Staying or leaving: Triggers of emigration

分散性是生物体的一个基本特征，它影响着整个群落的稳定性和多样性，从而影响整个群落的长期存在。这一扩散过程可分为引导性迁出、迁移到其他栖息地和迁徙到新栖息地。扩散是多因的，受生物体的特性和环境因素的影响。以前的研究表明，生物密度、食物可获得性和捕食者的压力是导致迁出的典型原因。这些因素在种内和种间水平上影响生物体，而且它们彼此同时相互作用。科学上的挑战不是单独考虑影响因素的重要性，而是从相互作用的整体背景下考虑。本项目的主要目标是调查生物迁出的基本诱因。与以前的许多研究不同，这里的重点是各种因素(生物密度、食物可获得性和捕食者压力)的相互作用。此外，将首次量化这些因素对(1)单一物种和(2)物种组合以及(3)整个群落的影响。一系列标准化的实验室实验确保了高度的可比性和信息价值。本研究使用的测试生物是线虫，这是世界上最常见的后生动物。由于线虫的分布潜力、简单快速的栽培、物种特有的特性、在野外频繁和多样的出现以及它们的生态意义，最适合于该项目。实验在已适应线虫的试验容器中进行，其可用性已在先前的调查中得到证实。线虫被放置在起始室中，初始情况受到操纵(例如，高密度的食物和捕食者的存在)。随后，个人的迁徙在七天后被记录在案。三个中心工程段共730个单项试验将在两年内进行。

Dispersal is an essential trait of organisms that influences stability, diversity and thus also the long-term existence of whole communities. This process of dispersal can be divided into introductory emigration, transfer to other habitats and migration in the new habitat. Dispersal is multi-causal, influenced by the characteristics of an organism and environmental factors. Previous studies have shown, that organism density, food availability and predator pressure are typical causes of emigration. These factors influence organisms at the intra- and interspecific level and, moreover, interact simultaneously with each other. The scientific challenge is not to consider the importance of influencing factors solitary, but in the overall context of the interactions. The main goal of the presented project is to investigate basic triggers for the emigration of organisms. In contrast to many previous studies, the focus here is on the interactions of various factors (organism density, food availability and predator pressure). Furthermore, for the first time, the impact of these factors on (1) single species and (2) species combinations as well as on an (3) entire community will be quantified. A series of standardized laboratory experiments ensures a high degree of comparability and informative value.The test organisms used in this study are nematodes, the most common metazoans worldwide. Because of their distribution potential, the easy and fast cultivation, the species-specific characteristics, the frequent and diverse occurrence in the field and their ecological significance nematode are optimally suitable for the project.The experiments are performed in test vessels that have been adapted to nematodes and whose usability has been proven in preceding investigations. Nematodes are placed in a starting chamber with a manipulated initial situation (for example, high density of food and the presence of a predator). Subsequently, the migration of individuals is documented after seven days. In total, three central project sections with a total of 730 single tests will be carried out over a period of two years.