Urbanization impacts water quality and the use of microhabitats by fish in subtropical agricultural streams

Abstract

Summary Land-use changes have negative effects on stream conditions and fish assemblages, but their effects on water quality and the use of microhabitats by fish in subtropical lowland streams are unclear. We evaluated the effects of urban patches (two urban streams) in an agricultural matrix (two ‘agricultural’ streams) on water quality, microhabitat diversity and fish assemblages, as well as the selection of microhabitat types by fish in the Arroyo Colorado basin (Uruguay). Physicochemical water parameters were measured, the fish sampled using electrofishing, microhabitat diversity, occupancy of microhabitats by fish and the most important microhabitat types for fish species were analysed. Agricultural streams presented higher water quality and microhabitat diversity, and most of the microhabitats were occupied by fish. Microhabitats with medium substrate sizes and running water prevailed in urban streams, while the presence of macrophytes, shallow waters and different substrate sizes were common in agricultural streams. The most important microhabitats used by fish species were not the most abundant, highlighting the fragility of streams resulting from the loss of appropriate conditions. Understanding how different degrees of deterioration in streams affect water quality and microhabitat–fish interactions is essential for the designing of effective monitoring and restoration programmes.

Orchards and paddy differentially impact rock outcrop amphibians: Insights from community- and species-level responses

“…Land-use was an important driver influencing amphibian prevalence. While most studies focus on determining the impacts of land-use change on diversity or species responses, the proximate drivers of change (e.g., loss of microhabitats) are infrequently documented (but see Barrios & Mello, 2022; Sueyoshi et al, 2016; Wood et al, 2017). Microhabitat changes can impact adult frog dispersion, larval occurrence, and morphology (Marques et al, 2018).…”

Community-Driven Insights into Fish Assemblage, Microhabitats, and Management Strategies in the Meghna River Basin of Bangladesh

“…However, overfishing, anthropogenic pressure, unplanned flood control, and deficiencies in irrigation infrastructures also lead to the destruction of river ecosystems [9]. Especially microhabitats, where fish spend all or part of their time avoiding predatory species or reducing interaction with competitors in competition for food, are affected by these changes [10]. Convenient fish habitat is a crucial factor for the robustness and sustainability of fish populations [11].…”