Resource fluctuations and niche separation in plant communities: Can land-use effects on soil moisture explain observed patterns in plant diversity?

Silvertown等人提出了草原系统中植物多样性的假设。(1999自然)分别与植物物种对干旱和饱和水分土壤的耐受性有关。他们认为，耐旱物种对淹水土壤特别敏感，反之亦然，这就产生了一种旱涝权衡，这解释了植物的多样性。这一水生态假说还没有得到独立或实验的检验。在这里，我们建议使用在生物多样性探索中收集的独特数据来检验水生态假说。此外，我们建议调查土地利用和土壤类型对水文条件的影响，并测试对水文影响的替代解释(特别是与土壤化学有关的解释)。此外，我们还建议在中观生态系统中进行两个操作实验，以检验土壤水分波动与植物多样性之间的因果联系，并弄清养分有效性和土壤水分的贡献。最后，我们提出了一项初步研究，将水生态假说转移到森林下层。在这里，对遮荫的适应可能与对光斑的生理耐受性进行权衡，因此，森林地面植物多样性可以类似地通过对波动的资源条件的不同适应来解释。

Plant diversity in grassland systems has been hypothesised Silvertown et al. (1999 Nature) to be related to the plant species' tolerance to drought and water saturated soil, respectively. They argue that drought-tolerant species are particularly sensitive to water-logged soils and vice versa, yielding a drought-water logging-trade off that explains plant diversity. This hydro-ecological hypothesis has as such not been tested independently or experimentally. Here, we propose to use the unique data collected within the Biodiversity Exploratories to test the hydro-ecological hypothesis. Furthermore, we propose to investigate the effect of land use and soil type on hydrological conditions and to test alternative explanations for the hydrological effect (particularly related to soil chemistry). Also, we propose to carry out two manipulative experiments in mesocosms to test the causal link between fluctuating soil moisture and plant diversity, and to disentangle the contribution of nutrient availability and soil moisture. Finally, we propose a pilot study to transfer the hydro-ecological hypothesis to the forest understorey. Here adaptation to shade may trade-off against physiological tolerance of light spots and thus forest floor plant diversity may be similarly explained by differential adaptation to fluctuating resource conditions.