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- Feckler, Alexander, et al.
(författare)
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Cryptic species diversity: an overlooked factor in environmental management?
- 2014
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Ingår i: Journal of Applied Ecology. - : Wiley. - 0021-8901 .- 1365-2664. ; 51, s. 958-967
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Tidskriftsartikel (refereegranskat)abstract
- 1. Molecular genetic methods continuously uncover cryptic lineages harboured by various species. However, from an applied perspective, it remains unclear whether and to which extent such a genetic diversity affects biological traits (e. g. ecological, behavioural and physiological characteristics) and environmental management.2. We assessed potential deviations regarding the trait 'environmental stress tolerance' using individuals from five field populations of each of two cryptic lineages (called A and B) comprised under the nominal species Gammarus fossarum. We used ammonia as a chemical stressor while assessing the feeding rate on leaf discs as a measure of sublethal response. In this context, we established a restriction fragment length polymorphism assay to allow a rapid identification of the lineages.3. We observed a biologically meaningful and statistically significant twofold higher overall tolerance of one cryptic lineage, lineage B, over the other. Confounding factors that may have the potential to influence the test results, such as life stage, sex, season of collection, parasitism, physiological status of organisms and upstream land-use patterns of the river catchments, were either controlled for or displayed only minor deviations between lineages.4. Synthesis and applications. The trait differences observed in the present study seem to be mainly explained by the considerable genetic differentiation between cryptic lineages of one nominal species. Although traits other than tolerance have been minimally investigated in this context, this study indicates implications in the reliability and quality of environmental monitoring and management if cryptic lineage complexes are ignored.
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| 2. |
- Feckler, Alexander, et al.
(författare)
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Inorganic fungicides as routinely applied in organic and conventional agriculture can increase palatability but reduce microbial decomposition of leaf litter
- 2015
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Ingår i: Journal of Applied Ecology. - : Wiley. - 0021-8901 .- 1365-2664. ; 52, s. 310-322
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Tidskriftsartikel (refereegranskat)abstract
- 1. The application of fungicides is considered an indispensable measure to secure crop production. These substances, however, may unintentionally enter surface waters via run-off, potentially affecting the microbial community. To assess such risks adequately, authorities recently called for suitable test designs involving relevant aquatic micro-organisms.2. We assessed the structural and functional responses of leaf-associated microbial communities, which play a key role in the breakdown of allochthonous leaf material in streams, towards the inorganic fungicides copper (Cu) and elemental sulphur (S). These substances are of particular interest as they are authorized for both conventional and organic farming in many countries of the world. We used the food choice of the amphipod shredder Gammarus fossarum (indicative for micro-organism-mediated leaf palatability) as well as microbial leaf decomposition as functional endpoints. Moreover, the leaf-associated microbial communities were characterized by means of bacterial density, fungal biomass and community composition facilitating mechanistic understanding of the observed functional effects.3. While Gammarus preferred Cu-exposed leaves over unexposed ones, microbial leaf decomposition was reduced by both Cu and S (up to 30%). Furthermore, Cu exposure decreased bacterial densities (up to 60%), stimulated the growth of leaf-associated fungi (up to 100%) and altered fungal community composition, while S did not affect any of the assessed structural endpoints.4. Synthesis and applications. We observed both structural and functional changes in leafassociated microbial communities at inorganic fungicide concentrations realistic for surface water bodies influenced by conventional and organic farming. Our data hence justify a careful re-evaluation of the environmental safety of the agricultural use of these compounds. Moreover, inclusion of an experimental design similar to the one used in this study in lower tier environmental risk assessments of antimicrobial compounds may aid to safeguard the integrity of aquatic microbial communities and the functions they provide.
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