Department of Biological Sciences, Eastern Illinois University, Charleston, IL 61920, USA.
Environ Manage. 2010 Nov;46(5):761-70. doi: 10.1007/s00267-010-9551-x. Epub 2010 Sep 9.
Stream habitat assessments are conducted to evaluate biological potential, determine anthropogenic impacts, and guide restoration projects. Utilizing these procedures, managers must first select a representative stream reach, which is typically selected based on several criteria. To develop a consistent and unbiased procedure for choosing sampling locations, the Illinois Department of Natural Resources and the Illinois Natural History Survey have proposed a technique by which watersheds are divided into homogeneous stream segments called valley segments. Valley segments are determined by GIS parameters including surficial geology, predicted flow, slope, and drainage area. To date, no research has been conducted to determine if the stream habitat within a valley segment is homogeneous and if different valley segments have varying habitat variables. Two abutting valley segments were randomly selected within 13 streams in the Embarras River watershed, located in east-central Illinois. One hundred meter reaches were randomly selected within each valley segment, and a transect method was used to quantify habitat characteristics of the stream channel. Habitat variables for each stream were combined through a principal components analysis (PCA) to measure environmental variation between abutting valley segments. A multivariate analysis of variance (MANOVA) was performed on PCA axes 1-3. The majority of abutting valley segments were significantly different from each other indicating that habitat variability within each valley segment was less than variability between valley segments (5.37 ≤ F ≤ 245.13; P ≤ 0.002). This comparison supports the use of the valley segment model as an effective management tool for identifying representative sampling locations and extrapolating reach-specific information.
河流生境评估用于评估生物潜力、确定人为影响并指导修复项目。利用这些程序，管理者必须首先选择一个具有代表性的河流段，通常根据几个标准进行选择。为了开发一种一致且无偏的选择采样地点的程序，伊利诺伊州自然资源部和伊利诺伊州自然历史调查提出了一种技术，将流域划分为同质的河流段，称为河谷段。河谷段由 GIS 参数确定，包括地表地质、预测流量、坡度和汇水面积。迄今为止，还没有研究来确定河谷段内的河流生境是否同质，以及不同的河谷段是否具有不同的生境变量。在伊利诺伊州中东部的埃马布拉斯河流域的 13 条溪流中，随机选择了两个相邻的河谷段。在每个河谷段内随机选择 100 米的河段，并使用横断面方法来量化河流通道的生境特征。通过主成分分析（PCA）将每条溪流的生境变量组合在一起，以测量相邻河谷段之间的环境变化。对 PCA 轴 1-3 进行了多元方差分析（MANOVA）。大多数相邻的河谷段彼此之间存在显著差异，表明每个河谷段内的生境变异性小于河谷段之间的变异性（5.37≤F≤245.13；P≤0.002）。这种比较支持使用河谷段模型作为一种有效的管理工具，用于识别具有代表性的采样地点并推断特定河段的信息。
