Influence of plant water relation on ecosystem function and quantification of soil water fluxes for nutrient and carbon budgets

这项研究的目标是了解生物多样性在草原群落内水关系中的作用，这是由DFG研究小组在耶拿实验中建立的。我们尤其想要调查生物多样性是否有助于有效利用土壤水分，从而提高生态系统生产力。此外，我们将研究当夏季水资源变得有限时，特定植物群落获得水的能力。我们假设，在不同的社区中，深植植物的发生率高于不太多样化的社区，并且在不同的社区中，使用更深的水资源将缓解水压力。此外，关于垂直水流的结果将有助于养分和碳收支的计算。为了验证我们的假设，我们建议从高空间和时间分辨率的土壤水分数据计算蒸腾和水分吸收剖面。考虑到土壤水分测量设备的成本和数据负载，我们将只测量选定的地块和有限的多样性梯度(2，4，16种)。这些测量将与反向水文模型相结合，后者是耶拿实验中专门用于量化地下通量和蒸腾作用的装置。该项目将有助于理解生物多样性在水资源利用效率和资源分配方面的作用。特别是，该项目阐明了这样一个问题，即什么是蒸腾作用随生物多样性增加而增加的驱动因素。

The goal of this research is to understand the role of biodiversity for water relations within grassland communities established in the Jena Experiment by the DFG Research Group. In particular we want to investigate if biodiversity contributes to efficient soil water use, and hence higher ecosystem productivity. Furthermore, we will study the capability of a given plant community to gain access to water, when water becomes limiting in summer. We hypothesize that the occurrence of deep rooted plants is higher in diverse communities than in less diverse ones, and that in diverse communities the use of deeper water resources will alleviate water stress. Furthermore the results concerning vertical water flow will be useful for the calculation of nutrient and carbon budgets.To test our hypothesis we propose to calculate transpiration and water uptake profiles from soil moisture data in high spatial and temporal resolution. With the cost of equipment for the soil moisture measurements and the data load in mind, we will only instrument selected plots and a limited diversity gradient (2, 4, 16 species). The measurements will be combined with inverse hydrological modelling, a setup that is dedicated particularly for quantification of subsurface fluxes and transpiration at the Jena Experiment.This project will contribute to understanding the role of biodiversity on efficiency of water use and resource partitioning. In particular, this project sheds light on the question, what are the driving factors for the perceived increase in transpiration with increase in biodiversity.