Assessment of ecological water quality along a rural to urban land use gradient using benthic macroinvertebrate-based indexes

Abstract

Agricultural practices such as livestock grazing and tilling can result in soil erosion and runoff of fine sediments, nutrients (e.g. nitrogen, phosphorus, potassium) and pesticides, leading to degradation of aquatic environments. Urbanization is also responsible for a variety of impacts on fluvial ecosystems, including pollution by heavy metals, oil, domestic sewage and garbage. In this study, we evaluate the impact of land use on stream health of the Uberabinha river catchment. Overall, rural streams presented better ecological conditions than urban streams. Both species composition and abundance of benthic communities showed significant differences between rural and urban streams. Urban streams presented a higher dominance of Oligochaeta, Hirudinea and Gastropoda, bioindicators of poor water quality. Rural streams presented significantly greater richness and diversity. Compared to urban streams, rural streams presented a significantly higher number of Ephemeroptera, Plecoptera, Trichoptera, Odonata and Hemiptera taxa. Our analyses also showed congruence (high correlation) among the classical biodiversity metrics (Shannon-Wiener index -H', Pielou's measure of eveness -J) and monitoring parameters (% Ephemeroptera, Plecoptera and Trichoptera -EPT, Biological Monitoring Work Party -BMWP, bioindicator approach and Rapid Assessment Protocol -RAP, a habitatbased approach). Five from seven rural streams presented good water quality according to both BMWP and RAP and none of the urban streams presented good water quality. Our results show that the urban streams of Uberlândia municipality are poor ecosystems, and require improved management actions by environmental authorities. We also encourage that the riparian forest restoration and management carried out in the upper portion of Uberabinha River catchment to be extended to the urban area of the municipality.

Relating environmental variables with aquatic community structure in an agricultural/urban coldwater stream

“…For example, while previous findings in the lowland Swiss Mönchaltorfer Aa catchment showed that EPT richness was highest in least impacted sites mostly upstream of urban and agricultural areas, our greatest EPT richness was along sites IMC4 and IMC5, which are in wellforested reaches downstream of the agricultural areas but within the urban zone (Baumgartner and Robinson 2017). Also, contrary to findings from Brazil's Uberabinha river catchment and Chile's Mediterranean ecoregion, we did not find urban reaches to have less richness or diversity of sensitive taxa than agricultural reaches in the Indian Mill Creek watershed (Nascimento et al 2018;Fierro et al 2019). This divergence from other catchments suggests that one possible reason for this increase in EPT richness is that there is a forested section of the middle Indian Mill Creek watershed within the urban zone, which provides habitats and shelter for aquatic organisms (Fig.…”

“…The feeding guilds and other traits of stream organisms can also reflect environmental variables (Usseglio- Polatera et al 2000;Merritt et al 2006). The composition of aquatic communities can be vastly different depending on the land use surrounding streams, for instance urban and agricultural areas (Nascimento et al 2018), as well as longitudinally (Vannote et al 1980). Low-agriculture areas with extensive vegetation buffers may support the greatest biological integrity for aquatic communities because of the habitats there, such as pools and woody debris (Effert-Fanta et al 2019).…”

“…Low-agriculture areas with extensive vegetation buffers may support the greatest biological integrity for aquatic communities because of the habitats there, such as pools and woody debris (Effert-Fanta et al 2019). Conversely, urban areas often have the lowest richness and diversity of aquatic macroinvertebrates (Nascimento et al 2018;Fierro et al 2019).…”

Application of the Lake Biotic Index (LBI) in the ecological characterization of a North Patagonian lake in Chile

“…Bioindicators of environmental impact based on benthic macroinvertebrates gained special relevance in Europe (Dermott and Pachkevitch, 2012). However, in Chile and South America they are mostly used to assess the ecological condition of rivers (Brand and Miserendino, 2015;Cardoso and Novaes, 2013;Correa-Araneda, 2016;Correa-Araneda et al, 2010;Dedieu et al, 2016;Dos Santos, 2017;Fierro et al, 2016;Figueroa et al, 2003;Kay et al, 2001;Lallement et al, 2014;Luo et al, 2018;Meza-S et al, 2012;Miserendino et al, 2012;Nascimento et al, 2018).…”

RELAÇÃO DA INTEGRIDADE AMBIENTAL E A BIOLOGIA DE Serrapinnus notomelas (CHARACIDAE) EM CÓRREGOS URBANOS

“…Os ecossistemas aquáticos são formados por interações complexas entre fatores bióticos e abióticos e estes têm sofrido alterações significativas como resultado das intensas atividades antrópicas, como lançamento de efluentes domésticos e industriais não tratados, desmatamento, atividades agrícolas, construção de barragens e represas, entre várias outras atividades (Goulart & Callisto 2003, Nascimento et al 2018. Entre as principais alterações que ocorrem nesses ecossistemas, Callisto et al (2005) ressaltam a redução da biodiversidade aquática como consequência da desestruturação do ambiente físico, químico e biológico, resultando em perda de qualidade e dificuldade na manutenção da integridade ambiental desses ecossistemas aquáticos.…”