Temporal dynamics of tree diversity effects on growth, mortality and biomass production (BIOTREE project)

人们日益认识到生物多样性是生态系统的一个关键组成部分，直接影响许多生态过程和功能。生物多样性生态系统功能研究的最大部分仍然来自快速增长和小型模型系统，如草地。然而，最近科学家们开始研究在复杂的木本系统中改变树木多样性的影响。在这样做的过程中，在过去20年中建立了几个树木多样性实验，现在形成了一个全球性的实验网络。在这里，我建议分析树木的生长，死亡率和生物量生产的一些最古老的树木多样性实验（BIOTREE），位于图林根州，德国的多样性的意义。BIOTREE项目包括在三个地点进行的四个不同的实验，采用不同的设计种植了树木多样性不同的新树木。在两个实验中，建立了树种丰富度梯度。在第三个实验中，功能多样性的差异已经创建，同时保持每个小区的物种数量不变。 在第四个实验中，物种均匀度和种植密度已被操纵。总共种植了20多万棵树。我建议延长现有的时间序列的树木生长和死亡率的评估与新的测量活动16年后种植。其主要目的是调查和量化树木多样性对树木生长，死亡率和生物量生产的影响的时间尺度依赖性。此外，还将测试基于无人机的树高测量是否适用于密集的树木。该项目将提供关于树木多样性-生产力关系的第一批长期数据，从而有助于森林生物多样性-生态系统功能研究。

Biodiversity is increasingly recognized as a key component of ecosystems that directly influences many ecological processes and functions. The largest fraction of biodiversity-ecosystem functioning research still comes from fast-growing and small-statured model systems such as grasslands. However, more recently scientists have started to study the effects of changing tree diversity in complex woody systems. In doing so, several tree diversity experiments have been established within the last 20 years, forming now a global network of such experiments. Here, I propose to analyse the significance of tree diversity for growth, mortality and biomass production in some of the oldest tree diversity experiments (BIOTREE), located in Thuringia, Germany. The BIOTREE project encompasses four different experiments at three sites, where new tree stands differing in tree diversity have been planted adopting different designs. In two experiments, gradients of tree species richness have been established. In a third experiment, differences in functional diversity have been created while keeping the number of species per plot constant. In a fourth experiment, species evenness and planting density have been manipulated. In total, more than 200,000 trees have been planted. I suggest to extend existing time series of tree growth and mortality assessments with a new measurement campaign 16 years after planting. The central aim is to investigate and quantify temporal scale dependencies of tree diversity effects on tree growth, mortality and biomass production. In addition, drone-based tree height measurements will be tested for the use in dense tree stands. This project will provide first long-term data on the tree diversity-productivity relationship, thus contributing to forest biodiversity-ecosystem functioning research.