Dissertation Research: The Importance of Local Density and Relative Frequency for Plant Population Dynamics

最近有几个关于一年生植物之间竞争的理论和经验研究。尽管有这些努力，许多经验学家和理论家一致认为，对于空间异质性对植物之间竞争相互作用的影响，人们知之甚少。这是令人不安的，因为植物分布的斑块性质，以及斑块和扩散的能力，显着改变简单离散模型中的竞争关系。缺乏：1)操纵种间和种内竞争对手空间分布的实验；2)研究扩散(改变这些分布)的后果的实验；以及3)研究具有非随机空间格局的物种之间竞争相互作用的理论框架。本项目将研究空间分布和种子传播如何影响早熟禾和千里光竞争种群的动态。将进行一系列在受控条件下操纵空间分布的单代竞争实验。此外，还将通过进行实地实验来纳入扩散的影响，在这些实验中，空间分布和扩散将在许多世代中进行微型化。与这些实验并行的是一个模型，以探索关于扩散和空间模式如何相互作用来确定植物种群动态的更一般问题。

There have been several recent theoretical and empirical studies of competition between annual plants. Despite these efforts, many empiricists and theoreticians agree that there is little understanding of the impact of spatial heterogeneity on competitive interactions between plants. This is disturbing given the patchy nature of plant distributions and the ability of patchiness and dispersal to markedly alter competitive relationships in simple discrete models. The following are lacking: 1) experiments in which the spatial distrubutions of inter- and intraspecific competitors are manipulated; 2) experiments in which the consequences of dispersal (which alters these distributions) are investigated; and, 3) a theoretical framework for investigating competitive interactions between species with nonrandom spatial patterns. This project will investigate how spatial distributions and seed dispersal influence the dynamics of competing populations of Poa annua and Senecia vulgaris. A series of single generation competition experiments in which spatial distribution is manipulated under controlled conditions will be performed. Also the effects of dispersal will be incorporated by performing field experiments in which spatial distributions and dispersal are minipulated over many generations. Parallel with these experiments a model to explore more general questions about how dispersal and spatial patterns interact to determine plant population dynamics.