Plant Functional Group Composition Modifies the Effects of Precipitation Change on Grassland Ecosystem Function
Plant Functional Group Composition Modifies the Effects of Precipitation Change on Grassland Ecosystem Function
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DOI：
10.1371/journal.pone.0057027
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发表时间：
2013-02-20
期刊：
影响因子：
3.7
通讯作者：
Power, Sally A.
中科院分区：
文献类型：
--
作者：
Fry, Ellen L.;Manning, Pete;Power, Sally A.
温带草原生态系统面临着降水变化的未来，降水变化可能会通过减少土壤湿度和涝渍来改变群落组成和生态系统功能。有证据表明，功能多样化的植物群落包含更广泛的水资源利用和资源捕获策略，导致生态系统功能对降水变化的抵抗力更大。为了研究成分与降水变化之间的相互作用，我们在英格兰南部的连续草地上进行了三年的现场实验。这包括两种治疗。第一个是降水变化，模拟本世纪末的预测，包括夏季干旱阶段和冬季降雨增加。第二个是功能群识别，根据植物群落的功能特征将植物群落分为三类——广泛描述为多年生植物、丛生草和一年生植物——并在析因设计中删除这些组。定期测量与碳、氮和水循环相关的生态系统功能。官能团同一性的影响是明显的，主要趋势是在存在一系列多年生物种的控制条件下加工率较高。例如。在含有几种多年生植物的地块中，凋落物分解率显着更高，这些植物的平均叶片氮含量最高。当多年生植物物种占主导地位时，过程速率也受到降水变化处理的强烈影响，但在群落含有大量一年生物种和丛生草的情况下则不然。这种截然不同的反应可能归因于不同的生根模式（一年生植物的结构较浅，多年生植物的根较深）以及一年生植物比多年生植物更快的养分吸收。我们的结果表明，降水变化对含有一系列多年生和一年生物种的草原的关键过程速率的影响较小，并且维持关键功能群的存在应该是未来草原管理的一个重要考虑因素。
Temperate grassland ecosystems face a future of precipitation change, which can alter community composition and ecosystem functions through reduced soil moisture and waterlogging. There is evidence that functionally diverse plant communities contain a wider range of water use and resource capture strategies, resulting in greater resistance of ecosystem function to precipitation change. To investigate this interaction between composition and precipitation change we performed a field experiment for three years in successional grassland in southern England. This consisted of two treatments. The first, precipitation change, simulated end of century predictions, and consisted of a summer drought phase alongside winter rainfall addition. The second, functional group identity, divided the plant community into three groups based on their functional traits- broadly described as perennials, caespitose grasses and annuals- and removed these groups in a factorial design. Ecosystem functions related to C, N and water cycling were measured regularly. Effects of functional groupidentity were apparent, with the dominant trend being that process rates were higher under control conditions where a range of perennial species were present. E.g. litter decomposition rates were significantly higher in plots containing several perennial species, the group with the highest average leaf N content. Process rates were also very strongly affected by the precipitation change treatmentwhen perennial plant species were dominant, but not where the community contained a high abundance of annual species and caespitose grasses. This contrasting response could be attributable to differing rooting patterns (shallower structures under annual plants, and deeper roots under perennials) and faster nutrient uptake in annuals compared to perennials. Our results indicate that precipitation change will have a smaller effect on key process rates in grasslandscontaining a range of perennial and annual species, and that maintaining the presence of key functional groups should be a crucial consideration in future grassland management.