Dissertation Research: Causes of Complex Dynamics in Cardamine Pensylvanica Populations

9321790安东诺维奇这个项目是对杂草植物碎米甘草种群动态控制机制的研究。在早期的一项研究中，这些植物的实验种群在15代的时间里表现出复杂的数字动态，种群在三到四代中从低密度循环到高密度。尽管依赖于密度的种群增长的简单模型预测了振荡动态是可能的，但这些模型预测了稳定的(非周期)动态，当应用于我们的实验种群时。这个项目将调查导致模型预测和观测到的动力学之间差异的因素。从这一点上，研究人员推断，类似的机制可能会在什么时候驱动自然种群中的复杂动态。自然界中复杂动力学的意义是双重的。首先，如果这些动态是确定性种群调控的产物(而不是资源可获得性的随机波动)，那么解释自然的复杂性的尝试应该侧重于理解驱动这些过程的反馈机制。其次，由于人口的随机性，大小高度可变的种群容易灭绝，并且由于随机遗传变化的概率增加，可能无法适应不断变化的环境。因此，对种群动态的理解对于解释基本的生态学研究以及环境管理至关重要。T vV！！！F v v(Times New Roman符号&Amp；Arial L“h*ex*ex*e 9 7水晶黑剪力水晶黑剪力

9321790 Antonovics This project is an investigation of the mechanisms governing population dynamics in Cardamine pennsylvanica, a weedy plant. In an earlier study, experimental populations of these plants displayed complex numerical dynamics over fifteen generations, with populations cycling from low to high density in three to four generations. Although simple models of density-dependent population growth predict that the oscillatory dynamics are possible, these models predicted stable (non-cyclic) dynamics when applied to our experimental populations. This project will investigate what factors responsible for the discrepancy between the model predictions and the observed dynamics. From this, the investigators extrapolate to when similar mechanisms might drive complex dynamics in natural populations. The significance of complex dynamics in nature is twofold. First, if these dynamics are the product of deterministic population regulation (as opposed to stochastic fluctuations in resource availability), then attempts to interpret the complexity of nature should focus on understanding the feedback mechanisms that drive these processes. Second, populations that are highly variable in size are prone to extinction due to demographic stochasticity, and may be unable to adapt to a changing environment due to increased probability of random genetic change. Thus, an understanding of population dynamics is crucial to interpreting basic ecological studies, as well as to environmental management. t v v ! ! ! F v v ( Times New Roman Symbol & Arial l " h * eX* eX* e 9 7 Crystal Blackshear Crystal Blackshear