This is an open access article under the terms of the Creative Commons Attribution-NonCommercial ... more This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
Global change assessments have typically ignored synthetic chemical pollution, despite the rapid ... more Global change assessments have typically ignored synthetic chemical pollution, despite the rapid increase of pharmaceuticals, pesticides, and industrial chemicals in the environment. The paucity of research on the ecological effects of these 'micropollutants' undermines our efforts to address the freshwater biodiversity crisis. Understanding the responses of individual organisms to chemical pollution can help address this knowledge gap because individual-level effects can cascade across populations, communities, and ecosystems with devastating consequences. Inputs of treated municipal wastewater are a major source of micropollutants in receiving environments. Here we assessed population and individual-level influences of treated wastewater on freshwater gammarid amphipods (Gammarus spp.) in Swiss lowland streams in situ and tested effects of a micropollutant mixture on individual G. fossarum using a common garden laboratory experiment. We hypothesised that population-level e...
1. Natural and anthropogenic disturbances commonly alter patterns of biodiversity and ecosystem f... more 1. Natural and anthropogenic disturbances commonly alter patterns of biodiversity and ecosystem functioning. However, how networks of interacting species respond to these changes remains poorly understood. We described aquatic food webs using invertebrate and fish community composition, functional traits, and stable isotopes from twelve agricultural streams along a landscape disturbance gradient. 2. We predicted that excessive deposition of fine inorganic sediment (sedimentation) associated with agricultural activities would negatively influence aquatic trophic diversity (e.g., reduced vertical and horizontal trophic niche breadths). We hypothesized that multiple mechanisms might cause trophic niche 'compression', as indicated by changes in realized trophic roles. 3. Food-web properties based on consumer stable isotope data (δ13C and δ15N) showed that increasing sediment disturbance was associated with reduced trophic diversity. In particular, the aquatic invertebrate commun...
Didymosphenia geminata is a bloom-forming diatom that has invaded numerous temperate rivers globa... more Didymosphenia geminata is a bloom-forming diatom that has invaded numerous temperate rivers globally. Proliferations of D. geminata can result in negative effects on invaded communities. Ecological theory suggests impacts may vary associated with trait variation in both invaded communities and the invader. Trait commonalities related to organism size are rarely considered, yet are expected to influence the outcomes of ecological (niche and neutral) processes and invader effects. We hypothesised that D. geminata would impact diversity and community composition, with effects varying between size classes, influenced by niche and spatial gradients. To examine this hypothesis, we surveyed 55 rivers along a gradient of D. geminata biomass in the South Island, New Zealand, collecting data on algal and invertebrate communities, 33 spatial predictors, and 111 physical and chemical predictors. Didymosphenia geminata biomass was associated with increased species richness in both algal and invertebrate assemblages, but blooms reduced beta-diversity resulting in more homogenous communities. Both niche and neutral processes influenced community assembly and invader effects, which varied between algae and invertebrates. However, D. geminata appeared to have a dominant influence on both communities, irrespective of organism size. These findings reinforce the substantial negative effect invasive species such as D. geminata can cause in invaded ecosystems.
Riparian zones form the interface between stream and terrestrial ecosystems and play a key role t... more Riparian zones form the interface between stream and terrestrial ecosystems and play a key role through their vegetation structure in determining stream biodiversity, ecosystem functioning and regulating human impacts, such as warming, nutrient enrichment and sedimentation. We assessed how differing riparian vegetation types influence the structural and functional composition (based on species traits) of stream invertebrate communities in agricultural catchments. We characterized riparian and stream habitat conditions and sampled stream invertebrate communities in 10 independent site pairs, each comprising one “unbuffered” reach lacking woody riparian vegetation and a second downstream reach with a woody riparian buffer. Forested riparian buffers were associated with greater shading, increased gravel content in stream substrates and faster flow velocities. We detected changes in invertebrate taxonomic composition in response to buffer presence, with an increase in sensitive Ephemero...
Urbanization impacts stream ecosystems globally through degraded water quality, altered hydrology... more Urbanization impacts stream ecosystems globally through degraded water quality, altered hydrology, and landscape disturbances at the catchment and riparian scales, causing biodiversity losses and altered system functioning. Addressing the “urban stream syndrome” requires multiple mitigation tools, and rehabilitation of riparian vegetation may help improve stream ecological status and provide key ecosystem services. However, the extent to which forested riparian buffers can help support stream biodiversity in the face of numerous environmental contingencies remains uncertain. We assessed how a key indicator of stream ecological status, benthic diatoms, respond to riparian habitat conditions using 10 urban site pairs (each comprising of one unbuffered and one buffered reach), and additional urban downstream and forest reference upstream sites in the Oslo Fjord basin. Diatom communities were structured by multiple drivers including spatial location, land use, water quality, and instrea...
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial ... more This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
Global change assessments have typically ignored synthetic chemical pollution, despite the rapid ... more Global change assessments have typically ignored synthetic chemical pollution, despite the rapid increase of pharmaceuticals, pesticides, and industrial chemicals in the environment. The paucity of research on the ecological effects of these 'micropollutants' undermines our efforts to address the freshwater biodiversity crisis. Understanding the responses of individual organisms to chemical pollution can help address this knowledge gap because individual-level effects can cascade across populations, communities, and ecosystems with devastating consequences. Inputs of treated municipal wastewater are a major source of micropollutants in receiving environments. Here we assessed population and individual-level influences of treated wastewater on freshwater gammarid amphipods (Gammarus spp.) in Swiss lowland streams in situ and tested effects of a micropollutant mixture on individual G. fossarum using a common garden laboratory experiment. We hypothesised that population-level e...
1. Natural and anthropogenic disturbances commonly alter patterns of biodiversity and ecosystem f... more 1. Natural and anthropogenic disturbances commonly alter patterns of biodiversity and ecosystem functioning. However, how networks of interacting species respond to these changes remains poorly understood. We described aquatic food webs using invertebrate and fish community composition, functional traits, and stable isotopes from twelve agricultural streams along a landscape disturbance gradient. 2. We predicted that excessive deposition of fine inorganic sediment (sedimentation) associated with agricultural activities would negatively influence aquatic trophic diversity (e.g., reduced vertical and horizontal trophic niche breadths). We hypothesized that multiple mechanisms might cause trophic niche 'compression', as indicated by changes in realized trophic roles. 3. Food-web properties based on consumer stable isotope data (δ13C and δ15N) showed that increasing sediment disturbance was associated with reduced trophic diversity. In particular, the aquatic invertebrate commun...
Didymosphenia geminata is a bloom-forming diatom that has invaded numerous temperate rivers globa... more Didymosphenia geminata is a bloom-forming diatom that has invaded numerous temperate rivers globally. Proliferations of D. geminata can result in negative effects on invaded communities. Ecological theory suggests impacts may vary associated with trait variation in both invaded communities and the invader. Trait commonalities related to organism size are rarely considered, yet are expected to influence the outcomes of ecological (niche and neutral) processes and invader effects. We hypothesised that D. geminata would impact diversity and community composition, with effects varying between size classes, influenced by niche and spatial gradients. To examine this hypothesis, we surveyed 55 rivers along a gradient of D. geminata biomass in the South Island, New Zealand, collecting data on algal and invertebrate communities, 33 spatial predictors, and 111 physical and chemical predictors. Didymosphenia geminata biomass was associated with increased species richness in both algal and invertebrate assemblages, but blooms reduced beta-diversity resulting in more homogenous communities. Both niche and neutral processes influenced community assembly and invader effects, which varied between algae and invertebrates. However, D. geminata appeared to have a dominant influence on both communities, irrespective of organism size. These findings reinforce the substantial negative effect invasive species such as D. geminata can cause in invaded ecosystems.
Riparian zones form the interface between stream and terrestrial ecosystems and play a key role t... more Riparian zones form the interface between stream and terrestrial ecosystems and play a key role through their vegetation structure in determining stream biodiversity, ecosystem functioning and regulating human impacts, such as warming, nutrient enrichment and sedimentation. We assessed how differing riparian vegetation types influence the structural and functional composition (based on species traits) of stream invertebrate communities in agricultural catchments. We characterized riparian and stream habitat conditions and sampled stream invertebrate communities in 10 independent site pairs, each comprising one “unbuffered” reach lacking woody riparian vegetation and a second downstream reach with a woody riparian buffer. Forested riparian buffers were associated with greater shading, increased gravel content in stream substrates and faster flow velocities. We detected changes in invertebrate taxonomic composition in response to buffer presence, with an increase in sensitive Ephemero...
Urbanization impacts stream ecosystems globally through degraded water quality, altered hydrology... more Urbanization impacts stream ecosystems globally through degraded water quality, altered hydrology, and landscape disturbances at the catchment and riparian scales, causing biodiversity losses and altered system functioning. Addressing the “urban stream syndrome” requires multiple mitigation tools, and rehabilitation of riparian vegetation may help improve stream ecological status and provide key ecosystem services. However, the extent to which forested riparian buffers can help support stream biodiversity in the face of numerous environmental contingencies remains uncertain. We assessed how a key indicator of stream ecological status, benthic diatoms, respond to riparian habitat conditions using 10 urban site pairs (each comprising of one unbuffered and one buffered reach), and additional urban downstream and forest reference upstream sites in the Oslo Fjord basin. Diatom communities were structured by multiple drivers including spatial location, land use, water quality, and instrea...
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