Fungal composition on leaves explains pollutant-mediated indirect effects on amphipod feeding

Bundschuh, Mirco; Zubrod, Jochen P.; Kosol, Sujitra; Maltby, Lorraine; Stang, Christoph; Duester, Lars; Schulz, Ralf

doi:10.1016/j.aquatox.2011.03.010

Cited by 103 publications

(116 citation statements)

References 42 publications

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“…S7). This is in line with a study of Bundschuh et al [9], that reported no shift in the number of leaf-associated bacterial cells at 50 mg tebuconazole/ L, while fungal biomass reduction was of comparable magnitude to that of the present study. Although differences between treatments in these bulk parameters (abundance and biomass) do not directly indicate shifts in the microbial community, deviations in such parameters may be explained, in part, by differences in the bacterial and fungal species composition.…”

Section: Resultssupporting

confidence: 95%

“…These may cause direct toxic responses in shredders [7], and also may affect the nutritional quality of leaves by altering leaf-associated microbial communities, which potentially affects shredders indirectly [8,9]. However, resulting indirect effects in shredders due to chemical-induced alterations in the conditioning process have not yet been assessed.…”

Section: Introductionmentioning

confidence: 94%

“…Leaf discs were prepared as described in Bundschuh et al [9] with slight alterations. Briefly, black alder leaves (Alnus glutinosa (L.) Gaertn.)…”

Section: Preparation Of Leaf Discsmentioning

confidence: 99%

“…Based on these publications, a tebuconazole concentration of 65 mg/L was chosen for the present study. This concentration was used because shifts in the microbial conditioning of leaf material and hence its nutritional quality [9], but no direct ecotoxicological effects on G. fossarum, were expected [7]. Thus, this concentration was not intended to be environmentally relevant, especially over the long study period.…”

Section: Introductionmentioning

confidence: 99%

“…The triazole tebuconazole was chosen as model fungicide because adverse effects on both parts of the investigated decomposer-detritivore system were already independently displayed [7,9]. Based on these publications, a tebuconazole concentration of 65 mg/L was chosen for the present study.…”

Section: Introductionmentioning

confidence: 99%

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Ecotoxicological impact of the fungicide tebuconazole on an aquatic decomposer‐detritivore system

Zubrod

Bundschuh

Feckler

et al. 2011

Enviro Toxic and Chemistry

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106

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Leaf litter breakdown is a fundamental process in aquatic ecosystems that is realized by microbial decomposers and invertebrate detritivores. Although this process may be adversely affected by fungicides, among other factors, no test design exists to assess combined effects on such decomposer-detritivore systems. Hence, the present study assessed effects of the model fungicide tebuconazole (65 µg/L) on the conditioning of leaf material (by characterizing the associated microbial community) as well as the combined effects (i.e., direct toxicity and food quality-related effects (=indirect)) on the energy processing of the leaf-shredding amphipod Gammarus fossarum using a five-week semistatic test design. Gammarids exposed to tebuconazole produced significantly less feces (≈ 20%), which in turn significantly increased their assimilation (≈ 30%). Moreover, a significantly reduced lipid content (≈ 20%) indicated lower physiological fitness. The conditioning process was altered as well, which was indicated by a significantly reduced fungal biomass (≈ 40%) and sporulation (≈ 30%) associated with the leaf material. These results suggest that tebuconazole affects both components of the investigated decomposer-detritivore system. However, adverse effects on the level of detritivores cannot be explicitly attributed to direct or indirect pathways. Nevertheless, as the endpoints assessed are directly related to leaf litter breakdown and associated energy transfer processes, the protectiveness of environmental risk assessment for this ecosystem function may be more realistically assessed in future studies by using this or comparable test designs.

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Section: Resultssupporting

confidence: 95%

Section: Introductionmentioning

confidence: 94%

“…Leaf discs were prepared as described in Bundschuh et al [9] with slight alterations. Briefly, black alder leaves (Alnus glutinosa (L.) Gaertn.)…”

Section: Preparation Of Leaf Discsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Ecotoxicological impact of the fungicide tebuconazole on an aquatic decomposer‐detritivore system

Zubrod

Bundschuh

Feckler

et al. 2011

Enviro Toxic and Chemistry

Self Cite

106

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Macroinvertebrate identity mediates the effects of litter quality and microbial conditioning on leaf litter recycling in temperate streams

Santonja

Pellan

Piscart

2018

Ecology and Evolution

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Plant litter decomposition is an essential ecosystem function that contributes to carbon and nutrient cycling in streams. Aquatic shredders, mainly macroinvertebrates, can affect this process in various ways; they consume leaf litter, breaking it down into fragments and creating suitable habitats or resources for other organisms through the production of fine particulate organic matter (FPOM). However, measures of litter‐feeding traits across a wide range of aquatic macroinvertebrates are still rare. Here, we assessed the contributions of 11 species of freshwater macroinvertebrates to litter decomposition, by measuring consumption rate, FPOM production, and assimilation rate of highly decomposable (Alnus glutinosa) or poorly decomposable (Quercus robur) leaf litter types. In general, an increase in the quality of litter improved the litter consumption rate, and fungal conditioning of the leaf litter increased both the litter consumption rate and FPOM production. Macroinvertebrates specializing in leaf litter consumption also appeared to be the most sensitive to shifts in litter quality and the conditioning process. Contrary to expectations, the conditioning process did not increase the assimilation of low‐quality litter. There was a strong correlation between the relative consumption rate (RCR) of the two litter types, and the relative FPOM production (RFP) was strongly correlated to the RCR. These findings suggest a consistent relationship between RCR and macroinvertebrate identity that is not affected by litter quality, and that the RFP could be inferred from the RCR. The varying responses of the macroinvertebrate feeding traits to litter quality and the conditioning process suggest that the replacement of a shredder invertebrate species by another species could have major consequences for the decomposition process and the detritus‐based food web in streams. Further studies onto the importance of invertebrate identity and the effects of litter quality in a variety of freshwater ecosystems are needed to understand the whole ecosystem functioning and to predict its response to environmental changes.

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Species turnover and invasion of dominant freshwater invertebrates alter biodiversity–ecosystem‐function relationship

Little

Altermatt

2018

Ecological Monographs

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Freshwater ecosystems rely on allochthonous resources. Integration of these subsidies depends on diversity of both terrestrial resources and aquatic shredder and decomposer communities, but the diversity effects on leaf litter breakdown and decomposition are less clear in aquatic than terrestrial ecosystems. We need a better understanding of this relationship because aquatic communities are rapidly changing with species invasions and anthropogenic impacts. Here, we experimentally disentangled the effects of leaf and shredder richness on leaf litter breakdown by macroinvertebrates in mesocosm experiments using three species of amphipods, a dominant guild of crustaceans in European freshwater ecosystems. Increased leaf richness led to lower‐than‐predicted leaf consumption by native shredders, with mixed evidence of resource‐switching or prioritization of preferred food items within a leaf mix. Higher shredder species richness never promoted leaf consumption rates compared to predictions from relevant single‐species experiments, and instead sometimes substantially decreased leaf consumption. We then conducted a meta‐analysis of leaf litter consumption rates by seven widely distributed amphipod species (the three used in the experiments and four additional species). As expected based on our own experiments, nonnative amphipod species generally had lower biomass‐adjusted leaf litter consumption rates, although their larger body size led to higher per‐individual leaf consumption rates. Contamination of the water by metals, pesticides, and other chemicals additionally significantly decreased leaf litter consumption by multiple native and nonnative species compared to unpolluted systems. While the meta‐analysis suggested that litter consumption, and thus breakdown, would decline if native shredders are replaced by nonnative heterospecifics, complete species replacement is not the only outcome following immigration in a meta‐community context. Our experiments suggest that breakdown rates could remain reasonably high where native species coexist with nonnative arrivals. Experiments that neglect the ecological realism of species coexistence will necessarily mischaracterize effects on ecosystem functioning.

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Fungal composition on leaves explains pollutant-mediated indirect effects on amphipod feeding

Cited by 103 publications

References 42 publications

Ecotoxicological impact of the fungicide tebuconazole on an aquatic decomposer‐detritivore system

Ecotoxicological impact of the fungicide tebuconazole on an aquatic decomposer‐detritivore system

Macroinvertebrate identity mediates the effects of litter quality and microbial conditioning on leaf litter recycling in temperate streams

Species turnover and invasion of dominant freshwater invertebrates alter biodiversity–ecosystem‐function relationship

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