Interference competition: consequences for individuals and populations

干扰竞争：对个人和群体的后果

• 批准号: RGPIN-2016-06656
• 负责人: Grant, James
• 金额: $ 2.7万
• 依托单位: Concordia University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=616439
• 关键词: Interference; competition; consequences; individuals; populations

Wild populations fluctuate in size over time, but typically between upper and lower limits. A fundamental goal of population ecology is to determine the factors that provide these limits. While population regulation is clear from the census of numerous populations over time, the actual mechanisms responsible for the regulation are less obvious, perhaps due to a paucity of large-scale field experiments. Salmonid populations in streams have emerged as important model systems for studying population dynamics, both for their tractability as experimental systems, and their importance to the economic and cultural lives of Canadians. Long-term observational studies suggest density-dependent population regulation in freshwater environments and density-independent regulation in marine environments. Our previous work has described how the territory size of individual juveniles in streams change in response to key environmental factors. In particular, we showed that territory size decreases towards an asymptotic minimum size with increasing population density, potentially providing the ultimate limit to the number of individuals that a stream can produce. However, there is a lack of experimental evidence to link what happens at the individual level to the dynamics at a population level. In this proposal, we take a field, experimental approach to address the gap in our understanding between the behavioural ecology of individuals and the dynamics of salmonid populations. In a series of field experiments, we will determine the relative importance of the three primary mechanisms of population regulation in stream salmonids: density-dependent mortality, emigration/dispersal, and individual growth rate. We will manipulate the density and size structure of young brook trout in small sections of streams to describe the population dynamics and infer the mechanisms of competition in replicate streams in Cape Race, Newfoundland. In collaboration with fisheries biologists with the U.S. Fish & Wildlife Service, we will manipulate the number of young Atlantic salmon that are stocked into multiple stream reaches in a Lake Champlain watershed to determine the behavioural mechanisms responsible for dispersal, and whether dispersal is density dependent or not. At our long-term field sites in New Brunswick, we will test whether adding boulders to streams is a viable long-term method for restoring habitat complexity and increasing the density of juvenile Atlantic salmon in streams. This proposal will provide fundamental insight into the population dynamics of a model vertebrate system. Our results will also have practical implications for how to manage, harvest and restore these valuable fish populations. My students will receive training in pure and applied ecology, allowing them to pursue careers in academics, fisheries biology and conservation science.

野生种群的规模随着时间的推移而波动，但通常在上限和下限之间。种群生态学的一个基本目标是确定提供这些限制的因素。虽然随着时间的推移对大量人口的普查可以清楚地看出人口调节，但负责调节的实际机制却不太明显，这可能是由于缺乏大规模的实地实验。 溪流中的鲑鱼种群已成为研究种群动态的重要模型系统，既因为它们作为实验系统的易处理性，也因为它们对加拿大人的经济和文化生活的重要性。长期观察研究表明，淡水环境中的种群调节与密度相关，而海洋环境中的种群调节与密度无关。我们之前的工作描述了溪流中个体幼体的领地大小如何随关键环境因素而变化。特别是，我们表明，随着人口密度的增加，领土面积逐渐减小到最小面积，这可能为河流可以产生的个体数量提供最终限制。然而，缺乏实验证据将个体层面发生的情况与群体层面的动态联系起来。 在本提案中，我们采用实地实验方法来解决我们在个体行为生态学和鲑鱼种群动态之间的理解差距。在一系列现场实验中，我们将确定溪流鲑鱼种群调节的三个主要机制的相对重要性：密度依赖性死亡率、迁移/扩散和个体增长率。我们将操纵小部分溪流中幼鳟鱼的密度和大小结构，以描述纽芬兰开普雷斯重复溪流中的种群动态并推断竞争机制。我们将与美国鱼类和野生动物管理局的渔业生物学家合作，控制尚普兰湖流域多个溪流中放养的年轻大西洋鲑鱼的数量，以确定导致扩散的行为机制，以及扩散是否与密度相关。在我们位于新不伦瑞克省的长期实地考察中，我们将测试在溪流中添加巨石是否是恢复栖息地复杂性和增加溪流中幼年大西洋鲑鱼密度的可行的长期方法。 该提案将为模型脊椎动物系统的种群动态提供基本的见解。我们的研究结果还将对如何管理、收获和恢复这些宝贵的鱼类种群产生实际影响。我的学生将接受纯生态学和应用生态学方面的培训，使他们能够从事学术、渔业生物学和保护科学方面的职业。