Abstract Freshwater resources are under stress because of anthropogenic activities and the demand for water increasing on a global scale, including hydropower. There are presently plans to expand the use of hydropower within eastern and southern Africa. A key river system identified as a potential source of energy is the Pungwe River, with the proposed Pavua Dam located within the middle reaches of the system in Mozambique. However, impoundments have been recorded to negatively influence ichthyofauna communities via alterations to water quality and discharge. Furthermore, information on the structure of the ichthyofauna community, community spatial shifts and fine-scale habitat preferences for the region are lacking. Accordingly, the research sought to address this issue, to provide baseline data as well as inform on management of the system. Ichthyofauna were collected utilising an array of passive and active techniques and species data modelled to fit spatial factors to ascertain spatial shifts. To ascertain fine-scale habitat preferences, fourth-corner modelling was undertaken to link mouth position and body shape traits to substrate composition and cover features. Spatial heterogeneity in environmental characteristics caused by the intrusion of the African Rift Valley had driven significant spatial shifts in the ichthyofauna community, with distinct groups of species occurring within the sample sites. The findings of the study indicated that the ichthyofauna community within the Muazi River were significantly different to the Pungwe River and the community will be lost from the region because of the dam footprint. Furthermore, habitat preferences were influenced by mouth position and body shape. Consequently, alteration to environmental characteristics and habitat features is likely to negatively influence the ichthyofauna community.

中文翻译：

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莫桑比克蓬圭盆地中下游地区鱼群的空间变化和栖息地划分

摘要 由于人为活动和包括水电在内的全球范围内对水的需求增加，淡水资源面临压力。目前有计划在非洲东部和南部扩大水电的使用。被确定为潜在能源的主要河流系统是 Pungwe 河，拟建的 Pavua 大坝位于莫桑比克该系统的中游。然而，已记录蓄水通过改变水质和排放对鱼群群落产生负面影响。此外，还缺乏有关该地区鱼群群落结构、群落空间变化和细尺度栖息地偏好的信息。因此，该研究试图解决这个问题，以提供基线数据以及系统管理信息。利用一系列被动和主动技术和物种数据收集鱼群，以适应空间因素以确定空间变化。为了确定精细尺度的栖息地偏好，进行了第四角建模，将嘴部位置和身体形状特征与基质成分和覆盖特征联系起来。由非洲大裂谷的入侵引起的环境特征的空间异质性驱动了鱼群群落的显着空间变化，样本点内出现了不同的物种群。研究结果表明，木子河内的鱼群群落与蓬圭河显着不同，由于大坝足迹，该群落将从该地区消失。此外，栖息地偏好受嘴部位置和体型的影响。因此，环境特征和栖息地特征的改变可能会对鱼群群落产生负面影响。