Macroinvertebrate Assemblages along the Longitudinal Gradient of an Urban Palmiet River in Durban, South Africa.

Urban rivers are regarded as unnatural because they drain catchments characterized by impervious surfaces. The present study explored macroinvertebrate communities in relation to water and habitat quality along the longitudinal gradient of an urban Palmiet River in Durban, South Africa. Sampling was conducted across six sites along the river. The water quality has shown a significant variation (ANOVA, p < 0.05) across six sites. Good-quality water was observed at Site 6, whereas Site 5 exhibiting hypertrophic condition. Sites 4 to 1 were all eutrophic; however, nutrient levels showed to decrease from Site 4 down to Site 2 and increased again at Site 1. A similar trend was observed for habitat quality, with Site 6 showing excellent and Site 5 exhibited poor habitat. Coinciding with water and habitat quality, macroinvertebrate diversity and abundance showed significant differences across six sites. Sensitive palaemonids, notonemourids, and amphipods were only observed in the headwaters and have contributed over 50% of the variation in abundance between Site 6 and other sites. The non-metric multidimensional scaling (NMDS) plot has also shown clear discrimination (MANOVA, p < 0.001) for the Average Score Per Taxon (ASPT) across the six sites. Macroinvertebrate communities have shown a clear association between water and habitat quality. These findings affirm the ecological importance of urban rivers as they provide refuge to aquatic biodiversity, with anthropogenic litter providing additional habitats for other taxa. Despite the current conditions supporting biodiversity and the functioning of the river, it is unclear if the system could endure further disturbance.

Data of macroinvertebrates assemblage across different stretches of an urban Palmiet River in Durban, South Africa.

Urban rivers have been overlooked as they are regarded as unnatural with poor ecological conditions to support aquatic life. This dataset presents the abundance and taxa richness of macroinvertebrates collected in an urban Palmiet River, which showed highly variable stretches with respect to water quality and physical habitat availability. A YSI 556 MPS handheld multiparameter instrument was used to measure physical variables of the water, whereas samples were taken using sampling bottles and kept in the fridge prior to nutrient analysis. Habitat assessment was carried out following the integrated habitat assessment score (IHAS) protocol. Macroinvertebrates were collected using modified SASS5 protocol, where stone, vegetation, and gravel sand, and mud biotopes were sampled. Macroinvertebrates were identified to family levels, and abundance and taxa richness were calculated. This data affirms the capacity of urban rivers to harbor aquatic biota and to self-purify along the longitudinal gradient. The data further attest that the response of urban rivers to anthropogenic activities does not differ from natural streams, and the assemblage of macroinvertebrates is driven by water quality and physical habitat. Moreover, the role played by anthropogenic litter in the absence of natural habitat is stressed. Lastly, this data can guide urban ecologists when designing studies for highly variable urban river systems as it illustrates the dynamics of urban ecosystems and their potential to harbor aquatic biota.