Relationships between macroinvertebrate communities and environmental variables in metal‐contaminated streams in south‐west England

Abstract

1. Macroinvertebrate species and information on thirty-nine variables were recorded at forty-six sites on twelve Cornish streams affected to varying extents by past metalliferous mining. 2. Relationships between macroinvertebrate communities and environmental variables were examined using canonical correspondence analysis (CCA). Copper was the strongest correlate with Axis 1 of the analysis, suggesting that it may have a major role in determining community structure. There were also strong correlations between Axis 1 and aluminium, alkalinity, pH, dissolved organic matter and algal cover, and between Axis 2 and discharge.3. CCA distinguished four site groupings. In spite of seasonal changes in position on the ordination, as revealed through CCA and detrended correspondence analysis (DCA), sites retained their group membership. There were differences in the proportions of the major taxa within the four CCA-derived groups. In the group with the highest copper concentration, Ephemeroptera were absent, but triclads and chironomids were abundant, with Orthocladiinae the dominant group. 4. Changes in the occurrence of spedes along the metal gradient reflected changes in sensitivity. 'Tolerance' plots of selected species based on the CCA site ordination diagram were used to identify environmental thresholds. 5. As well as direct toxic effects of copper and aluminium on invertebrate communities, co-precipitation of these two metals could be an important physical factor. Further modifying influences resulting from interactions between toxic metals and pH, alkalinity, hardness and dissolved organic matter contributed to the complexity of conditions affecting the faunat community in metal-contaminated streams. 6. The most severely contaminated sites, with mean copper concentration exceeding 500(xgp', were all characterized by a reduced community dominated by the flatworm Phagocata vitta, the chironomids Chaetocladius melaleucus and Eukiefferielia claripennis and the net-spinning caddis Plectrocnemia conspersa. The necessity for spedes identification is demonstrated in relation to variation in metal tolerance.

Investigating the influence of heavy metals on macro-invertebrate assemblages using Partial Cononical Correspondence Analysis (pCCA)

“…Limitations of both the laboratory and field based investigations have been well documented (LaPoint et al, 1984;Gower et al, 1994Gower et al, , 1995. To overcome deficiencies of these techniques, investigations that model macroinvertebrate assemblages from environmental variables that include 'natural' stress parameters and contaminants have been used (Gower et al, 1994(Gower et al, , 1995Nelson and Roline, 1999;Reinhold-Dudok van Heel and den Besten, 1999;Brown and May, 2000). There is a paucity of research relating macroinvertebrate and environmental contaminants, especially bioavailable sediment metal concentrations.…”

“…Research has been focused on the association between heavy metals and vehicles (Andoh, 1994;Marsalek et al, 1999), predominantly on heavily trafficked roads, such as motorways (Shutes, 1984;Maltby et al, 1995aMaltby et al, , 1995b. Limitations of both the laboratory and field based investigations have been well documented (LaPoint et al, 1984;Gower et al, 1994Gower et al, , 1995. To overcome deficiencies of these techniques, investigations that model macroinvertebrate assemblages from environmental variables that include 'natural' stress parameters and contaminants have been used (Gower et al, 1994(Gower et al, , 1995Nelson and Roline, 1999;Reinhold-Dudok van Heel and den Besten, 1999;Brown and May, 2000).…”

“…Generally, increasing urbanization and road construction means that heavy metals derived from non-point sources are likely to cause further impairment of stream ecology but current knowledge of metal contamination is related primarily to point and downstream measurements from known sources (Garcia-Criado et al, 1999;Gower et al, 1994Gower et al, , 1995Griffith et al, 2001;Nelson and Roline, 1999), from sampling at sites where problems were anticipated (Perdikaki and Mason, 1999) and toxicity assays (Tucker and Burton, 1999). While control measures for point source discharges have improved water quality, streambed sediments remain the major repositories of urban contaminants, the spatial ranges and degrees of which are largely unknown.…”

Relationship between aquatic insects and heavy metals in an urban stream using multivariate techniques

“…Thus, knowledge of their toxicity to aquatic organisms is important (Sprague, 1985;Murthy, 1986;Rattner and Heath, 1995;Beasley and Kneale, 2003;Rathore and Khangarot, 2003;Suthar and Sing, 2008;Nakane and Haidary, 2010). Generally, increasing urbanization and road construction means that heavy metals derived from non-point sources are likely to cause further impairment of stream ecology but current knowledge of metal contamination is related primarily to point and downstream measurements from known sources (Gower et al, 1994(Gower et al, , 1995Garcia-Criado et al, 1999;Nelson and Roline, 1999;Babel and Opiso, 2007;Zvinowanda et al, 2009;Sekabira et al, 2010). Endangered wetland ecosystems are getting much attention and the importance of insects in these environments is being acknowledged.…”

Sediment geochemistry of streams draining abandoned lead/zinc mines in central Wales: the Afon Twymyn

“…Contaminated drainage from abandoned metal mines and mine spoil are issues of international concern that can severely impact hydrological (Grimshaw et al 1976;Gammons et al 2005), sedimentological (Macklin et al 2006;Dennis et al 2009) and ecological (Gower et al 1994;Armitage et al 2007) systems. The varied geology of the UK has provided many valuable natural resources and mineral exploration has occurred since the early Bronze Age (Environment Agency 2008a).…”