How to Improve the Biological Quality of Urban Streams? Reviewing the Effect of Hydromorphological Alterations and Rehabilitation Measures on Benthic Invertebrates

Abstract

Urbanisation alters the natural hydromorphology of streams, affecting aquatic communities and ecological quality. Increasing efforts have been put into the rehabilitation of urban streams due to their importance for urban sustainability. Despite these efforts, many projects fail to achieve the improvement of aquatic communities. This study aims to provide specific recommendations to enhance the biological rehabilitation of urban streams by reviewing: (i) the impacts of urbanisation and climate change on urban stream hydrology, (ii) the responses of invertebrate assemblages to alterations in the hydrology and morphology of streams, and (iii) the hydromorphological rehabilitation measures applied to streams and their effect on invertebrate communities. This review found that commonly employed measures of habitat heterogeneity enhancement (such as the addition of meanders, boulders, and artificial riffles) are not enough to improve invertebrate communities. On the other hand, the most effective measures are those leading to the re-establishment of natural hydrological patterns and good water quality. Ultimately, an integrated ecohydrological approach that considers the entire watershed and its interactions between ecosystems and anthropological activities is the key to managing and rehabilitating urban streams.

Benthic Macroinvertebrates Associated with Riparian Habitat Structural Diversity in an Eastern Amazon Stream Urbanization Gradient

“…However, our second hypothesis was partly supported since natural areas had, as predicted, higher sediment heterogeneity. Catchment modification, land use and local or stream reach habitat conditions and river flow runoff influence hydrodynamics and the particle size of sediments and their transport or deposition (Silva et al, 2007;Zerega et al, 2021). The highest percentages of gravel were found in altered and impacted areas, where accelerated erosive processes occur, associated with the removal of riparian vegetation (Martins et al, 2021b), lower RHDI scores and as a likely result of rapid washout, fine sand and very fine sand were consistently lower and highly variable in Altered and Impacted areas, respectively.…”

“…Brazil has rich freshwater biodiversity (Azevedo-Santos et al, 2019) increasingly threatened by unsustainable activities (Pelicice et al, 2017;Tófoli et al, 2017;Daga et al, 2020;Nobile et al, 2020), mainly deforestation and unplanned urbanization, which impact on hydrology and water quality (Piazza et al, 2017;Côrtes and Silva Júnior, 2021;Zerega et al, 2021). These impacts are progressively spreading throughout the Brazilian Amazon, especially in smaller streams and creeks (Helson and Williams, 2013;de Paiva et al, 2021).…”

“…Urbanization is the second largest cause of habitat destruction worldwide, and one of the greatest threats to freshwater biodiversity (Ellis et al, 2010;Hill et al, 2015). Increased urbanization equates to deteriorating water quality, an altered hydrological regime and reduced habitat diversity (Luo et al, 2017;Piazza et al, 2017;Zerega et al, 2021;Iñiguez-Armijos et al, 2022) due to land use impacts in the surrounding catchment, pollution, urban surface impermeability and removal of riparian vegetation causing losses in aquatic biodiversity (de Paula et al, 2021), such as that of stream macroinvertebrates (Feio and Teixeira, 2019;Dala-Corte et al, 2020;Sundar et al, 2020;Zerega et al, 2021).…”

The Impacts of Precipitation on Fluorescent Dissolved Organic Matter (FDOM) in an Urban River System

“…Urban rivers also serve as spillways for flood discharge in cities with frequent rainstorms [9][10][11][12]. Due to the aggregated functions of urban rivers, their water quality is of significant importance [13][14][15][16].…”