Entwicklung von Bodendiasporenbanken im Laufe der Grünlandsukzession: Effekte der Korngrößenverteilung im Boden und der räumlichen Heterogenität der Samen

土壤种子库在决定植物群落的组成和动态方面起着重要作用。它们对受干扰群落的再生特别重要，例如在早期草原演替期间。为了研究演替过程中种子库的发展，人们对演替系列进行了大量的研究。然而，这些研究往往受到方法问题的困扰;它们缺乏详细的数据，并通过比较不同年龄的地点来调查时间趋势（“空间换时间替代”）。与这些研究相反，我们将使用一种实验方法，在充满消毒土壤的微观世界中引入种子混合物后检查种子库。在这里，我们将重点放在不同的土壤类型和种子特性对种子库组成和种子在土壤中的垂直分布的影响。为了更大规模地研究种子库的发展，我们还将研究五年前通过植物凋落物转移引入草地物种而恢复的草地下的种子库。对于这些草甸的初始种子库组成和植被发展的大量数据库是可用的。为了了解演替过程中种子库的形成，研究埋藏种子在土壤中的水平分布也很重要。通过对土壤种子小尺度异质性的研究，我们可以了解演替过程中地上植被物种的空间分布。重点介绍了短命模式种，我们将详细研究土壤种子库的空间格局。本研究的主要目的是分析土壤种子库的垂直和水平的发展及其对群落动态的影响，在草地演替早期的洪泛草甸群落。与许多其他草地物种建立了一个短暂的土壤种子库，洪泛草甸的特点是一个持久的种子库的物种的比例相对较高。除了新的信息组成的种子库在洪泛草甸及其与地上植被的相关性的时间变化，这项研究也是重要的评估潜在的依赖草地演替过程中的植被对土壤种子库。

Soil seed banks play an important role in determining the composition and dynamics of plant communities. They are particularly significant for the regeneration of disturbed communities e.g. during early grassland succession. To study the development of seed banks during succession numerous studies of successional series were carried out. However, these studies often suffer from methodological problems; they lack detailed data and investigate a temporal trend by comparing different aged sites (“space for time substitution”). In contrast to these studies, we will use an experimental approach that will examine the seed bank after introduction of a seed mixture in microcosms filled with sterilised soil. Here we will focus on the effects of different soil types and seed characteristics on seed bank composition and vertical distribution of seeds in the soil. To examine seed bank development on a larger scale, we will also study the seed bank beneath meadows which were restored five years ago by the introduction of grassland species through plant litter transfer. For these meadows a substantial data base about the initial seed bank composition and vegetation development is available. To understand seed bank formation during succession it is also important to study the horizontal distribution of buried seeds in the soil. With more information about small-scale heterogeneity of seeds in the soil, we may understand spatial distribution of species in the above-ground vegetation during succession. With a focus on an introduced short-lived model species we will examine in detail the spatial pattern of the soil seed bank. The main goal of this study is to analyse the vertical and horizontal development of soil seed banks and their effects on community dynamics during early grassland succession in floodmeadow communities. In contrast to many other grassland species which built up a transient soil seed bank, flood-meadows are characterised by a relatively high percentage of species with a persistent seed bank. Beside new information about temporal changes in composition of seed banks in flood-meadows and their correlation with above-ground vegetation, the study is also important for assessing the potential reliance of the vegetation on soil seed banks during grassland succession.