Differential effects of plant diversity on functional trait variation of grass species
Differential effects of plant diversity on functional trait variation of grass species
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DOI：
10.1093/aob/mcq220
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发表时间：
2011-01-01
期刊：
影响因子：
4.2
通讯作者：
Roscher, Christiane
中科院分区：
文献类型：
--
作者：
Gubsch, Marlen;Buchmann, Nina;Roscher, Christiane
背景与目的生物环境影响下的功能特性差异和特性调整可以反映物种间的生态位分配。在这项研究中，我们测试了作为光和氮吸收和利用指标的地上植物性状在分类上密切相关的物种(禾本科)之间的差异，以评估它们在增加植物多样性时的生态位分离潜力。方法在不同物种丰富度(从1到60)和存在特定功能群(草、豆科植物、高大草本植物和小草本植物)的实验草地(耶拿试验)中，测量了12种草本植物的性状。关键结果草种随着物种丰富度的增加而增加新梢和叶片长度，对支持组织(茎质量分数)和比叶面积的投资以及降低叶片的增量C-13值，这表明对光的获取付出了更大的努力。这些物种丰富的影响可以部分解释为豆类在更多样化的群落中存在的可能性更高。当牧草与豆科牧草同时生长时，叶片氮素浓度升高，地上部生物量S：氮素比降低，说明氮素营养得到改善。当与豆科牧草一起生长时，牧草叶片的增量N-15值降低，表明利用豆科植物来源的枯竭氮素，而随着物种丰富度的增加，增量N-15值减小，表明不同氮源的吸收发生了转移。然而，根据物种丰富度和豆科植物的存在，通过塑料调整性状来优化光和氮获取的努力，在不同草种之间存在显著差异。这可能进一步表明，在更多样化的植物群落中，草种的性状调整增加了生态位分离，但通过生态位分离实现的互补性在光照和营养获取方面可能不同。结论即使在草类等关系密切的物种之间，也采取了不同的策略来应对邻近物种。这种冗余性的缺乏反过来又可能促进互补资源的使用和共存。
Background and Aims Functional trait differences and trait adjustment in response to influences of the biotic environment could reflect niche partitioning among species. In this study, we tested how variation in above-ground plant traits, chosen as indicators for light and nitrogen acquisition and use, differs among taxonomically closely related species (Poaceae) to assess their potential for niche segregation at increasing plant diversity.Methods Traits of 12 grass species were measured in experimental grasslands (Jena Experiment) of varying species richness (from 1 to 60) and presence of particular functional groups (grasses, legumes, tall herbs and small herbs).Key Results Grass species increased shoot and leaf length, investment into supporting tissue (stem mass fraction) and specific leaf area as well as reduced foliar delta C-13 values with increasing species richness, indicating higher efforts for light acquisition. These species-richness effects could in part be explained by a higher probability of legume presence in more diverse communities. Leaf nitrogen concentrations increased and biomas s : N ratios in shoots decreased when grasses grew with legumes, indicating an improved nitrogen nutrition. Foliar delta N-15 values of grasses decreased when growing with legumes suggesting the use of depleted legume-derived N, while decreasing delta N-15 values with increasing species richness indicated a shift in the uptake of different N sources. However, efforts to optimize light and nitrogen acquisition by plastic adjustment of traits in response to species richness and legume presence, varied significantly among grass species. It was possible to show further that trait adjustment of grass species increased niche segregation in more diverse plant communities but that complementarity through niche separation may differ between light and nutrient acquisition.Conclusions The results suggest that even among closely related species such as grasses different strategies are used to cope with neighbours. This lack in redundancy in turn may facilitate complementary resource use and coexistence.