Aquatic systems have been degraded by environmental changes aimed at increasing the productivity of farmland and ranches. These changes affect aquatic assemblages at both local and regional scales. The hypothesis of this study is that in-stream environmental conditions are more important determinants of species richness and composition of Gerromorpha assemblage, given that they are affected directly by changes that occur within the stream, rather than by landscape conditions. To test our hypothesis, we collected at 20 sites of agricultural and forested regions in the Brazilian Cerrado. We relate predictors of the landscape and sites, of the streams with the assemblages of Heteroptera. While landscape metrics play an important role in the formation of stream conditions, local and physico-chemical variables had a significant influence on the structure of the Gerromorpha assemblages in the study area. This indicates that these organisms are more dependent on the processes that occur within the stream than those that occur outside the area of the gallery forest, considering the spatial scale of this study.

中文翻译：

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局部变量和景观度量标准对巴西萨凡纳溪流中的Gerromorpha（Insecta：Heteroptera）组合的影响。

为了增加农田和牧场的生产力，环境变化使水生系统退化。这些变化影响了地方和区域规模的水生生物。这项研究的假设是，河内环境条件是更重要的决定物种物种丰富度和Gerromorpha组合组成的因素，因为它们直接受到河内发生的变化的影响，而不是受景观条件的影响。为了检验我们的假设，我们在巴西塞拉多的20个农业和森林地区进行了采集。我们将景观和地点，溪流的预测因子与异翅目的组合联系起来。尽管景观指标在河流条件的形成中起着重要作用，局部和理化变量对研究区域Gerromorpha组合的结构有重要影响。这表明，考虑到本研究的空间规模，这些生物比在林间森林以外的生物更依赖溪流内的生物。