Structure and function of urban stream ecosystems

城市河流生态系统的结构与功能

• 批准号: 42799-2008
• 负责人: Morin, Antoine
• 金额: $ 1.36万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2011
• 资助国家: 加拿大
• 起止时间: 2011-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=474982
• 关键词: Structure; function; urban; stream; ecosystems

One of the most intriguing regularity in the structure of stream communities is that, although there is tremendous spatial and temporal variability in the abundance of various taxa and life stages, the size distribution is remarkably predictable. Our research has shown empirically that size distributions of stream organisms are correlated to physical habitat characteristics although the actual mechanisms underlying the patterns have not been tested. My students and I propose to test two hypothesized mechanisms that could account for the observed patterns. The first hypothesis states that available space, because of the fractal nature of stream beds, constrains densities of organisms of different size. The second hypothesis is that changes in trophic level with increasing size accounts for the general decline in abundance with increasing size. These two hypotheses will be tested in natural conditions by estimating available space for organisms of different sizes using close range digital photogrammetry techniques to describe habitat configuration at the mm scale, and by the use of nitrogen stable isotopes to estimate the average trophic level of organisms in different size classes.

河流群落结构中最有趣的规律之一是，尽管不同类群和生命阶段的丰度在空间和时间上存在巨大的变异性，但其大小分布是非常可预测的。我们的研究经验表明，河流生物的大小分布与物理栖息地特征有关，尽管这种模式背后的实际机制尚未得到测试。我和我的学生提议测试两种假设的机制，它们可以解释观察到的模式。第一种假设指出，由于河床的分形性质，可用空间限制了不同大小的生物体的密度。第二个假设是，随着体型的增加，营养水平的变化解释了随着体型的增加，物种数量普遍下降的原因。这两个假设将在自然条件下进行检验，方法是使用近距离数字摄影测量技术估计不同大小生物的可用空间，以描述毫米尺度的栖息地结构，并使用氮稳定同位素估计不同大小生物体的平均营养水平。