased by 1.20 for SprRatio and 3.09 for BioRatio, and the deviance explained (R (2)) increased by 6.0% for SprRatio and 3.6% for BioRatio. Therefore, more detailed information on grazing disturbance (timing, frequency, and dens...