Trophic dynamic of terrestrial Arctic ecosystems under anthropogenic pressure

人为压力下北极陆地生态系统的营养动态

• 批准号: RGPIN-2014-06222
• 负责人: Lecomte, Nicolas
• 金额: $ 1.89万
• 依托单位: Université de Moncton
• 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=708094
• 关键词: Trophic; dynamic; terrestrial; Arctic; ecosystems

The identification of mechanisms that determine the dynamics of food webs is a key research area in ecology; it also represents a major step towards an improved understanding of the functioning and the vulnerability of ecosystems. However, those mechanisms cannot be understood without considering two major contemporary human-induced perturbations, namely climate change and human activities. Nowhere else on earth are the effects of global warming more threatening than in the Arctic, yet development and human presence is booming in this largely untouched biome. To fully understand how dynamics of food webs are affected by human-induced perturbations, it is also essential to consider that most ecosystems possess the capacity for energy exchanges with other ecosystems, e.g. food inputs resulting from human activities. A clear understanding of the roles of energy exchanges in food web dynamics is a prerequisite when assessing the extent of effects of global changes on tundra ecosystems experiencing a simultaneous decline of their key herbivores (e.g. lemmings) along with an increasing presence of alien predators (e.g. red foxes) that have the potential to support their energy needs from anthropogenic food sources. Such an ongoing transformation of tundra ecosystems raises major questions with respect to the fate of arctic predators and arctic-nesting birds, and to the overall functioning of arctic food webs subject to global disturbances. One of the greatest uncertainties in forecasting the direct and indirect effects of global environmental change on ecosystems is related to understanding how it will affect species interactions (here predator-prey interactions). The long-term objective of my research program is to investigate the role of predator-prey interactions in the dynamics of terrestrial Arctic food webs to better understand their functioning and sensitivity to anthropogenic perturbations, such as climate change and human-induced food subsidies. The proposed program will be conducted in two study systems (snow goose-arctic fox interaction and arctic predators-subsidies interactions) and addresses two short-term objectives: 1) to investigate the role of predator-prey interactions in mediating climatic impacts on arctic-nesting birds and arctic predators; and 2) to study the influence of climate and human presence on the rate and direction of changes in population dynamics and resource use of arctic top-predators. To achieve these objectives, I intend to use existing large-scale datasets on Arctic terrestrial vertebrates (geese and arctic top-predators, in particular) and to develop new field-based data acquisition strategies in the Canadian Arctic aiming at generating long-term research to monitor the survival and breeding success in key arctic species and to experimentally manipulate a key driving force in the terrestrial tundra, i.e. predation risk. My approaches will encompass capture-mark-recapture, stable isotopes, time series and path analyses, together with the regular consultation of local experts in Inuit communities. The program is both integrative and innovative. First, the work integrates trophic interactions under direct and indirect human perturbation in a single framework, strengthening our understanding of the population dynamics of migratory birds and their predators. Second, the approach uses state-of-the-art analytical and monitoring tools on wildlife species at the heart of Arctic communities' traditional life. While training several HQP and northerners in Arctic science, the scientific knowledge gained from this research program will provide a solid base for sound policy and wildlife management programs in the Arctic.

确定决定食物网动态的机制是生态学的一个关键研究领域;它也是朝着更好地了解生态系统的功能和脆弱性迈出的重要一步。然而，如果不考虑当代两大人类引起的扰动，即气候变化和人类活动，就无法理解这些机制。地球上没有其他地方比北极更受全球变暖的影响，但在这个基本未受影响的生物群落中，发展和人类的存在正在蓬勃发展。为了充分了解食物网的动态如何受到人类引起的扰动的影响，还必须考虑到大多数生态系统都具有与其他生态系统进行能量交换的能力，例如人类活动产生的食物投入。在评估全球变化对冻原生态系统的影响程度时，一个先决条件是要清楚地了解食物网动态中能量交换的作用，冻原生态系统的主要食草动物（如旅鼠）沿着越来越多的外来捕食者（如红狐），有可能支持他们的能源需求，从人为食物来源的同时下降。冻原生态系统的这种持续转变对北极捕食者和北极筑巢鸟类的命运以及受全球扰动影响的北极食物网的整体功能提出了重大问题。在预测全球环境变化对生态系统的直接和间接影响方面，最大的不确定性之一是了解它将如何影响物种之间的相互作用（这里指捕食者-被捕食者之间的相互作用）。我的研究计划的长期目标是研究捕食者-猎物相互作用在陆地北极食物网动态中的作用，以更好地了解它们的功能和对人为扰动的敏感性，如气候变化和人为引起的粮食补贴。拟议的计划将在两个研究系统中进行（雪鹅-北极狐相互作用和北极捕食者-补贴相互作用），并解决两个短期目标：1）调查捕食者-被捕食者相互作用在调节气候对北极筑巢鸟类和北极捕食者的影响中的作用; 2）研究气候和人类活动对北极顶级掠食者种群动态和资源利用变化的速度和方向的影响。为了实现这些目标，我打算利用现有的北极陆地脊椎动物（特别是鹅和北极顶级掠食者）的大规模数据集，并在加拿大北极地区开发新的基于实地的数据采集策略，旨在开展长期研究，以监测北极关键物种的生存和繁殖成功，并通过实验操纵陆地苔原的关键驱动力，即捕食风险。我的方法将包括捕获-标记-再捕获、稳定同位素、时间序列和路径分析，同时定期咨询因努伊特社区的当地专家。该计划是综合性和创新性的。首先，这项工作将直接和间接人为干扰下的营养相互作用整合在一个框架中，加强了我们对候鸟及其捕食者种群动态的理解。第二，该方法使用了最先进的分析和监测工具，对处于北极社区传统生活核心的野生动物物种进行分析和监测。在对几名HQP和北方人进行北极科学培训的同时，从这项研究计划中获得的科学知识将为北极的健全政策和野生动物管理计划提供坚实的基础。