Litter breakdown for ecosystem integrity assessment also applies to streams affected by pesticides

While the impact of various anthropogenic alterations, e.g. nutrient enrichment, has been documented on leaf litter breakdown—a key process for stream ecosystems—, our objective was to assess the response of this process to pesticides in agricultural streams. We hypothesized the impairment to be cor...

Full description

Saved in:
Bibliographic Details
Published in:Hydrobiologia 2016-06, Vol.773 (1), p.87-102
Main Authors: Magali, Brosed, Sylvain, Lamothe, Eric, Chauvet
Format: Article
Language:English
Subjects:
Agrochemicals
Anthropogenic factors
Biomedical and Life Sciences
Creeks & streams
Ecology
Ecology, environment
Ecosystem integrity
Ecosystems
Freshwater & Marine Ecology
Fungi
Invertebrates
Leaf litter
Life Sciences
Pesticide toxicity
Pesticides
Primary Research Paper
Stream pollution
Taxa
Zoology
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:While the impact of various anthropogenic alterations, e.g. nutrient enrichment, has been documented on leaf litter breakdown—a key process for stream ecosystems—, our objective was to assess the response of this process to pesticides in agricultural streams. We hypothesized the impairment to be correlated with the pesticides contamination gradient, and the invertebrate decomposers to be more affected than microbial ones. Alder total breakdown rate was found to strongly decrease along the pesticide concentration in 12 French streams, only due to invertebrate-driven breakdown (as determined in coarse-mesh bags) since microbial-driven breakdown (fine-mesh bags) remained unchanged. Coherently, litter-associated shredder taxa richness and abundance together with SPEARₚₑₛₜᵢcᵢdₑ (a specific indicator based on invertebrate traits) were greatly reduced, whereas pesticide toxicity did not affect litter-associated fungal biomass and taxa richness. Consequently, the presence of pesticides compromised leaf breakdown, as microbial decomposers did not compensate for the invertebrate decomposers decline. This occurred while pesticides concentrations even in the most contaminated stream were under the European Union’s Uniform Principles thresholds for targeted species. Our study showed that litter breakdown, particularly the ratio of total to microbial-driven breakdown rate, is a pertinent proxy to assess the functional integrity of pesticide-contaminated streams.
ISSN:0018-8158
1573-5117
DOI:10.1007/s10750-016-2681-2