Soballe D M, Kimmel B L
Ecology. 1987 Dec;68(6):1943-1954. doi: 10.2307/1939885.
We analyzed two large data sets (the National Stream Water Quality Accounting Network and the National Eutrophication Survey) to compare quantitatively the ecological structure and function of rivers, river impoundments, and natural lakes on a broad scale. Discriminant analysis with physical-chemical variables separated these three types of aquatic systems along a composite gradient that correlated with water residence time (r = 0.7), drainage area (r = 0.7), water depth (r = 0.6), stream flow (r = 0.6), and water clarity (r = 0.4). Natural lakes and rivers occupied opposite ends of this gradient, and reservoirs, on average, were intermediate, but natural lakes and impoundments overlapped extensively and did not form a useful dichotomy. Regression analysis showed algal abundance per unit phosphorus increasing in the sequence: rivers < impoundments < natural lakes, which paralleled intergroup differences in residence time. Algal abundance per unit phosphorus did not differ significantly among these three system types when systems with similar residence times were compared. Our results indicate that water residence time is a useful system-level index that has similar ecological implications for rivers, lakes, and reservoirs.
我们分析了两个大型数据集（国家河流水质核算网络和国家富营养化调查），以便在大尺度上对河流、河流水库和天然湖泊的生态结构和功能进行定量比较。利用物理化学变量进行的判别分析，沿着与水停留时间（r = 0.7）、流域面积（r = 0.7）、水深（r = 0.6）、水流（r = 0.6）和水体透明度（r = 0.4）相关的综合梯度，将这三种类型的水生系统区分开来。天然湖泊和河流位于该梯度的两端，而水库平均处于中间位置，但天然湖泊和水坝形成的水库有广泛重叠，并未形成有效的二分法。回归分析表明，单位磷含量的藻类丰度按以下顺序增加：河流＜水库＜天然湖泊，这与组间停留时间的差异相似。当比较停留时间相似的系统时，这三种系统类型中单位磷含量的藻类丰度没有显著差异。我们的结果表明，水停留时间是一个有用的系统层面指标，对河流、湖泊和水库具有相似的生态意义。
