Population and food web responses to variation in rates and timing of pulsed, cross-ecosystem resource subsidies

人口和食物网对脉冲式跨生态系统资源补贴的比率和时间变化的反应

• 批准号: RGPIN-2018-03838
• 负责人: Richardson, John
• 金额: $ 2.91万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=712390
• 关键词: Population; food; web; responses; variation

Many ecological communities receive resource inputs from adjacent ecosystems, sometimes very pulsed in time, such as leaf litter or terrestrial invertebrates falling into streams and wetlands in forests. Studies have shown that these “cross-ecosystem resource subsidies”, such as leaf litter, invertebrates, salmon, sea wrack, pollen and others, contribute in a large way to the productivity of the receiving ecosystems. However, most experiments on this topic involve binary comparisons based on augmentation or exclusion of a subsidy resource compared with an ambient reference or control. We have a limited understanding of how the quantitative effects of variation along characteristics of input rates, timing, duration and resource quality affects recipient population dynamics and productivity, community processes, and stability. In our research we have used leaf litter or terrestrial invertebrate inputs to streams as models to test the effects on receiving consumers. However, questions about consequences of quantitative gradients in input characteristics still need study in terms of population and community dynamics. Some stream predators use subsidy resources directly, and we have used cutthroat trout as a model system for understanding how inputs of terrestrial invertebrates affects their growth and reproduction. However, there are few studies of the consequences for population dynamics of those predators, including invertebrates, which do not directly use subsidies themselves, i.e. effects moderated through food webs. Food-web size structure is likely important given that predators (invertebrates and vertebrates) span several orders of magnitude in mass in food webs, and yet predators are often grouped as a single functional category. Thus, we will also test questions of size-dependent responses of consumers. Further, increases in productivity of recipient consumers have rarely been followed carefully into other parts of their food webs, which we will address. We have used field-based experimental manipulations to test the effects of input rates and quality of subsidies, and have made some progress on considering how these characteristics affect recipient populations and communities. The work proposed here will expand our understanding and predictive capability of how pulsed resource subsidies affect the productivity and stability of recipient populations and communities. Moreover, this work will serve to demonstrate the importance of protecting and managing ecosystems adjacent to aquatic environments, e.g. in forestry, agricultural and urban settings, to sustain productive and healthy freshwaters.

许多生态群落从相邻的生态系统中收到资源投入，有时会及时脉冲，例如叶子或陆生无脊椎动物落入森林中的溪流和湿地。研究表明，这些“跨生态系统资源补贴”，例如叶子，无脊椎动物，鲑鱼，海包，花粉等，对接收生态系统的生产力做出了很大的贡献。但是，与环境参考或对照相比，大多数有关此主题的实验都涉及基于增强或排除补贴资源的二进制比较。我们对输入率，时机，持续时间和资源质量的特征的变异的定量效应如何影响受体人口动态和生产力，社区过程和稳定性。 在我们的研究中，我们将叶子垃圾或陆层无脊椎动物输入用于流作为模型，以测试对接收消费者的影响。但是，关于输入特征中定量梯度后果的问题仍然需要在人群和社区动态方面进行研究。一些流捕食者直接使用补贴资源，我们使用cutthroat鳟鱼作为模型系统，以了解陆生无脊椎动物的输入如何影响其生长和繁殖。但是，很少有关于这些捕食者人群动态的后果的研究，包括无脊椎动物，这些捕食者本身并不直接使用补贴，即通过食物网的效果。鉴于食物网中质量的几个数量级，食物 - 网络大小的结构可能很重要，而食物网的质量数量数量几个数量级，而捕食者通常被分为单个功能类别。这是我们还将测试消费者大小依赖的回答问题。此外，收件人消费者的生产率提高很少被仔细遵循其食物网的其他部分，我们将解决。 我们已经使用基于现场的实验操作来测试输入率和补贴质量的影响，并在考虑这些特征如何影响受体人群和社区方面取得了一些进展。这里提出的工作将扩大我们对脉冲资源补贴如何影响接受者人群和社区的生产力和稳定性的理解和预测能力。此外，这项工作将有助于证明保护和管理与水生环境相邻的生态系统的重要性，例如在林业，农业和城市环境中，以维持生产和健康的淡水。