Species interactions, environmental variation and the balance of production and consumption in marine benthic communities

海洋底栖群落的物种相互作用、环境变化以及生产和消费的平衡

• 批准号: 170178-2009
• 负责人: Johnson, Ladd
• 金额: $ 2.11万
• 依托单位: Université Laval
• 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=593550
• 关键词: Species; interactions; environmental; variation; balance

Variation in interactions between trophic levels can determine whether productive or consumptive processes dominate community structure (ie, "bottom-up" vs. "top-down" control), and thus it is imperative that we understand which mechanisms modulate key species interactions and how they operate. Here I propose to examine the interaction between benthic algae and their invertebrate herbivores in two marine communities that, by the nature of their low diversity, provide a relative simple system in which to address these complex questions. The general approach is to examine variation in production and consumption along environment gradients to identify where transitions between production-dominated and consumption-dominated conditions occur, and then conduct additional observations and experiments to determine how variation in abiotic factors can shift the balance toward one community state or the other. This approach will first be developed in an intertidal system where filamentous green algae can form extensive algal mats when not controlled by herbivorous snails, and then extended to a subtidal community where consumption by urchins can create barren grounds that lack conspicuous kelp. In both systems we will focus on how variability in contrasting abiotic factors (nutrients and water motion) can permit early vulnerable stages to escape control by consumers. The results will not only contribute to general ecological theory, but will be critical for understanding the functioning of coastal ecosystems as well as addressing applied problems (eg, eutrophication).

营养水平之间相互作用的变化可以决定是生产过程还是消费过程主导了群落结构（即“自下而上”vs“自下而上”）。“自上而下”控制)，因此我们必须了解哪些机制调节了关键的物种相互作用以及它们是如何运作的。在这里，我建议研究两个海洋群落中底栖藻类和它们的无脊椎食草动物之间的相互作用，由于它们的低多样性的本质，提供了一个相对简单的系统来解决这些复杂的问题。一般的方法是沿着环境梯度检查生产和消费的变化，以确定生产主导和消费主导之间的过渡发生在哪里，然后进行额外的观察和实验，以确定非生物因素的变化如何将平衡转向一种群落状态或另一种状态。这种方法将首先在潮间带系统中发展，在那里，丝状绿藻在不受食草蜗牛控制的情况下可以形成广泛的藻垫，然后扩展到潮下群落，在那里，海胆的消耗会造成缺乏明显海带的贫瘠土地。在这两个系统中，我们将重点关注对比非生物因素（营养和水运动）的可变性如何允许早期脆弱阶段逃脱消费者的控制。研究结果不仅有助于一般生态学理论，而且对于理解沿海生态系统的功能以及解决应用问题（如富营养化）至关重要。