Dissertation Research: Egg Bank Dynamics and Daphnid Species Diversity

小行星9410966 在本提案中，PI将讨论休眠繁殖体在纽约奥奈达湖两种水蚤的长期种群和群落动态中的作用。虽然这两个物种在系统中持续了至少30年，但它们的水柱密度呈负相关。一个物种通常是丰富的，而另一个仍然在低数量。这种短暂的优势持续数月或数年，并已被归因于竞争和捕食的结合。这种重复出现的模式提出了两个问题：（1）每个物种如何能够长期存在，（2）如果存在竞争，为什么两个物种都存在于系统中？ 这两个物种产生滞育卵，这些卵在湖泊沉积物中保持活力可能很长一段时间。通过使用Chesson和Warner（1981）首次提出的理论模型，研究人员将检验这一假设，即储存在这些休眠卵中的生殖潜力不仅允许每个物种在这个系统中持续存在，而且还允许两个潜在竞争物种长期共存。为此，研究人员将首先独立考虑每个物种的卵子库动态。然后，他们将检验这两个物种之间的负相关性是竞争的结果的假设。最后，他们将研究休眠卵对两个物种长期相互作用的作用。 本论文的研究项目将提供第一个详细的调查替代机制的竞争物种在水生系统中共存。大多数研究集中在竞争或捕食，但繁殖体的存储是一个被忽视的现象，这可能是一个重要的关键，以了解因素，保持在水生和陆生系统的生物多样性。

9410966 Hairston In this proposal the PI's will address the role of dormant propagules in long-term population and community dynamics of two Daphnia species in Oneida Lake, New York. Although both species have persisted in the system for at least 30 years, their water-column densities are negatively correlated. One species is typically abundance while the other remains in low numbers. This transient dominance lasts for months or years, and has been attributed to a combination of competition and predation. This recurring pattern raises two questions: (1) how is each species able to persist over the long-term, and (2) if there is competition, why are both species present in the system? Both species produce diapausing eggs which remain viable in the lake sediments for a potentially long time period. By using theoretical models first proposed by Chesson and Warner (1981), the investigators will examine the hypothesis that the reproductive potential stored in these dormant eggs not only allows each species to persist in this system, but also enables long-term coexistence of two potentially competing species. To do this, the investigators will first consider the egg bank dynamics of each species independently. They will then test the hypothesis that the negative correlation between these two species is the result of competition.. Lastly, they will examine the role of the dormant eggs on the long-term interactions of the two species. %%% This dissertation research project will provide the first detailed investigation of an alternative mechanism for the coexistence of competing species in aquatic systems. Most studies focus on competition or predation, but the storage of propagules is a much neglected phenomenon which may be an important key to understanding factors that maintain biodiversity in aquatic and terrestrial systems.