Synchrony in Metapopulations at Multiple Time-Scales: Theory, Experiments and Field Data

多个时间尺度的复合种群的同步性：理论、实验和现场数据

• 批准号: 1225529
• 负责人: Robert Desharnais
• 金额: $ 60万
• 依托单位: California State L A University Auxiliary Services Inc.
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-15 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1225529&HistoricalAwards=false
• 关键词: Synchrony; Metapopulations; Multiple; Time; Scales

This project aims to understand how and why collections of spatially distinct populations of a species (called metapopulations) display synchronous fluctuations in plant and animal numbers. Synchrony among populations has a serious implication for conservation biology. Synchrony means that metapopulations, on occasion, can be simultaneously rare which enhances the likelihood of extinction. Synchrony results from migration among populations and from environmental variation that affects multiple populations. The relative importance of these two mechanisms remains unknown. The current statistical methods of analyzing synchrony have shortcomings. The degree of synchrony between two population time series is usually measured by a single number, such as a correlation coefficient. However, the strength of synchrony between two time series can vary with the time scale on which it is examined, that is, synchrony may have frequency-specific components. To increase our understanding of metapopulation synchrony, this project will (1) analyze data from large spatio-temporal ecological databases, (2) develop new theory and statistical methods, and (3) conduct new laboratory experiments. The implications for climate change, extinction risks, and the mechanisms that drive synchrony (migration and environmental variation) will be assessed. Long spatially-extensive time series of environmental variables and population numbers will be analyzed to characterize the frequency-specific nature of synchrony. Analytical and numerical analyses of mathematical models will develop theoretical expectations for how frequency-specific environmental synchrony affects population synchrony and probabilities of metapopulation extinction. Experiments with laboratory populations of flour beetles will extend earlier studies in several ways. First, the investigators take a time-scale-specific perspective on both environmental and population synchrony. Second, they examine both equilibrium and chaotic populations. Previous theoretical work has show that these two dynamics respond differently to synchronizing processes. Third, their experiments will involve two sibling species of insects whose population dynamics are controlled by different density-dependent mechanisms: cannibalism of immature life stages and delay of metamorphosis. The former leads to rapid responses to perturbations and increases the tendency for demographic cycles whereas the latter leads to slow responses to perturbations and non-cyclic dynamics. The use of both species will allow an evaluation of the generality of the experimental results. This multidisciplinary approach will enhance our understanding of ecological synchrony and its relevance to society.This project will have important practical implications for the effects of global climate change on species extinction and will lead to more sophisticated methods for conserving threatened or endangered species whose populations have become fragmented. The research will capitalize on existing ecological databases and will generate and disseminate high quality laboratory data that can be used to further our understanding of the interactions among environmental variation, dispersal, and population dynamics. The mathematical and statistical tools developed will extend the traditional methods for examining synchrony to consider different time scales and will be applicable to data from other fields. The project will also contribute to the interdisciplinary education of undergraduates and graduate students, including underrepresented groups, and will create and distribute instructional materials to facilitate the use of the flour beetle system for training in quantitative ecology at the undergraduate and graduate levels.

该项目旨在了解一个物种（称为集合种群）的空间不同种群的集合如何以及为什么显示植物和动物数量的同步波动。种群间的同步性对保护生物学有着重要的意义。 同步性意味着集合种群有时可能同时稀少，这增加了灭绝的可能性。同步性来自种群间的迁移和影响多个种群的环境变化。这两种机制的相对重要性仍然未知。 现有的同步性统计分析方法存在不足。 两个人口时间序列之间的同步程度通常用一个数字来衡量，比如相关系数。然而，两个时间序列之间的同步强度可以随着时间尺度而变化，也就是说，同步可能具有频率特定的分量。为了加深我们对集合种群同步性的理解，该项目将（1）分析大型时空生态数据库的数据，（2）开发新的理论和统计方法，（3）进行新的实验室实验。将评估气候变化，灭绝风险和驱动同步（迁移和环境变化）的机制的影响。将分析环境变量和人口数量的长时间空间扩展时间序列，以表征同步的频率特异性。 数学模型的分析和数值分析将开发特定频率的环境同步性如何影响人口同步性和集合种群灭绝的概率的理论预期。 面粉甲虫实验室种群的实验将在几个方面扩展早期的研究。 首先，研究人员对环境和人口同步性采取了特定时间尺度的观点。其次，他们研究了均衡和混沌种群。 以前的理论工作表明，这两个动态响应不同的同步过程。 第三，他们的实验将涉及两种昆虫的兄弟物种，它们的种群动态受到不同密度依赖机制的控制：未成熟生命阶段的同类相食和变态延迟。 前者导致对扰动的快速反应，并增加人口周期的趋势，而后者导致对扰动和非周期动态的缓慢反应。 使用这两个物种将允许评估的实验结果的一般性。这一跨学科的方法将提高我们对生态同步性及其与社会的相关性的理解。该项目将对全球气候变化对物种灭绝的影响产生重要的实际影响，并将导致更复杂的方法来保护受威胁或濒危物种，这些物种的种群已经变得支离破碎。 该研究将利用现有的生态数据库，并将产生和传播高质量的实验室数据，可用于进一步了解环境变化，扩散和种群动态之间的相互作用。 开发的数学和统计工具将扩展传统的同步性检查方法，以考虑不同的时间尺度，并将适用于其他领域的数据。 该项目还将促进本科生和研究生，包括代表性不足群体的跨学科教育，并将编制和分发教学材料，以促进在本科生和研究生一级使用面粉甲虫系统进行数量生态学培训。