Longer growing seasons shift grassland vegetation towards more-productive species
Longer growing seasons shift grassland vegetation towards more-productive species
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DOI：
10.1038/nclimate3032
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发表时间：
2016-09-01
影响因子：
30.7
通讯作者：
Askew, A. P.
中科院分区：
文献类型：
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作者：
Fridley, Jason D.;Lynn, Josh S.;Askew, A. P.
尽管植物功能生态学的进展为预测植被对环境变化的反应提供了一个框架（1-3），但植物功能策略与温度升高之间的联系却知之甚少（3-5）。在这里，我们分析了响应的物种丰富的草地在英格兰北方20年的温度和降雨量的操纵的背景下，21个共存的物种，代表了大量的资源利用策略的功能属性。三个主要性状，包括身体大小（冠层高度），组织投资（叶建设成本），和种子大小，不同物种之间的独立变化，并反映与竞争力，耐胁迫和殖民能力的权衡。与过去的研究（5-7）不同，我们的结果揭示了功能性状与温度状况之间的强烈关联;生长季节延长的物种具有更高的冠层和更快的同化率，这是以牺牲那些高组织投资的物种为代价的。在深层土壤中，这种特征变暖的关联性高出三倍，这表明物种的变化是由竞争强烈介导的（8）。相比之下，植被变化从降雨量的操纵已与组织投资。响应变暖而向快速生长物种的功能转变可能是一个被认为是营养有限的系统中生产力边际增加的原因（9）。
Despite advances in plant functional ecology that provide a framework for predicting the responses of vegetation to environmental change(1-3), links between plant functional strategies and elevated temperatures are poorly understood(3-5). Here, we analyse the response of a species-rich grassland in northern England to two decades of temperature and rainfall manipulations in the context of the functional attributes of 21 coexisting species that represent a large array of resource-use strategies. Three principal traits, including body size (canopy height), tissue investment (leaf construction cost), and seed size, varied independently across species and reflect tradeoffs associated with competitiveness, stress tolerance, and colonization ability. Unlike past studies(5-7), our results reveal a strong association between functional traits and temperature regime; species favoured by extended growing seasons have taller canopies and faster assimilation rates, which has come at the expense of those species of high tissue investment. This trait-warming association was three times higher in deep soils, suggesting species shifts have been strongly mediated by competition(8). In contrast, vegetation shifts from rainfall manipulations have been associated only with tissue investment. Functional shifts towards faster growing species in response to warming may be responsible for a marginal increase in productivity in a system that was assumed to be nutrient-limited(9).