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The impact of interacting processes on population dynamics.

相互作用过程对种群动态的影响。

基本信息

批准号：
NE/D014352/1
负责人：
Stephen Mark Redpath
金额：
$ 60.35万
依托单位：
University of Aberdeen
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2007
资助国家：
英国
起止时间：
2007 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FD014352%2F1
关键词：
impact interacting processes population dynamics.

项目摘要

For a wide range of applied (pest control, disease outbreak, harvesting strategies) and fundamental reasons (climate change) ecologists need to understand not only what determines the abundance of a species but also how abundance varies over time and why these patterns differ from one location to another. Considerable effort has been devoted to exploring this issue, especially in species with unstable dynamics but in only a few instances do we now have the insight into the major mechanisms. These studies have tended to focus attention on the role of single biotic factors, such as predation or parasitism, and some studies have also considered the interaction between a biotic process and climate. Yet we know that populations are governed by a variety of biotic processes and that these commonly interact. So, a major challenge, and the overall aim of this proposal, is to quantify the impact of interactions between biotic factors in relation to their climatic context on population dynamics. We will work on the red grouse, a species in the British uplands whose populations commonly show cyclic dynamics. There is considerable variation in grouse population dynamics between areas, with some populations not cyclic, and the cycle period of the strongly cyclic populations varying from 4 to 12 years. This study system and the variation within it provides us with an excellent opportunity to quantify the impact of interactions between biotic processes. Grouse have been well studied, so we can identify and manipulate the two dominant biotic processes: parasitism and territorial behaviour. Moreover, we also know that territorial behaviour and parasite intensity affect each other. However, we do not know how abiotic factors affect these interactions and how the interactions in turn affect individual fitness and emergent dynamics. Our specific aim is to test the hypothesis that the spatial variation we observe in the cyclic dynamics of grouse is the result of parasites and territorial behaviour interacting within a gradient of rainfall. To achieve this aim we have built on a successful team of empiricists by collaborating with two theoreticians, skilled in dynamic game theory and population modelling. With this team we will test our hypothesis through experimentation, modelling and testing predictions on long-term time series. We will conduct two experiments that will tell us a) how parasite intensity varies with territorial behaviour and vice-versa, b) how these interactions influence breeding success and survival across an environmental gradient; and c) what the transmission rate is between male and female grouse within pairs. A quantification of transmission between sexes is necessary to combine previous models and data. Given that more aggressive grouse pickup more parasites, we will use game theory to explore the implications of this interaction for how much individual males should invest in territorial behaviour. With input from the experiments and game theory, the population dynamic consequences of the strategy decisions will be investigated through population models. For grouse populations in locations with given values of rainfall the population models will predict what cyclic patterns would be expected. We will the test these predictions against the long-term time series of harvest records available from managed grouse moorlands across the country. Our findings will highlight the role played by interactions between biotic factors on population dynamics. This is an important issue, as it will help us understand how climate change and management will interact to influence abundance and dynamics. In Britain, these studies are both timely with respect to our current knowledge and the dramatic ecological changes being observed in parts of the uplands.

对于广泛的应用（害虫控制、疾病爆发、收获策略）和根本原因（气候变化），生态学家不仅需要了解决定物种丰度的因素，还需要了解丰度如何随时间变化，以及为什么这些模式因地点而异。人们付出了大量的努力来探索这个问题，特别是在动态不稳定的物种中，但我们现在只有在少数情况下才能深入了解主要机制。这些研究往往将注意力集中在单一生物因素的作用上，例如捕食或寄生，一些研究还考虑了生物过程与气候之间的相互作用。然而我们知道，种群受到多种生物过程的控制，并且这些过程通常相互作用。因此，一个主要挑战和该提案的总体目标是量化生物因素之间的相互作用及其气候背景对人口动态的影响。我们将研究红松鸡，这是英国高地的一种物种，其种群通常表现出周期性动态。不同地区松鸡种群动态差异较大，部分种群无周期性，强周期性种群的周期周期为4年至12年不等。这个研究系统及其内部的变化为我们提供了一个很好的机会来量化生物过程之间相互作用的影响。松鸡已被深入研究，因此我们可以识别和操纵两个主要的生物过程：寄生和领地行为。此外，我们还知道领地行为和寄生虫强度是相互影响的。然而，我们不知道非生物因素如何影响这些相互作用，以及这些相互作用又如何影响个体的适应性和突发动态。我们的具体目标是检验这样的假设：我们在松鸡的循环动态中观察到的空间变化是寄生虫和领地行为在降雨梯度内相互作用的结果。为了实现这一目标，我们与两位精通动态博弈论和人口建模的理论家合作，建立了一支成功的经验主义者团队。与这个团队一起，我们将通过实验、建模和测试长期时间序列的预测来检验我们的假设。我们将进行两项实验，告诉我们a）寄生虫强度如何随领地行为变化，反之亦然，b）这些相互作用如何影响跨环境梯度的繁殖成功和生存； c) 成对内雄性和雌性松鸡之间的传播率是多少。结合以前的模型和数据，有必要对两性之间的传播进行量化。鉴于更具攻击性的松鸡会感染更多的寄生虫，我们将使用博弈论来探讨这种相互作用对雄性松鸡个体应该在领地行为上投入多少的影响。根据实验和博弈论的输入，策略决策的群体动态后果将通过群体模型进行研究。对于具有给定降雨量的地点的松鸡种群，种群模型将预测预期的循环模式。我们将根据全国管理松鸡沼泽地的长期收获记录时间序列来测试这些预测。我们的研究结果将强调生物因素之间的相互作用对种群动态的作用。这是一个重要的问题，因为它将帮助我们了解气候变化和管理如何相互作用以影响丰度和动态。在英国，这些研究对于我们目前的知识和在部分高地观察到的巨大生态变化来说都是及时的。