TY - JOUR

T1 - A catchment scale evaluation of multiple stressor effects in headwater streams

AU - Rasmussen,J. J.

AU - McKnight,Ursula S.

AU - Loinaz,Maria Christina

AU - Thomsen,Nanna Isbak

AU - Olsson,Mikael Emil

AU - Bjerg,Poul Løgstrup

AU - Binning,Philip John

AU - Kronvang,B.

PY - 2013

Y1 - 2013

N2 - Mitigation activities to improve water quality and quantity in streams as well as stream management and restoration efforts are conducted in the European Union aiming to improve the chemical, physical and ecological status of streams. Headwater streams are often characterised by impairment of hydromorphological, chemical, and ecological conditions due to multiple anthropogenic impacts. However, they are generally disregarded as water bodies for mitigation activities in the European Water Framework Directive despite their importance for supporting a higher ecological quality in higher order streams.<br/><br/>We studied 11 headwater streams in the Hove catchment in the Copenhagen region. All sites had substantial physical habitat and water quality impairments due to anthropogenic influence (intensive agriculture, urban settlements, contaminated sites and low base-flow due to water abstraction activities in the catchment). We aimed to identify the dominating anthropogenic stressors at the catchmentscale causing ecological impairment of benthic macroinvertebrate communities and provide a rank-order of importance that could help in prioritising mitigation activities. We identified numerous chemical and hydromorphological impacts of which several were probably causing major ecological impairments, but we were unable to provide a robust rank-ordering of importance suggesting that targeted mitigation efforts on single anthropogenic stressors in the catchment are unlikely to have substantial effects on the ecological quality in these streams.<br/><br/>The SPEcies At Risk (SPEAR) index explained most of the variability in the macroinvertebrate community structure, and notably, SPEAR index scores were often very low (&lt; 10% SPEAR abundance). An extensive re-sampling ofa subset of the streams provided evidence that especially insecticides were probably essential contributors to the overall ecological impairment of these streams.<br/><br/>Our results suggest that headwater streams should be considered in future management and mitigation plans. Catchment-based management is necessary because several anthropogenic stressors exceeded problematic thresholds, suggesting that more holistic approaches should be preferred.

AB - Mitigation activities to improve water quality and quantity in streams as well as stream management and restoration efforts are conducted in the European Union aiming to improve the chemical, physical and ecological status of streams. Headwater streams are often characterised by impairment of hydromorphological, chemical, and ecological conditions due to multiple anthropogenic impacts. However, they are generally disregarded as water bodies for mitigation activities in the European Water Framework Directive despite their importance for supporting a higher ecological quality in higher order streams.<br/><br/>We studied 11 headwater streams in the Hove catchment in the Copenhagen region. All sites had substantial physical habitat and water quality impairments due to anthropogenic influence (intensive agriculture, urban settlements, contaminated sites and low base-flow due to water abstraction activities in the catchment). We aimed to identify the dominating anthropogenic stressors at the catchmentscale causing ecological impairment of benthic macroinvertebrate communities and provide a rank-order of importance that could help in prioritising mitigation activities. We identified numerous chemical and hydromorphological impacts of which several were probably causing major ecological impairments, but we were unable to provide a robust rank-ordering of importance suggesting that targeted mitigation efforts on single anthropogenic stressors in the catchment are unlikely to have substantial effects on the ecological quality in these streams.<br/><br/>The SPEcies At Risk (SPEAR) index explained most of the variability in the macroinvertebrate community structure, and notably, SPEAR index scores were often very low (&lt; 10% SPEAR abundance). An extensive re-sampling ofa subset of the streams provided evidence that especially insecticides were probably essential contributors to the overall ecological impairment of these streams.<br/><br/>Our results suggest that headwater streams should be considered in future management and mitigation plans. Catchment-based management is necessary because several anthropogenic stressors exceeded problematic thresholds, suggesting that more holistic approaches should be preferred.

U2 - 10.1016/j.scitotenv.2012.10.076

DO - 10.1016/j.scitotenv.2012.10.076

M3 - Journal article

VL - 442

SP - 420

EP - 431

JO - Science of the Total Environment

T2 - Science of the Total Environment

JF - Science of the Total Environment

SN - 0048-9697

ER -