Abstract. The relations between environmental gradients, as measured by 19 independent variables, and traditional diversity indices (taxonomic richness, diversity and evenness) of benthic macroinvertebrate communities in the lotic systems of northern Italy were analyzed. Redundancy analysis (RDA) was used to describe the response of taxa to environmental gradients. Diversity indices were analyzed using generalized linear models (GLMs) with explanatory variables the first two major RDA axes. The results from RDA showed that taxa variance is mostly explained by altitude/latitude and combined pollution gradients. Taxonomic richness and diversity was higher in the low polluted upland sites (LPUs) in comparison to high polluted lowland sites (HPLs), suggesting that headwater streams have higher taxonomic richness than downstream reaches. On the other hand, evenness was lower in LPUs, probably due to the dominance of some taxa (e.g., Plecoptera) that are more tolerant of colder conditions.

中文翻译：

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意大利北部激流系统底栖无脊椎动物环境梯度与多样性指数的关系

摘要。分析了由 19 个自变量测量的环境梯度与意大利北部水流系统中底栖大型无脊椎动物群落的传统多样性指数（分类丰富度、多样性和均匀度）之间的关系。冗余分析 (RDA) 用于描述分类群对环境梯度的响应。使用广义线性模型 (GLM) 分析多样性指数，解释变量是前两个主要 RDA 轴。RDA 的结果表明，分类群差异主要由海拔/纬度和综合污染梯度来解释。与高污染低地地点 (HPL) 相比，低污染高地地点 (LPU) 的分类丰富度和多样性更高，这表明上游河流的分类丰富度高于下游河段。