Faculty of Ecology, Evolution, and Environmental Sciences, School of Life Sciences, Arizona State University, Post Office Box 874501, Tempe, AZ 85287-4501, USA.
Science. 2010 Nov 12;330(6006):965-7. doi: 10.1126/science.1196005. Epub 2010 Oct 14.
Food chain length (FCL) is a fundamental component of food web structure. Studies in a variety of ecosystems suggest that FCL is determined by energy supply, environmental stability, and/or ecosystem size, but the nature of the relationship between environmental stability and FCL, and the mechanism linking ecosystem size to FCL, remain unclear. Here we show that FCL increases with drainage area and decreases with hydrologic variability and intermittency across 36 North American rivers. Our analysis further suggests that hydrologic variability is the mechanism underlying the correlation between ecosystem size and FCL in rivers. Ecosystem size lengthens river food chains by integrating and attenuating discharge variation through stream networks, thereby enhancing environmental stability in larger river systems.
食物链长度（FCL）是食物网结构的基本组成部分。在各种生态系统中的研究表明，FCL 由能量供应、环境稳定性和/或生态系统大小决定，但环境稳定性与 FCL 之间关系的性质，以及将生态系统大小与 FCL 联系起来的机制仍不清楚。在这里，我们表明 FCL 随排水面积的增加而增加，随水文变异性和间歇性的增加而减少，跨越了 36 条北美的河流。我们的分析进一步表明，水文变异性是河流中生态系统大小与 FCL 之间相关性的基础机制。生态系统大小通过溪流网络整合和减轻流量变化，从而增强较大河流系统的环境稳定性，从而延长河流食物链。
