The impact of interacting processes on population dynamics.

相互作用过程对种群动态的影响。

• 批准号: NE/D013763/1
• 负责人: Stephen Mark Redpath
• 金额: $ 2.49万
• 依托单位: UNIVERSITY OF EXETER
• 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%2FD013763%2F1
• 关键词: impact; interacting; processes; population; dynamics.

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是什么决定了物种的丰富度，而且还要了解丰富度如何随时间变化，以及为什么这些模式从一个地方到另一个地方不同。相当大的努力一直致力于探索这个问题，特别是在物种与不稳定的动力学，但在少数情况下，我们现在有洞察力的主要机制。这些研究往往侧重于单一生物因素的作用，如捕食或寄生，有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，人口是由各种生物过程，这些通常相互作用。因此，一个主要的挑战，也是这一建议的总体目标，是量化生物因素之间的相互作用与其气候背景对人口动态的影响。我们将研究红松鸡，这是英国高地的一个物种，其种群通常表现出周期性动态。有相当大的变化，松鸡种群动态的地区之间，与一些人口不循环，和强烈的循环人口的周期从4年到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。松鸡已经得到了很好的研究，所以我们可以识别和操纵两个主要的生物过程：寄生和领土行为。此外，我们还知道，领土行为和寄生虫密度相互影响。然而，我们不知道非生物因素如何影响这些相互作用，以及这些相互作用如何反过来影响个体适应性和涌现动力学。我们的具体目标是测试的假设，我们观察到的松鸡的周期性动态的空间变化是寄生虫和领土的行为在降雨梯度内相互作用的结果。为了实现这一目标，我们已经建立了一个成功的团队，通过与两位理论家合作，熟练的动态博弈论和人口建模。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测试我们的假设。我们将进行两个实验，将告诉我们a）寄生虫强度如何随领土行为而变化，反之亦然，B）这些相互作用如何影响繁殖成功和环境梯度的生存;以及c）配对内雄性和雌性松鸡之间的传播率。对两性之间的传播进行量化是必要的，以便将联合收割机以前的模型和数据结合起来。鉴于更积极的松鸡拿起更多的寄生虫，我们将使用博弈论来探讨这种相互作用的影响有多少男性应该投资于领土行为。从实验和博弈论的输入，人口动态后果的战略决策将通过人口模型进行调查。对于松鸡种群的位置与给定值的降雨量的人口模型将预测什么样的循环模式将被期望。我们将测试这些预测对长期的时间序列的收获记录，从管理松鸡高沼地在全国各地。我们的研究结果将突出生物因素之间的相互作用对种群动态所起的作用。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将如何相互作用，影响丰度和动态。在英国，这些研究与我们目前的知识和在部分高地观察到的戏剧性生态变化都是及时的。