Details

Autor(en) / Beteiligte

• Leboucher, Thibault
• Mignien, Lucas
• Wach, Marie
• Boutry, Sébastien
• Jamoneau, Aurélien
• Passy, Sophia I.
• Tison-Rosebery, Juliette

Titel

Consideration of mass effect processes in bioindication allows more accurate bioassessment of water quality

Ist Teil von

• Ecological indicators, 2021-08, Vol.127, p.107791, Article 107791

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2021

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• •Bioassessment of ecological status is based on species-environment relationships.•Mass effect influences communities’ structure and blurs these relationships.•A new Diatom Index (IBDmod) was created without species influenced by mass effect.•IBDmod better captures local environmental conditions compared to the original index.•Taking mass effect into account allows more accurate bioassessments of water quality. Bioassessment is widely used to measure ecological integrity of natural habitats following anthropogenic disturbances and modifications. Traditionally, bioassessment has been based exclusively on species-environment interactions, i.e. niche processes. However, dispersal processes, and in particular mass effect, could mask the influence of niche processes and lead to erroneous conclusions about ecosystem health. To circumvent this problem, we identified 40 diatom species with distributions driven primarily by mass effect and propose an alternative version of the Biological Diatom Index (IBD2007) excluding these species. We tested the environmental responses of both the original IBD (IBD2007) and the modified IBD (IBDmod) with a benthic diatom dataset from France, collected between 2007 and 2013 and including 9487 samples from 3913 spatially distinct localities. Our results indicate a better relationship between the IBDmod scores and environmental conditions, compared to the IBD2007 scores, leading to a more accurate determination of river ecological status, especially in conditions of moderate nutrient enrichment. This study supports the idea that mass effect may result in biased evaluation of water quality. It is advocated that this process is considered in other diatom-based indices, and by extension, in any biotic index.