8Vineyard areas are important causes of water contamination, especially by pesticides 9 and residues. These compounds can markedly disturb aquatic communities particularly 10 photosynthetic organisms that are targeted by herbicides. Biofilms and diatoms were used as 11 bioindicators for quality assessment in the Morcille watershed, an area impacted by 12Beaujolais vineyards (SE France), during the pesticide spreading period (April-May 2008). 13Biofilms were allowed to settle on glass slides for 4 or 8 weeks at three sites along a 7-km 14 long gradient of trophic (mainly orthophosphate) and pesticide pollution. After a 4-week 15 colonisation, samples from the two contaminated downstream sites were transferred upstream 16 to the clean site for four weeks while others were left in the same place. 17In vivo fluorescence measurements indicated that the periphytic communities were 18 dominated by diatoms. Going downstream, biofilm biomass and diatom species richness 19 decreased; normalized diatom indices (including the French standard BDI) expressed the 20 increase in trophic status quite well. The species composition of the assemblages was used to 21 discriminate between the effects of nutrients and toxicants, which increased simultaneously as 22 the river continued downstream. 23The way in which the biofilm samples transferred upstream recovered was quite 24 different depending on the location of the original site in the contamination gradient. Most of 25 the quantitative descriptors reached a level comparable to that of the reference communities, 26
Manuscript Click here to view linked ReferencesRecovery potential of periphytic communities in a river impacted by a vineyard watershed. Morin, S. etal. 2010. Ecological Indicators, vol. 10, n° 2. p. 419-426. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W87-4X30C60-1&_user=5403746&_rdoc=1&_fmt=&_orig=search&_sort=d&_docan but the diatom assemblages (cell density per surface unit, taxonomic composition) varied 27 between dates and along the gradient. These communities did not entirely recover a reference 28 structure but the increase in diversity, associated with the settlement of sensitive species, 29 suggested an elevated recovery potential. 30 31 Keywords 32 River biofilms; diatoms; pesticides; Biological Diatom Index; community analysis; diuron; 33 recovery 34
35Recovery potential of periphytic communities in a river impacted by a vineyard watershed. Morin, S. etal.
SUMMARY1. Ecology and ecotoxicology have different historical roots, despite their similar names, but are slowly converging to meet the challenge of addressing the massive global proliferation and release of chemicals in the environment. The conceptual, methodological, review and standard research papers in this special issue reflect this emerging trend of blending ecological and ecotoxicological perspectives to assess impacts in freshwater ecosystems. 2. Assessing community and ecosystem impacts of chemical contaminants is complex, however, and will require approaches that explicitly consider biological and chemical diversity as well as the natural variability of environmental factors at multiple spatial and temporal scales. 3. Central themes of the papers in this issue are (i) the importance of indirect effects of chemical contaminants on species interactions and food webs; (ii) effects of multiple stressors, especially interactions between contaminants and environmental factors; (iii) consequences of chemical exposure on ecosystem processes such as primary production and litter decomposition; (iv) the need to account for context dependency and (v) potentially harmful community and ecosystem effects of emerging contaminants, among which nanoparticles are prominently represented. 4. Collectively, these papers show that integrating ecological principles into the design and implementation of ecotoxicological research is essential for assessing and predicting contaminant impacts on biological communities and ecosystems. Conversely, applied ecology and bioassessment would benefit from concepts and approaches developed in ecotoxicology and from fully embracing chemical contaminants as key drivers of community structure and ecosystem processes.
SUMMARY1. A major challenge in environmental risk assessment of pollutants is establishing a causal relationship between field exposure and community effects that integrates both structural and functional complexity within ecosystems. 2. Pollution-induced community tolerance (PICT) is a concept that evaluates whether pollutants have exerted a selection pressure on natural communities. PICT detects whether a pollutant has eliminated sensitive species from a community and thereby increased its tolerance. PICT has the potential to link assessments of the ecological and chemical status of ecosystems by providing causal analysis for effect-based monitoring of impacted field sites. 3. Using PICT measurements and microbial community endpoints in environmental assessment schemes could give more ecological relevance to the tools that are now used in environmental risk assessment. Here, we propose practical guidance and a list of research issues that should be further considered to apply the PICT concept in the field.
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