气候水分可获得性是热带森林大尺度海拔梯度上生物属性的主要限制因素。
Climatic water availability is the main limiting factor of biotic attributes across large-scale elevational gradients in tropical forests.
机构信息
Spatial Ecology Lab, School of Life Sciences, South China Normal University, Guangzhou 510631, Guangdong, China.
Guangzhou Qimao Ecological Technology Co., Ltd., Guangzhou 510631, Guangdong, China.
出版信息
Sci Total Environ. 2019 Jan 10;647:1211-1221. doi: 10.1016/j.scitotenv.2018.08.072. Epub 2018 Aug 6.
Climatic water availability is a key spatial driver of species distribution patterns in natural forests. Yet, we do not fully understand the importance of climatic water availability relative to temperature, and climate relative to edaphic factors for multiple biotic attributes across large-scale elevational gradients in natural forests. Here, we modelled multiple abiotic factors (elevation, climate, and edaphic factors) with each of the taxonomic-related (Shannon's species diversity, species richness, species evenness, and Simpson's dominance) and tree size or biomass-related (individual tree size variation, functional dominance and divergence, and aboveground biomass) biotic attributes through boosted regression trees (BRT) models, using biophysical data from 247,691 trees across 907 plots in tropical forests in Hainan Island of Southern China. The tested multiple abiotic factors explained simultaneously 43, 50, 36, 45, 37, 50, 17 and 46%, respectively, of the variations in Shannon's species diversity, species richness, species evenness, Simpson's dominance, individual tree size variation, functional dominance, functional divergence and aboveground biomass. After the large influences of elevation (i.e. 30.43 to 62.83%), climatic water availability accounted for most (i.e. 15.52 to 25.30%) of the variations in all biotic attributes. Beside the increasing trend with elevational gradients, taxonomic diversity increased strongly with climatic water availability whereas tree size or biomass-related biotic attributes showed strong decreasing and increasing trends. Tree size or biomass-related rather than taxonomic-related biotic attributes also decreased apparently with mean annual temperature. Most of the biotic attributes monotonically increased with soil fertility but decreased with soil pH, whereas soil textural properties had mostly negligible influences. This study strongly reveals that future climate change (i.e. a decrease in climatic water availability with an increase in mean annual temperature) is thus likely to have a substantial influence on the biotic attributes in the studied tropical forests across large-scale elevational gradients.
气候水分可用性是自然森林物种分布格局的关键空间驱动因素。然而，我们并不完全了解气候水分可用性相对于温度、气候相对于土壤因子对于自然森林大尺度海拔梯度上多种生物属性的重要性。在这里，我们通过 boosted regression trees (BRT) 模型，用 907 个样地中 247691 棵树的生物物理数据，对多个非生物因素（海拔、气候和土壤因子）与每个与分类学相关的（香农物种多样性、物种丰富度、物种均匀度和辛普森优势度）和树木大小或生物量相关的（个体树木大小变化、功能优势和发散以及地上生物量）生物属性进行建模。测试的多个非生物因素分别解释了香农物种多样性、物种丰富度、物种均匀度、辛普森优势度、个体树木大小变化、功能优势、功能发散和地上生物量变化的 43%、50%、36%、45%、37%、50%、17%和 46%。在海拔（即 30.43%至 62.83%）的巨大影响之后，气候水分可用性占所有生物属性变化的大部分（即 15.52%至 25.30%）。除了随着海拔梯度的增加趋势外，分类多样性随着气候水分可用性的增加而强烈增加，而树木大小或生物量相关的生物属性则表现出强烈的减少和增加趋势。树木大小或生物量相关的生物属性而不是分类学相关的生物属性也随着年平均温度的升高而明显减少。大多数生物属性与土壤肥力呈单调递增关系，但随土壤 pH 值降低而降低，而土壤质地特性的影响大多可忽略不计。本研究强烈表明，未来气候变化（即气候水分可用性减少和年平均温度升高）很可能对大尺度海拔梯度上研究热带森林的生物属性产生重大影响。
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