Freshwater biodiversity is rapidly declining due to accelerated human-induced disturbances. Increased human-induced environmental disturbances are believed not to only decrease species numbers, but to also diminish beta diversity, for instance, by the local extinction of native species and wide-spread introduction of non-native species – a process widely known as biotic homogenization. Here, we investigated whether anthropogenic impacts reduce beta diversity. We also assessed the relative roles of environmental and spatial factors in driving beta diversity. We examined relationships among macroinvertebrates beta diversity, stream status classes (reference and impacted classes), and environmental predictors in streams in Northern Nigeria. We used PERMDISP and distance-based redundancy analysis followed by variation partitioning to evaluate how beta diversity of macroinvertebrates differed between the reference and impacted sites, and what mechanisms were responsible for their responses. While beta diversity between reference and impacted sites was similar for all distance matrices, there were significant differences in composition related to turnover between the reference and impacted sites using the distance matrices. Species sorting prevailed in structuring macroinvertebrates communities in our system, while spatial variables were not relevant. Our result of beta diversity of macroinvertebrates and their responses to disturbances support the hypothesis that disturbances do not necessarily lead to biotic homogenization. We recommend that tropical streams restoration ecologists need to emphasize the study of varying condition classes in their attempt to develop effective restoration strategies based on their environmental heterogeneity.

由于人为干扰的加剧，淡水生物多样性正在迅速下降。人们认为，人为引起的环境干扰增加不仅会减少物种数量，还会减少β多样性，例如，本地物种在当地灭绝和非本地物种的广泛引入——这一过程被广泛称为生物同质化. 在这里，我们调查了人为影响是否会降低 Beta 多样性。我们还评估了环境和空间因素在推动贝塔多样性方面的相对作用。我们研究了尼日利亚北部河流中大型无脊椎动物 β 多样性、河流状态类别（参考类别和受影响类别）和环境预测因子之间的关系。我们使用 PERMDISP 和基于距离的冗余分析，然后进行变异分区来评估大型无脊椎动物的 beta 多样性在参考站点和受影响站点之间有何不同，以及哪些机制对它们的响应负责。虽然所有距离矩阵的参考站点和受影响站点之间的 Beta 多样性都相似，但使用距离矩阵的参考站点和受影响站点之间与周转相关的组成存在显着差异。物种分类在我们系统中构建大型无脊椎动物群落方面占主导地位，而空间变量不相关。我们对大型无脊椎动物的 beta 多样性及其对干扰的反应的结果支持了干扰不一定会导致生物同质化的假设。