Exploring ecological surprises by multiple stressors of aquatic food webs

探索水生食物网多重压力源带来的生态惊喜

• 批准号: 227347-2009
• 负责人: Vinebrooke, Rolf
• 金额: $ 2.7万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=497670
• 关键词: Exploring; ecological; surprises; multiple; stressors

The main goal of my research program is to discover ecological drivers of aquatic food-web responses to global change. Multiple human-related stressors that define global change often exert complex non-additive effects on food webs, which cannot therefore be easily predicted based on the sum of known effects by single stressors. Consequently, extreme climate change together with other stressors often generate alarming "ecological surprises." I have developed a conceptual model of the ecological mechanisms affecting multi-trophic responses to multiple stressors. The model is based on three operating hypotheses: 1) stressors exert more pronounced synergistic impacts on top predators than on plants because animals are less tolerant of rapid environmental change, 2) tolerant plant species more than top predators are able to readily colonize stressed ecosystems and functionally compensate for extinct species, and thus, 3) differences in tolerances among top predators, herbivores, and plants result in their interactions (e.g., predation and herbivory) being profoundly altered in stressed ecosystems. My research group tests these hypotheses by conducting experiments in naturally fishless alpine lakes of the Canadian Rockies, which are being increasingly impacted by extreme climate events, introduced invasive species, and air pollution. Therefore, these highly sensitive species-poor ecosystems are excellent venues for investigating the effects of multiple stressors on trophic complexity. We examine the responses of whole food webs, single trophic groups and their interactions by exposing them sequentially to summer heating events and other stressors using submersible greenhouse mesocosms. We also examine the importance of dispersal and colonization by tolerant species as a means of buffering alpine food webs against the impacts of rapid environmental change. I refine and upgrade my proposed model through comparison of experimental and naturally occurring food webs in alpine lakes that are exposed to the same combination of stressors. Our findings will help better explain why we should expect the unexpected from future global change.

我的研究计划的主要目标是发现水生食物网对全球变化的反应的生态驱动因素。定义全球变化的多种与人类有关的压力源往往对食物网产生复杂的非累加效应，因此，根据单一压力源的已知效应总和，无法轻易预测这种效应。因此，极端气候变化与其他压力因素一起，往往会产生令人担忧的“生态意外”。“我已经开发了一个概念模型的生态机制，影响多营养反应的多种压力。该模型基于三个经营假设：1）压力源对顶级捕食者比对植物施加更显著的协同影响，因为动物对快速环境变化的耐受性较低，2）耐受性植物物种比顶级捕食者更容易在受压力的生态系统中定居，并在功能上补偿灭绝物种，因此，3）顶级捕食者，食草动物，并且植物导致它们的相互作用（例如，捕食和食草动物）在压力生态系统中发生了深刻的变化。我的研究小组通过在加拿大落基山脉的自然无鱼高山湖泊中进行实验来测试这些假设，这些湖泊越来越受到极端气候事件，入侵物种和空气污染的影响。因此，这些高度敏感的物种贫乏的生态系统是调查多种压力对营养复杂性的影响的绝佳场所。我们研究了整个食物网，单一的营养群体和它们之间的相互作用的反应，通过暴露它们顺序夏季加热事件和其他压力源使用潜水温室中生态系统。我们还研究了宽容的物种作为缓冲高山食物网对快速环境变化的影响的一种手段的扩散和殖民化的重要性。我完善和升级我提出的模型，通过比较实验和自然发生的食物网在高山湖泊暴露于相同的压力组合。我们的研究结果将有助于更好地解释为什么我们应该对未来全球变化的意外有所期待。