Diversity loss and trait dynamics in natural plankton communities

该项目的目标是评估具有共同进化历史的自然社区的特征丧失对特征动态的影响及其对消费者健康和生产力的影响。在这样一个背景下的性状多样性及其对生产者和消费者社区动态的影响，这一总体目标可以特别好地解决通过物种的具体特征（色素和脂肪酸组成）在湖泊食物网中的浮游植物-浮游动物界面。 我们拟议的工作计划旨在调查以下研究问题：是负责生物多样性的特征，生态系统功能在实验室浮游生物群落也相关的自然领域的浮游生物种群，并显示这些特征更复杂的动态“野生自然”？因此，仅从实验室研究中很难预测重要生理生态性状丧失的后果，特别是如果发生复杂的相互作用和反馈循环。因此，迫切需要调查的物种多样性操纵的演变领域的社区。我们将使用自然浮游植物群落的一系列可检验的假设（A-C）来解决这个研究问题。我们将在两种不同的损失情况下研究这些假设（稀有物种的损失，压力敏感物种的损失）和沿着营养梯度（寡养生物到富养生物）在田间和受控实验室实验中的差异。A）与营养学相关，在“野生自然”中影响浮游生物动态的动态和功能特征是例如浮游植物的分类群特异性色素组成和分类群-浮游植物群落中必需脂质（特别是脂肪酸）的特定组成。B）天然浮游植物的分类群和由此产生的功能性状多样性（色素、脂肪酸）与该群落对食草性浮游动物的营养互补性相关。C）不同的浮游动物群体（例如不同的水蚤基因型）对必需脂肪酸可用性限制的敏感性不同。因此，特征多样性（脂肪酸）的丧失会影响浮游动物之间的竞争性相互作用。这反过来又会影响浮游动物群落的遗传和/或分类组成，从而对浮游植物群落组成和相应的功能性状产生动态反馈效应。这些假设将在一个双重的方法来解决，使用实验室和现场实验。通过回答上述研究问题，我们将能够第一次估计的重要性，在自然远洋社区的特征损失，并机械地连接到生态系统功能的个人生态生理特征的动态。

The project's objective is to assess the impact of a loss of traits from natural communities with shared evolutionary history on trait dynamics and their effect on consumer fitness and productivity. In such a context of trait diversity and their impact on producer and consumer community dynamics, this general objective can be particularly well addressed through species specific traits (pigment and fatty acid composition) at the phytoplankton-zooplankton interface in lake food webs. Our proposed work programme aims to investigate the following research question: Are traits that are responsible for biodiversity - ecosystem functions in laboratory plankton communities also relevant for natural field populations of plankton and show these traits more complex dynamics in "wild nature"? Consequences of losses of important ecophysiological traits can then not easily be predicted from laboratory studies alone, in particular, if complex interactions and feed-back loops occur. Investigations of evolved field communities manipulated in species diversity are therefore urgently needed. We will address this research question with a chain of testable hypotheses (A-C) using natural phytoplankton communities. We will investigate these hypotheses at two different loss scenarios (loss of rare species, loss of stress sensitive species) and along a trophic gradient (oligotroph to eutroph) in the field and in controlled laboratory experiments.A) Ecologically relevant, dynamic and functional traits affecting plankton dynamics in "wild nature" are e.g. the taxon specific pigment composition of phytoplankton and the taxon-specific composition of essential lipids (in particular fatty acids) in the phytoplankton community.B) The taxon and thereby functional trait diversity of natural phytoplankton (pigments, fatty acids) is correlated with the nutritional complementarity of this community for herbivorous zooplankton. C) Different zooplankton groups (e.g. different Daphnia genotypes) differ in their susceptibility to limitations by the availability of essential fatty acids. A loss of trait diversity (fatty acids) can thus affect competitive interactions between zooplankton. This can in turn affect the genetic and/or taxonomic composition of the zooplankton community resulting on dynamic feedback effects on phytoplankton community composition and the corresponding functional traits. These hypotheses will be addressed in a dual approach, using laboratory and field experiments. By answering the above stated research questions, we will be able for the first time to estimate the importance of trait losses in natural pelagic communities and to link mechanistically the dynamics of individual ecophysiological traits to ecosystem functioning.