Chironomid distribution along a pollution gradient in Ethiopian rivers, and their potential for biological water quality monitoring

Abstract

Water pollution resulting from the rapidly intensifying use of freshwater resources in Ethiopia is increasing the need for continuous follow-up and monitoring of the country's aquatic ecosystems, in order to maintain their biological diversity and water quality. Chironomids (non-biting dipteran midges) are often used for biological water quality assessment because their larvae tend to respond rapidly and sensitively to changes in the aquatic environment. Larval chironomid assemblages from 37 sites in 20 Ethiopian rivers were analysed in 2010 to assess the relationship between species composition and water quality. Cluster analysis of local physical and chemical variables was used to classify sites into three different water quality classes: 15 sites were classified as not or slightly polluted, 16 as moderately polluted and six as heavily polluted. We recovered 21 chironomid taxa, representing three subfamilies, with Chironominae (13 taxa) making the largest contribution, followed by Tanypodinae and Orthocladinae (four taxa each). Polypedilum nubifer, P. wittei, Polypedilum type Wabe, Cryptochironomus sp. and Conchapelopia sp. were the dominant species in unpolluted or slightly polluted sites. Chironomus alluaudi and C. imicola were indicators of heavily polluted sites, typified by low (<2 mg l(-1)) concentrations of dissolved oxygen. Heavily polluted sites, such as the Modjo and Sebata rivers, also held a lower number of species and genera than less-impacted sites. Larval chironomid assemblages proved useful as indicators of river water quality in Ethiopia when taxa are identified at the species and/or genus level

Can Macroinvertebrate Assemblage Changes Be Used as Biological Indicator of Water Quality of the Nokoue Lake (Benin)?

“…Indeed, Chironomidae multiply in environmental conditions difficult to bear for other taxa (Shannon diversity and equitability low but high indices Simpson) and reflect an environment polluted with high FBI. This biological capacity of organic pollution by Chironomidae larvae was proven by [29] and confirmed by [58] respectively in the Niger River and the Ethiopian rivers. There was also a positive correlation between diversity and the percentage of insects.…”

Molecular data extend AustralianCricotopusmidge (Chironomidae) species diversity, and provide a phylogenetic hypothesis for biogeography and freshwater monitoring

“…Moreover, C. albitibia group species from outside Australia possess broad tolerances to impact (e.g. Beneberu et al ., ). Possibly the common ancestor of C. albitarsis + C. wangi was tolerant to ecosystem impact, and the subsequent specialization of C. wangi represents diversification into a vacant niche.…”

“…Cricotopus albitibia , reported originally from Sierra Leone (Freeman, ), is widespread in sub‐Saharan Africa (e.g. Scott, ; Hughes, ; Dejoux, ; Beneberu et al ., ). Specimens from New South Wales (NSW), Australian Capital Territory (ACT), and Western Australia were believed to be conspecific by Freeman ().…”

Bioindicators assessing water quality and environmental impacts of water treatment plant sludge

“…Traditionally, the assessment of these environmental impacts is accomplished by measuring chemical and physical variables (CONAMA, 2005;Fonseca et al, 2014;WHO, 1996). However, many authors (Beneberu et al, 2014;Bere and Tundisi, 2012;Calderon et al, 2014;Rinaldi, 2007) state that the use of biological responses as environmental degradation indicators are more advantageous compared to chemical and physical parameters since these non-biological measurements only represent a snapshot of the moment they were collected. This means a large number of samples to evaluate temporal variation are required.…”