Limited evidence for spatial resource partitioning across temperate grassland biodiversity experiments
Limited evidence for spatial resource partitioning across temperate grassland biodiversity experiments
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DOI：
10.1002/ecy.2905
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发表时间：
2019-11-06
期刊：
影响因子：
4.8
通讯作者：
Weigelt, Alexandra
中科院分区：
文献类型：
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作者：
Barry, Kathryn E.;van Ruijven, Jasper;Weigelt, Alexandra
在当地，植物物种的丰富支持了许多生态系统功能。然而，推动这些往往是积极的生物多样性-生态系统功能关系的机制还没有被很好地理解。垂直资源梯度上的空间资源分配是更具生物多样性的草原生态系统功能增强的主要假设原因之一。如果物种在获取资源的地方不同，就会发生空间资源划分，而且地上和地下都可能发生这种情况。然而，关于草原空间资源划分的研究提供了不一致的证据。我们给出了来自草原物种丰富度梯度实验的21个数据集的荟萃分析结果。我们检验了这样的假设，即沿垂直资源梯度增加的空间资源分配增强了地上和地下不同草原植物群落的生态系统功能。为了验证这一假设，我们提出了三个问题。(1)物种丰富度是否促进了跨站点的生物量生产或群落资源吸收？(2)是否有资源示踪剂吸收和地上和地下生物量分配所表明的空间资源分配的证据？(3)空间资源分配的证据是否与生物量生产或群落资源吸收的增加相关？虽然植物物种丰富度促进了群落对氮、钾的吸收和地上和地下生物量的产生，但我们发现植物群落并不符合我们的空间资源划分标准，尽管它们确实比单一栽培在较高的冠层投入了显著更多的地上生物量。此外，不同研究的空间资源分配程度与生物量生产或群落资源吸收均不呈正相关。我们的结果表明，垂直资源梯度上的空间资源划分本身并不能为更多样化的温带草原上增强的生态系统功能提供一般解释。
Locally, plant species richness supports many ecosystem functions. Yet, the mechanisms driving these often-positive biodiversity-ecosystem functioning relationships are not well understood. Spatial resource partitioning across vertical resource gradients is one of the main hypothesized causes for enhanced ecosystem functioning in more biodiverse grasslands. Spatial resource partitioning occurs if species differ in where they acquire resources and can happen both above- and belowground. However, studies investigating spatial resource partitioning in grasslands provide inconsistent evidence. We present the results of a meta-analysis of 21 data sets from experimental species-richness gradients in grasslands. We test the hypothesis that increasing spatial resource partitioning along vertical resource gradients enhances ecosystem functioning in diverse grassland plant communities above- and belowground. To test this hypothesis, we asked three questions. (1) Does species richness enhance biomass production or community resource uptake across sites? (2) Is there evidence of spatial resource partitioning as indicated by resource tracer uptake and biomass allocation above- and belowground? (3) Is evidence of spatial resource partitioning correlated with increased biomass production or community resource uptake? Although plant species richness enhanced community nitrogen and potassium uptake and biomass production above- and belowground, we found that plant communities did not meet our criteria for spatial resource partitioning, though they did invest in significantly more aboveground biomass in higher canopy layers in mixture relative to monoculture. Furthermore, the extent of spatial resource partitioning across studies was not positively correlated with either biomass production or community resource uptake. Our results suggest that spatial resource partitioning across vertical resource gradients alone does not offer a general explanation for enhanced ecosystem functioning in more diverse temperate grasslands.