Mentum deformities in chironomids have been commonly used as indicators of metal contamination in freshwater ecosystems.Incidence of these deformities suggests sublethal effects and can provide early signals of enviro...
详细信息
Mentum deformities in chironomids have been commonly used as indicators of metal contamination in freshwater ecosystems.Incidence of these deformities suggests sublethal effects and can provide early signals of environmental deterioration.While anthropogenic metal pollution is known to lead to an increase in deformities in chironomids,natural background deformity incidence information is key to their effective use as biomonitoring tools.Here we explore the incidence of deformities from 5000 Tanytarsus(Diptera,Chironomidae)menta in relation to water physicochemical,and sediment metal(Al,As,Cu,Fe,Mn,Pb,Zn)concentration data from numerous sites in the naturally metal-rich Sonora River(NW Mexico)obtained over a two-year period.Higher metal concentrations were found in the upper basin.Higher salinity,total suspended solids and conductivity were found in the lower basin.Only As and Cu were occasionally found above published threshold effect levels(TEL).The proportion of deformities(%D)was low(2.1%)and a generalized linear model only explained 25.36%of%D variability among samples;this model included several physicochemical parameters.The only metal significantly related to deformities was Cu.Despite significant spatial and temporal variability in all metal concentrations and other physicochemical parameters in the basin,we were unable to explain a strong relationship between metal concentration and deformity incidence.Our results,based on consistent%D quantification from 5000 samples from a single taxon,suggest that natural variation in metal concentrations,even when statistically significant,is not associated with notable variations in the incidence of deformities.
Freshwater biota are more comprehensive and direct indicators of biological impacts,and more meaningful to the public than water quality or physical habitat surrogates.Freshwater biotic data and the multiple biologica...
详细信息
Freshwater biota are more comprehensive and direct indicators of biological impacts,and more meaningful to the public than water quality or physical habitat surrogates.Freshwater biotic data and the multiple biological indicators developed from them offer a much richer array of data for assessing the impacts of pollution controls than a limited set of physical or chemical measures.In recent decades,assemblage-based assessments by ecologists,environmental scientists,and water quality agencies have been employed globally for determining the condition of,and threats to,freshwater ecosystems.A key step in this advance has been the development of multimetric indices(MMIs)or indices of biotic integrity(IBIs)based on quantitative assessments of algae,macrophyte,macroinvertebrate,fish or riparian bird assemblages.In Europe,where biological assemblages are mandated for assessing freshwater ecosystem health,many indices are multimetric.However,the proliferation of MMIs globally has not always occurred through the application of rigorous study designs and monitoring protocols,nor have they always effectively incorporated functional metrics,stressor assessments,and statistical analyses.Therefore,in this review,we discuss eleven major concerns with the development and application(including logistical limitations)of multimetric indicators based on freshwater biota to encourage more rigorous and widely applicable(transferable)MMI use and implementation.Specifically,our concerns focus on reference conditions;sampling effort,methods,and season;trophic guild definition;metric comprehensiveness,options,screening and scoring;and MMI validation.MMIs could also benefit from increased attention to ecological mechanisms and metric development,to further improve our understanding of anthropogenic impacts as well as rehabilitation effects on freshwater ecosystems globally.Paying closer attention to study designs,ecological mechanisms and metric development should further improve our understanding of anthropogenic impacts and better facili
暂无评论