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.

许多生态社区从邻近的生态系统获得资源投入，有时是非常及时的，例如落叶或陆地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”，如落叶、无脊椎动物、鲑鱼、海藻、花粉等，在很大程度上有助于接受补贴的生态系统的生产力。 然而，大多数关于这一主题的实验涉及基于与环境参考或控制相比增加或排除补贴资源的二元比较。我们有一个有限的了解如何变化的数量效应沿着特征的投入率，时间，持续时间和资源质量影响受援国人口动态和生产力，社区进程和稳定性。 在我们的研究中，我们使用落叶或陆生无脊椎动物输入流作为模型来测试对接收消费者的影响。 然而，数量梯度的输入特性的后果的问题仍然需要在人口和社区动态方面的研究。 一些流捕食者直接使用补贴资源，我们已经使用了割喉鳟鱼作为模型系统，了解陆地无脊椎动物的投入如何影响他们的生长和繁殖。 然而，很少有研究表明，这些捕食者，包括无脊椎动物，其本身并不直接使用补贴，即通过食物网缓和的影响。食物网的大小结构可能是重要的，因为捕食者（无脊椎动物和脊椎动物）跨越几个数量级的质量在食物网，但捕食者往往被归类为一个单一的功能类别。 因此，我们还将测试消费者对尺寸依赖性反应的问题。此外，接受者消费者生产力的提高很少被仔细跟踪到他们食物网的其他部分，我们将讨论。 我们已经使用了基于实地的实验操作，以测试投入率和质量的补贴的影响，并取得了一些进展，考虑这些特点如何影响受援人口和社区。 这里提出的工作将扩大我们的理解和预测能力脉冲资源补贴如何影响生产力和稳定的受援国人口和社区。 此外，这项工作将有助于表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，以维持富有生产力和健康的淡水。