Dissertation Research: Egg Bank Dynamics and Daphnid Species Diversity

9410966 Hairston在这项建议中，PI将讨论休眠繁殖在纽约Oneida Lake的两个水蚤物种的长期种群和群落动态中的作用。尽管这两个物种在该系统中至少存在了30年，但它们的水柱密度是负相关的。一个物种通常数量较多，而另一个物种数量较少。这种短暂的统治持续了几个月或几年，并被归因于竞争和捕食的结合。这种反复出现的模式提出了两个问题：(1)每个物种如何能够长期生存，以及(2)如果存在竞争，为什么两个物种都存在于系统中？这两个物种都会产生滞育卵，这些卵可能会在很长一段时间内在湖泊沉积物中存活。通过使用Chesson和Warner(1981)首次提出的理论模型，研究人员将检验这样一个假设，即这些休眠卵子中存储的生殖潜力不仅允许每个物种在这个系统中生存，而且还使两个潜在竞争物种能够长期共存。要做到这一点，研究人员将首先独立考虑每个物种的卵库动态。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，他们将研究休眠卵子对这两个物种长期互动的作用。这篇论文的研究项目将为水生系统中竞争物种的共存提供第一个详细的替代机制。大多数研究集中在竞争或捕食，但繁殖的储存是一个被忽视的现象，这可能是理解水生和陆地系统中维持生物多样性的因素的重要关键。

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.