The influence of environmental changes and individual trait variability (phenotypic plasticity) on biodiversity and ecosystem stability

多样性是对环境变化作出适应性反应的一个主要先决条件。各级生物多样性（遗传、物种、相互作用）对生态系统的功能和稳定至关重要，因为较高的生物多样性意味着冗余，而冗余可以稳定生态系统，因为灭绝的物种/基因型可以被取代。此外，个体性状变异和/或表型可塑性的存在可以稳定种群波动，从而防止灭绝。然而，近年来，生物多样性正在迅速下降，而环境干扰和大规模变化的频率和严重性正在增加，因此，我们感兴趣的是个体性状变异的存在对种群的遗传多样性和捕食者-猎物相互作用的影响，以及这可能如何影响生态系统的功能和稳定性。两个假设将被考虑：（一）表型可塑性（性状变异）可能会增加生态系统的生物多样性，因为它允许更好的生态位利用。(II)表型可塑性（性状变异）可能会降低生物多样性，因为它使塑料生物体能够利用几个小生境，而不是允许不同基因型的专业化。 此外，我们将通过测试环境（非生物）胁迫如何影响生态系统的稳定性来挑战这一系统。我们将使用捕食者-被捕食者系统模型蚤状水蚤（Daphnia pulex）及其捕食者Chaoborus幼虫进行两方面的研究：1）将建立围隔实验，测试胁迫（捕食、高温和升高的CO2水平）对人工水蚤种群遗传多样性的影响。水蚤种群将由10个不同的克隆组成，它们对捕食的表型反应具有不同的反应规范。水蚤种群将暴露于一个生物压力源（无脊椎动物捕食）和两个非生物压力源，人为干扰的直接影响（高温和CO2水平升高）。我们将监测被捕食物种的克隆多样性以及捕食物种（Chaoborus幼虫）的表现。2)一个建模方法将为我们提供预测反馈回路猎物的基因型多样性和表型/基因型的相互作用和捕食者和猎物的生存能力在不同的环境条件下。通过这种综合方法，我们将更深入地了解个体性状变异和表型可塑性对种群克隆多样性的影响，以及克隆多样性如何影响生态系统的功能和稳定性的估计。

Diversity is a major precondition for the adaptive reaction to environmental change. Biodiversity at all levels (genetic, species, interactions) is crucial for ecosystem function and stability as higher biodiversity means redundancy which stabilizes ecosystems because extinct species/genotypes can be replaced. In addition, the presence of individual trait variation and/or phenotypic plasticity can stabilize population fluctuations and thereby prevent extinction. Recently however, biodiversity is declining at a rapid rate while environmental disturbances and large scale changes are increasing in frequency and severity.We are therefore interested in what influence the presence of individual trait variation has on the genetic diversity of a population and a predator-prey interaction and how this might influence ecosystem function and stability. Two hypotheses will be considered: (I) Phenotypic plasticity (trait variation) might increase the biodiversity of ecosystems because it allows for a better niche use.(II) Phenotypic plasticity (trait variation) might decrease biodiversity because it enables the plastic organism to exploit several niches rather than allowing a specialization of different genotypes. In addition, we will challenge this system by testing how environmental (abiotic) stress influences ecosystem stability.We will use the model predator-prey system Daphnia pulex and its predator Chaoborus larvae in a two-fold approach: 1) Mesocosm experiments will be set up that will test the influence of stressors (predation, high temperature and elevated levels of CO2) on the genetic diversity of an artificial Daphnia population. The Daphnia population will consist of 10 different clones with different reaction norms in their phenotypic response to predation. Daphnia populations will be exposed to one biotic stressor (invertebrate predation) and two abiotic stressors that are direct effects of anthropogenic disturbances (high temperature and elevated levels of CO2). We will monitor the clonal diversity of the prey species as well as the performance of the predator species (Chaoborus larvae). 2) A modeling approach will provide us with predictions about feedback loops on prey genotypic diversity and phenotype/genotype interaction and predator and prey survival capacities under different environmental conditions. With this integrative approach we will get a deeper insight into the effect of individual trait variation and phenotypic plasticity on the clonal diversity of populations as well as an estimate of how clonal diversity influences an ecosystem’s function and stability.