摘要
Environmental and Geo-spatial factors have long been considered as crucial determinants of species composition and distributions. However,quantifying the relative contributions of these factors for the alpine ecosystems is lacking. The Tibetan Plateau has a unique ecological environment and vegetation types. Our objectives are to quantify the spatial distributions of plant communities on the Northern Tibetan Alpine grasslands and to explore the relationships between vegetation composition,Geo-spatial factors and environmental factors. We established 63 field plots along a 1200-km gradient on the Northern Tibetan Plateau Alpine Grassland and employed the two-way indicator species analysis（TWINSPAN） and the detrended canonical correspondence analysis（DCCA）. Fourteen communities of alpine grassland were identifiable along the transect and consisted of three vegetation types： Alpine meadow,Alpine steppe,and desert steppe. Vegetation composition and spatial distribution appeared to be largely determined by mean annual precipitation and less influenced by temperature. A large fraction（73.5%） of the variation in vegetation distribution was explained by environmental variables along this transect,somewhat less by Geo-spatial factors（56.3%）. The environmental and Geo-spatial factors explained 29.6% and 12.3% of the total variation,respectively,while their interaction explained 43.9%. Our findings provide strong empirical evidence for explaining biological and environmental synergetic relationships in Northern Tibet.
环境和空间因素长期以来被视为决定物种组成和分布的关键因素。然而,这些因素对高原植被的影响研究较少。青藏高原拥有一个独特的生态系统和全球环境梯度极端值。我们的目标是量化藏北高寒草地群落的空间分布,揭示植被的物种组成、空间因素和环境因素。在藏北高寒草地分布区,我们沿着1200公里长的梯度建立了63个采样点,采用双向指示种分析(TWINSPAN)和去趋势典范对应分析(DCCA)。调查发现沿横断面可识别的三种类型(高山草甸,高山草原,沙漠草原)中有14个高寒草地种群。分析发现高寒草地的植被组成和空间分布主要由年平均降雨量影响,受温度影响较小。沿着该断面,73.5%植被分布的变化能够被环境变量解释,56.3%被空间因素解释。环境和空间因素分别解释了总变异的29.6%和12.3%,而他们交互作用解释了43.9%。我们的研究结果为藏北高寒草地的生物和环境保护提供强有力的实证依据。
基金
National Key Technology Research and Development Program of China(2016YFC0501802,2017YFA0604802)
National Natural Science Foundation of China(41571195,41501103)
Youth Innovation Team Project of Key Laboratory of Ecosystem Network Observation and Modeling(LENOM2016Q0002)
