Distribution of aquatic insects in urban headwater streams

Abstract

AIMS: The objective of this study was to evaluate the effects of urban environments on the distribution and occurrence of aquatic Ephemeroptera, Plecoptera and Trichoptera (EPT) insects in six urban subtropical streams; METHODS: Organisms were collected with a Surber sampler in 2005 and 2006, over two hydrological cycles. We analyzed abundance values, taxonomic richness, Shannon-Wiener diversity and Pielou's evenness. A principal components analysis (PCA) was performed to evaluate the environmental variability of streams. A canonical correspondence analysis (CCA) was performed to evaluate the possible effects of environmental variables; RESULTS: The PCA ordered the streams according to their quality, and Suzana and Nadau streams had higher concentrations of nutrients. The Baetidae (Ephemeroptera) was the family with the highest number of genera (18). Perissophlebiodes Savage, 1983, and Americabaetis Kluge, 1992, were the most common genera. Anacroneuria Klapálek, 1909, was the most abundant Pleocoptera, and Smicridea McLachlan, 1871, was the dominant Trichoptera genus. In the CCA, pH, electrical conductivity and stream velocity were positively correlated with axis 1, whereas dissolved oxygen was negatively correlated with axis 1; CONCLUSIONS: Our results show that the distribution of EPT in urban streams is affected by changes in water physicochemical characteristics. However, these changes are not sufficiently severe to cause the elimination of EPT.

Aquatic Insect Biodiversity and Water Quality Parameters of Streams in Northern Thailand

“…A desirable habitat quality is generally characterized by a heterogeneous habitat with both slow and fast moving water, woody debris, substrate variety, and well-vegetated, stable banks (Galuppo et al 2007). Impairment of habitat and water chemistry can lead to the reduced diversity of aquatic macroinvertebrates (Hepp et al 2013).…”

“…Most importantly, aquatic insects are very good indicators of water quality since they have various environmental disturbance tolerance levels (Arimoro & Ikomi 2008). Some are very vulnerable and sensitive to pollution, while others can live and proliferate in disturbed and extremely polluted waters (Hepp et al 2013;Merritt & Cummins 1996). Anthropogenic activities of humans such as releases from domestic sewage, run-off from agricultural lands, laundering into streams and mining activities.…”

“…temperature, dissolved oxygen, alkalinity, phosphates, nitrates and metal concentrations. Variations in these water properties greatly influence the distribution patterns of aquatic insects in the water since some of them are highly sensitive to pollution while others are somewhat tolerant or completely tolerant to pollution and environmental disturbances (Hepp et al 2013).…”

The effects of heavy metals on the incidence of morphological deformities in Chironomidae (Diptera)

“…Urban effluents are significant sources of chlorides in the water surface, which influence the variation in electrical conductivity (Santos 2010, Hepp et al 2013). Similarly, as solids dissolved in water indicate the presence of salts, a correlation between dissolved solids and electrical conductivity is expected (Porto et al 1991).…”

“…Riparian vegetation does not always guarantee water quality if there is a source of contamination at the site. The great problem of urban water bodies lies in the fact that they receive domestic waste in natura (Hepp et al 2013). In this case, the domestic effluents are dumped directly into the river under study, since in P2 there is an upstream housing complex, which explains the high concentrations of Zn.…”