Taxonomic and functional macrofaunal diversity along a gradient of sewage contamination: A three-year study

• Published in: Environmental pollution (1987) Vol. 323; p. 121022
• Main Authors: Nasi, Federica, Vesal, Seyed Ehsan, Relitti, Federica, Bazzaro, Matteo, Teixidó, Nuria, Auriemma, Rocco, Cibic, Tamara
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.04.2023; Elsevier
• Subjects: Beta-diversity component; Biodiversity; Carbon; Ecosystem; Environmental Sciences; Functional entities; Functional space; Macrofaunal community; Northern Adriatic sea; Sewage; Sewage effluent disposal; Water; Functional entities; Macrofaunal community; Sewage effluent disposal; Northern Adriatic sea; Functional space; Beta-diversity component; field sampling; data interpretation; Environmental Pollution FN: manuscript preparation conceptualization data interpretation statistical analysis macrofaunal community analyses field sampling. SEV: macrofaunal community analyses field sampling; macrofaunal community analyses; field sampling. SEV: macrofaunal community analyses; Environmental Pollution FN: manuscript preparation; conceptualization; statistical analysis
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2023.121022

We investigated the structural and functional changes of the soft-bottom macrofaunal community following the improvement of a wastewater treatment-WWT plant. The macrofauna was collected at increasing distance from the main outfall in 2018, 2019, and 2021. Organic matter and nutrients were analysed in the water column near the outfalls to detect possible changes due to the improved treatment. We examined Functional Entities-FEs (i.e. a unique combination of species functional traits), species richness, Shannon-Wiener diversity-H′, and taxonomic and functional β-diversity. From 2018 (before the year of the treatment change), to 2021, we noted a gradual decrease of organic carbon in the water column. In contrast, sediment characteristics (i.e. grain-size) did not change before and after treatment enhancement, with the exception of redox potential. Species richness and FEs gradually increased moving far from the source of organic contamination and after wastewater treatment enhancement, especially near the outfall. We observed different phases of macrofaunal succession stage after the WWT amelioration. A ‘normal stage’, i.e. slightly lower species richness, was reflected in decreasing functional richness. Higher taxonomic β-diversity values with significant turnover components indicated that the community was subjected to broad changes in species composition. However, functional β-diversity did not follow the same pattern. After treatment improvement, modified environmental conditions led to the establishment of new species, but with the same functions. Towards 2021, the community improved its resilience by increasing functional redundancy and reduction of vulnerability, which enhanced community stability. The latter was also reflected in the well-balanced proportion of macrofaunal feeding habits after the WWT upgrade. Integrating the classical taxonomic approach with the analysis of FEs, and environmental characteristics can provide an accurate insight into macrofauna sensitivity to stressors that are likely to lead to changes in the ecological state of an area. [Display omitted] •The WWT improvement induced variation in species composition and functions.•The species richness and the functional diversity increased at the area nearby the outfall.•The community enhanced its resilience with higher functional redundancy.•FEs, α and β-diversity are ideal for detecting community changes following the WWT upgrade.