Huan Zhang, Yulu Wang, Peiyu Zhang, Lars-Anders Hansson, Jorge García Molinos, Konghao Zhu, Hailu Li, Huan Wang, Hongxia Wang, Yingchun Gong, Liang He, Min Zhang, Jun Xu
Climate warming, nutrient loading, and pesticide pollution are major anthropogenic stressors affecting community dynamics and trophic interactions in aquatic ecosystems. However, the complex interplay among these stressors remains poorly understood as most studies focus on a single stressor and overlook the effects of temporal variations.
To address this knowledge gap, we first conducted a long-term outdoor experiment to examine the effects of climate warming, nutrient loading, and a neonicotinoid pesticide (imidacloprid) on the responses of the common predator–prey pair cyclopoid copepods and rotifers. Additionally, a follow-up laboratory experiment was conducted to assess the dose-dependent impact of imidacloprid on the predation rate of cyclopoid copepods on rotifers, and to explore mechanistic alterations in biotic interactions resulting from predator responses to varying neonicotinoid concentrations.
The neonicotinoid pesticide was the most influential stressor, significantly reducing cyclopoid copepod populations thereby positively affecting rotifer abundances due to a release from predation. Nutrient loading boosted copepod abundances but weakened their top-down control on rotifer prey, disrupting predator–prey dynamics. Warming had negligible effects on copepod abundances, but ultimately increased rotifer abundances.
Warming predominantly influenced rotifer abundances during the establishment phase, whereas the effects of the pesticide became more pronounced during subsequent growth and reproduction phases. Conversely, the neonicotinoid pesticide consistently emerged as the primary stressor impacting cyclopoid copepods throughout the experiment.
Our study underscores the importance of considering temporal dynamics when assessing the combined effects of multiple stressors for understanding responses among interacting organisms and highlights the significance of organism life history stages in their distinct reactions to specific compounded threats over time.
{"title":"Multiple Stressors From Climate Warming, Neonicotinoid Pesticide, and Nutrient Loading Alter Zooplankton Predator–Prey Dynamics in Freshwaters","authors":"Huan Zhang, Yulu Wang, Peiyu Zhang, Lars-Anders Hansson, Jorge García Molinos, Konghao Zhu, Hailu Li, Huan Wang, Hongxia Wang, Yingchun Gong, Liang He, Min Zhang, Jun Xu","doi":"10.1111/fwb.70132","DOIUrl":"https://doi.org/10.1111/fwb.70132","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Climate warming, nutrient loading, and pesticide pollution are major anthropogenic stressors affecting community dynamics and trophic interactions in aquatic ecosystems. However, the complex interplay among these stressors remains poorly understood as most studies focus on a single stressor and overlook the effects of temporal variations.</li>\u0000 \u0000 \u0000 <li>To address this knowledge gap, we first conducted a long-term outdoor experiment to examine the effects of climate warming, nutrient loading, and a neonicotinoid pesticide (imidacloprid) on the responses of the common predator–prey pair cyclopoid copepods and rotifers. Additionally, a follow-up laboratory experiment was conducted to assess the dose-dependent impact of imidacloprid on the predation rate of cyclopoid copepods on rotifers, and to explore mechanistic alterations in biotic interactions resulting from predator responses to varying neonicotinoid concentrations.</li>\u0000 \u0000 \u0000 <li>The neonicotinoid pesticide was the most influential stressor, significantly reducing cyclopoid copepod populations thereby positively affecting rotifer abundances due to a release from predation. Nutrient loading boosted copepod abundances but weakened their top-down control on rotifer prey, disrupting predator–prey dynamics. Warming had negligible effects on copepod abundances, but ultimately increased rotifer abundances.</li>\u0000 \u0000 \u0000 <li>Warming predominantly influenced rotifer abundances during the establishment phase, whereas the effects of the pesticide became more pronounced during subsequent growth and reproduction phases. Conversely, the neonicotinoid pesticide consistently emerged as the primary stressor impacting cyclopoid copepods throughout the experiment.</li>\u0000 \u0000 \u0000 <li>Our study underscores the importance of considering temporal dynamics when assessing the combined effects of multiple stressors for understanding responses among interacting organisms and highlights the significance of organism life history stages in their distinct reactions to specific compounded threats over time.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145572544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Raymond M. Lee, Scott Collins, Erin F. Jones, Gabriella Lawson, Sarah Chan, Rachel L. Wood, Neil Hansen, Benjamin W. Abbott, Gregory T. Carling, Michelle A. Baker, Zachary T. Aanderud
Cyanobacterial proliferation in inland waters can degrade water quality and harm human health. Cyanobacterial proliferation is determined largely by nitrogen and phosphorus supply, though nutrient conditions in the impacted lake or reservoir and its inflow(s) are not always sufficient for explaining/mitigating the bloom. Other factors may include fluvial seeding of cyanobacteria, in-lake sediment release then entrainment of nutrients and species preference for nutrients (e.g., diazotrophic vs. non-diazotrophic).
We studied diverse aquatic systems (drinking water reservoir to throughflow and endorheic lakes along a freshwater to hypersaline gradient) to investigate (a) how nutrients supported cyanobacterial blooms (blooms were defined by the outsized relative abundance of a given cyanobacterial species); (b) which factors besides external nutrient loading supported blooms; and (c) if/how all these processes changed across limnologic conditions in successively downstream systems.
Results showed that blooms occurred in different patterns despite being located in the same basin with the same regional climate. Blooms were controlled by nitrogen at the freshwater reservoir (Phormidium spp. succeeded by Microcystis spp.), phosphorus at the brackish lake (Aphanizomenon flos-aquae) and inflow at the hypersaline endorheic lake (Nodularia spp.). At the reservoir, there were spatial and temporal shifts in dominance from diazotrophic (historically) to non-diazotrophic species (currently) that occurred likely due to successful watershed management of phosphorus loading; at the endorheic lake, the bay dried up completely, likely due to high water consumption, which reduced inflow over time.
Results suggested that bloom characteristics and controls changed at each study lake due to different local human activities, so strategies for nutrient and bloom mitigation should be site-specific rather than uniform for the region.
The concept of a cyanobacterial ‘bloom’ is ambiguous because it can be defined by different thresholds of different specimens (e.g., chlorophyll concentration, cyanobacterial cell count/density, cyanotoxin concentration or perceived/actual harm or risk thereof). Here, we defined a bloom as excessive cyanobacterial relative abundance, which is a novel way to track the life cycles of dominant cyanobacterial species in the context of limnologic and nutrient controls. This approach allowed us to identify significant and different anthropogenic changes to controlling factors of blooms in diverse settings.
{"title":"Anthropogenic Changes to Factors Controlling Cyanobacterial Blooms Along a Chain of Fresh to Hypersaline Water Bodies","authors":"Raymond M. Lee, Scott Collins, Erin F. Jones, Gabriella Lawson, Sarah Chan, Rachel L. Wood, Neil Hansen, Benjamin W. Abbott, Gregory T. Carling, Michelle A. Baker, Zachary T. Aanderud","doi":"10.1111/fwb.70135","DOIUrl":"https://doi.org/10.1111/fwb.70135","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Cyanobacterial proliferation in inland waters can degrade water quality and harm human health. Cyanobacterial proliferation is determined largely by nitrogen and phosphorus supply, though nutrient conditions in the impacted lake or reservoir and its inflow(s) are not always sufficient for explaining/mitigating the bloom. Other factors may include fluvial seeding of cyanobacteria, in-lake sediment release then entrainment of nutrients and species preference for nutrients (e.g., diazotrophic vs. non-diazotrophic).</li>\u0000 \u0000 \u0000 <li>We studied diverse aquatic systems (drinking water reservoir to throughflow and endorheic lakes along a freshwater to hypersaline gradient) to investigate (a) how nutrients supported cyanobacterial blooms (blooms were defined by the outsized relative abundance of a given cyanobacterial species); (b) which factors besides external nutrient loading supported blooms; and (c) if/how all these processes changed across limnologic conditions in successively downstream systems.</li>\u0000 \u0000 \u0000 <li>Results showed that blooms occurred in different patterns despite being located in the same basin with the same regional climate. Blooms were controlled by nitrogen at the freshwater reservoir (<i>Phormidium</i> spp. succeeded by <i>Microcystis</i> spp.), phosphorus at the brackish lake (<i>Aphanizomenon flos-aquae</i>) and inflow at the hypersaline endorheic lake (<i>Nodularia</i> spp.). At the reservoir, there were spatial and temporal shifts in dominance from diazotrophic (historically) to non-diazotrophic species (currently) that occurred likely due to successful watershed management of phosphorus loading; at the endorheic lake, the bay dried up completely, likely due to high water consumption, which reduced inflow over time.</li>\u0000 \u0000 \u0000 <li>Results suggested that bloom characteristics and controls changed at each study lake due to different local human activities, so strategies for nutrient and bloom mitigation should be site-specific rather than uniform for the region.</li>\u0000 \u0000 \u0000 <li>The concept of a cyanobacterial ‘bloom’ is ambiguous because it can be defined by different thresholds of different specimens (e.g., chlorophyll concentration, cyanobacterial cell count/density, cyanotoxin concentration or perceived/actual harm or risk thereof). Here, we defined a bloom as excessive cyanobacterial relative abundance, which is a novel way to track the life cycles of dominant cyanobacterial species in the context of limnologic and nutrient controls. This approach allowed us to identify significant and different anthropogenic changes to controlling factors of blooms in diverse settings.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145572297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bradley J. Pusey, Mark J. Kennard, Leah S. Beesley, Tsz Wai Ho, Aaron M. Davis, Michael M. Douglas
<div> <p> </p><ol> <li>Intact riparian vegetation plays an important role in the energetics of freshwater ecosystems. Plant and animal biomass from the riparian zone may be directly consumed by freshwater organisms without intermediary processing by microbial or metazoan communities. This study examined the extent and importance of such direct consumption by Australian freshwater fishes.</li> <li>We assembled a data set that spanned the Australian continent and examined the extent of terrestrial contributions to freshwater fish diets for 137 species (i.e., approximately one half of Australia's fish fauna). Using a range of multivariate methods we examined variation in reliance on terrestrial material (leaves, fruit, invertebrates and vertebrates) between species and families and between different regions of Australia, particularly focussing on differences between temperate and tropical Australia. We also examined whether particular aspects of morphology were related to increased consumption of terrestrially-derived material.</li> <li>Overall, terrestrial invertebrates contributed 10% or more of the diet of about one quarter of all species and families examined. Most families contained at least one species for which consumption of terrestrial invertebrates was high (> 20%) but only two families, Galaxiidae and Melanotaeniidae, exhibited consistently high consumption across most species. Terrestrial vegetation, principally fruit, contributed 10% or more of the diet in three species from two families only (Terapontidae and Ariidae). There was little regional variation in reliance on terrestrial invertebrates as a food source, but species in south-western Western Australia consistently consumed more than did species elsewhere. Frugivory, in contrast, was significantly more common in the wet-dry tropical northern Australia as reported elsewhere for other tropical regions.</li> <li>Australian freshwater fishes appear to rely more on terrestrial invertebrates than do freshwater fishes elsewhere although data is largely lacking to make broader comparisons with other continents. Morphological correlates with the consumption of terrestrial material were individually and collectively limited, but species with a pelagic habit and an upturned (supraterminal) mouth consumed significantly more such material than did species within other habit/mouth orientation combinations.</li> <li>The present study further confirms the importance of the riparian zone to lotic ecosystem function with direct contributions of terrestrially derived material contributing significantly to the diet of many species and of some families in particular. Although data is lacking for large-scale (i.e., continental) assessments of the importance of terrestrial su
{"title":"Eating In or Out? Terrestrial Contributions to the Diet of Australian Freshwater Fish","authors":"Bradley J. Pusey, Mark J. Kennard, Leah S. Beesley, Tsz Wai Ho, Aaron M. Davis, Michael M. Douglas","doi":"10.1111/fwb.70129","DOIUrl":"https://doi.org/10.1111/fwb.70129","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Intact riparian vegetation plays an important role in the energetics of freshwater ecosystems. Plant and animal biomass from the riparian zone may be directly consumed by freshwater organisms without intermediary processing by microbial or metazoan communities. This study examined the extent and importance of such direct consumption by Australian freshwater fishes.</li>\u0000 \u0000 \u0000 <li>We assembled a data set that spanned the Australian continent and examined the extent of terrestrial contributions to freshwater fish diets for 137 species (i.e., approximately one half of Australia's fish fauna). Using a range of multivariate methods we examined variation in reliance on terrestrial material (leaves, fruit, invertebrates and vertebrates) between species and families and between different regions of Australia, particularly focussing on differences between temperate and tropical Australia. We also examined whether particular aspects of morphology were related to increased consumption of terrestrially-derived material.</li>\u0000 \u0000 \u0000 <li>Overall, terrestrial invertebrates contributed 10% or more of the diet of about one quarter of all species and families examined. Most families contained at least one species for which consumption of terrestrial invertebrates was high (> 20%) but only two families, Galaxiidae and Melanotaeniidae, exhibited consistently high consumption across most species. Terrestrial vegetation, principally fruit, contributed 10% or more of the diet in three species from two families only (Terapontidae and Ariidae). There was little regional variation in reliance on terrestrial invertebrates as a food source, but species in south-western Western Australia consistently consumed more than did species elsewhere. Frugivory, in contrast, was significantly more common in the wet-dry tropical northern Australia as reported elsewhere for other tropical regions.</li>\u0000 \u0000 \u0000 <li>Australian freshwater fishes appear to rely more on terrestrial invertebrates than do freshwater fishes elsewhere although data is largely lacking to make broader comparisons with other continents. Morphological correlates with the consumption of terrestrial material were individually and collectively limited, but species with a pelagic habit and an upturned (supraterminal) mouth consumed significantly more such material than did species within other habit/mouth orientation combinations.</li>\u0000 \u0000 \u0000 <li>The present study further confirms the importance of the riparian zone to lotic ecosystem function with direct contributions of terrestrially derived material contributing significantly to the diet of many species and of some families in particular. Although data is lacking for large-scale (i.e., continental) assessments of the importance of terrestrial su","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145521956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maria Chiara Vulcano, Martin J. Kainz, Georg H. Niedrist, Leopold Füreder
{"title":"The Fundamental Role of Periphyton in Supplying Dietary Energy to Alpine Stream Food Webs: Current Knowledge, Limitations and Future Perspectives","authors":"Maria Chiara Vulcano, Martin J. Kainz, Georg H. Niedrist, Leopold Füreder","doi":"10.1111/fwb.70133","DOIUrl":"https://doi.org/10.1111/fwb.70133","url":null,"abstract":"<p>\u0000 \u0000 </p>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/fwb.70133","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145521957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kexin Zhu, Rong Wang, Bo Qin, Jianan Zheng, Yanjie Zhao, Yu Zhao, Wenxiu Zheng, Jianjun Wang, Xiangdong Yang
Regime shifts in aquatic ecosystems have attracted widespread attention. While research has extensively focused on shallow lakes, such shifts in deep lakes remain less studied. This study investigates the mechanisms influencing regime shifts in Lake Fuxian, China's largest deep freshwater lake, which has experienced cyanobacterial blooms and rapid algal growth despite strict nutrient input regulations.
We examined trends in diatoms, cyanobacteria, and geochemical elements over the past century using rate-of-change analysis, F-statistics and random forest regression models to identify the time of ecological shifts and the factors associated with them.
We found two significant ecological shifts during the 1990s and 2010s. Both were accompanied by increases in TOC, hypolimnetic anoxia and cyanobacterial abundance. The 1990s shift was primarily associated with invasive fish species, whereas the 2010s shift was linked to phosphorus enrichment.
Notably, phosphorus enrichment was not mainly associated with external nutrient inputs but by an internal positive feedback mechanism. Specifically, hypolimnetic anoxia facilitates phosphorus release from sediments, promoting algal growth during mixing periods, which increases oxygen demand. This feedback further alters nutrient dynamics, favouring the proliferation of algal biomass, particularly cyanobacteria, and may ultimately trigger an ecosystem regime shift.
These results suggest that even oligotrophic deep lakes are susceptible to regime shifts, emphasising the importance of disrupting positive feedback mechanisms for effective management.
{"title":"From External Pressure to Internal Drivers: Anthropogenic Disturbance and Positive Feedback Trigger Deep Lake Regime Shifts","authors":"Kexin Zhu, Rong Wang, Bo Qin, Jianan Zheng, Yanjie Zhao, Yu Zhao, Wenxiu Zheng, Jianjun Wang, Xiangdong Yang","doi":"10.1111/fwb.70128","DOIUrl":"https://doi.org/10.1111/fwb.70128","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Regime shifts in aquatic ecosystems have attracted widespread attention. While research has extensively focused on shallow lakes, such shifts in deep lakes remain less studied. This study investigates the mechanisms influencing regime shifts in Lake Fuxian, China's largest deep freshwater lake, which has experienced cyanobacterial blooms and rapid algal growth despite strict nutrient input regulations.</li>\u0000 \u0000 \u0000 <li>We examined trends in diatoms, cyanobacteria, and geochemical elements over the past century using rate-of-change analysis, <i>F</i>-statistics and random forest regression models to identify the time of ecological shifts and the factors associated with them.</li>\u0000 \u0000 \u0000 <li>We found two significant ecological shifts during the 1990s and 2010s. Both were accompanied by increases in TOC, hypolimnetic anoxia and cyanobacterial abundance. The 1990s shift was primarily associated with invasive fish species, whereas the 2010s shift was linked to phosphorus enrichment.</li>\u0000 \u0000 \u0000 <li>Notably, phosphorus enrichment was not mainly associated with external nutrient inputs but by an internal positive feedback mechanism. Specifically, hypolimnetic anoxia facilitates phosphorus release from sediments, promoting algal growth during mixing periods, which increases oxygen demand. This feedback further alters nutrient dynamics, favouring the proliferation of algal biomass, particularly cyanobacteria, and may ultimately trigger an ecosystem regime shift.</li>\u0000 \u0000 \u0000 <li>These results suggest that even oligotrophic deep lakes are susceptible to regime shifts, emphasising the importance of disrupting positive feedback mechanisms for effective management.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145522189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cristina Charette, Mila Rautio, Gilbert Cabana, François Guillemette, Alison M. Derry
{"title":"Cascading Effects of Biological Invasion and Nutriment Enrichment Disrupt Freshwater Trophic Energy Pathways and Food Web Quality","authors":"Cristina Charette, Mila Rautio, Gilbert Cabana, François Guillemette, Alison M. Derry","doi":"10.1111/fwb.70126","DOIUrl":"https://doi.org/10.1111/fwb.70126","url":null,"abstract":"<p>\u0000 \u0000 </p>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/fwb.70126","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145522092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Herbaceous marsh wetlands are widely distributed in northeast China, with huge soil organic carbon storage, playing an important role in the carbon cycle. The microbial communities in their soils are highly sensitive to environmental changes, and their respiration is a major component of wetland carbon cycling. However, there are few studies on the characteristics of soil bacteria in large-scale herbaceous marsh wetlands.
This study employed 16S rRNA sequencing technology to analyse soil bacterial communities in Carex marshes, Phragmites australis marshes and Carex-Deyeuxia angustifolia mixed marshes in Heilongjiang Province, and determined soil microbial respiration (SMR) through laboratory incubation methods. The characteristics and driving factors of soil bacterial communities and SMR were explored using one-way analysis of variance (ANOVA) and correlation analysis.
Our results showed that Proteobacteria and Acidobacteria were dominant in the soils of herbaceous marsh wetlands. The Carex marshes exhibited the highest soil bacterial diversity and soil microbial respiration (SMR), while Phragmites australis marshes showed the lowest. Investigations into driving factors revealed that soil moisture content (MC), pH, and bulk density (BD) significantly influenced bacterial communities, whereas MC and underground biomass (UB) significantly affected SMR. Structural equation modelling (SEM) demonstrated that vegetation types indirectly impact bacterial communities and diversity by regulating soil MC, thereby influencing SMR.
In conclusion, Carex spp.-dominated herbaceous marsh wetlands serve as hotspots for microbially mediated carbon fluxes and play a crucial role in the global carbon cycle. The findings provide empirical support for prioritising such wetlands in climate change mitigation strategies and offer insights into targeted wetland conservation and restoration.
{"title":"Variations in Soil Microbial Community Structure and Respiration Intensity in Different Typical Herbaceous Marsh Wetlands in Northeastern China","authors":"Yuchen Wang, Wenjing Xu, Guocan Zhang, Chen Yang, Li Zhang, Siyan Meng, Linlin Fan, Bing Yu","doi":"10.1111/fwb.70130","DOIUrl":"https://doi.org/10.1111/fwb.70130","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Herbaceous marsh wetlands are widely distributed in northeast China, with huge soil organic carbon storage, playing an important role in the carbon cycle. The microbial communities in their soils are highly sensitive to environmental changes, and their respiration is a major component of wetland carbon cycling. However, there are few studies on the characteristics of soil bacteria in large-scale herbaceous marsh wetlands.</li>\u0000 \u0000 \u0000 <li>This study employed 16S rRNA sequencing technology to analyse soil bacterial communities in Carex marshes, <i>Phragmites australis</i> marshes and Carex-Deyeuxia angustifolia mixed marshes in Heilongjiang Province, and determined soil microbial respiration (SMR) through laboratory incubation methods. The characteristics and driving factors of soil bacterial communities and SMR were explored using one-way analysis of variance (ANOVA) and correlation analysis.</li>\u0000 \u0000 \u0000 <li>Our results showed that Proteobacteria and Acidobacteria were dominant in the soils of herbaceous marsh wetlands. The <i>Carex</i> marshes exhibited the highest soil bacterial diversity and soil microbial respiration (SMR), while <i>Phragmites australis</i> marshes showed the lowest. Investigations into driving factors revealed that soil moisture content (MC), pH, and bulk density (BD) significantly influenced bacterial communities, whereas MC and underground biomass (UB) significantly affected SMR. Structural equation modelling (SEM) demonstrated that vegetation types indirectly impact bacterial communities and diversity by regulating soil MC, thereby influencing SMR.</li>\u0000 \u0000 \u0000 <li>In conclusion, <i>Carex</i> spp.-dominated herbaceous marsh wetlands serve as hotspots for microbially mediated carbon fluxes and play a crucial role in the global carbon cycle. The findings provide empirical support for prioritising such wetlands in climate change mitigation strategies and offer insights into targeted wetland conservation and restoration.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145521880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Flooding is a critical driver of wetland plant growth. However, studies still often consider water depth or submergence duration in isolation. This limits our understanding of how hydrological variation affects plant performance. To address this, we have introduced cumulative emergence height (CEH) as a novel integrative parameter. This is defined as the product of emergence height above the water surface and the duration of emergence and quantifies the combined influence of hydrological exposure on wetland vegetation.
This study aims to evaluate the effectiveness of CEH in predicting biomass accumulation and physiological responses of wetland plants under flood conditions.
We investigated four dominant wetland species (Phragmites australis, Persicaria hydropiper, Phalaris arundinacea and Carex brevicuspis) in the Dongting Lake floodplain under four water levels (−30, 0, 30 and 60 cm) and three time points (45, 90 and 135 days). We measured aboveground and belowground biomass, leaf area, chlorophyll a and b concentration and nitrogen and phosphorus concentration. Partial least squares path modeling (PLS-PM) was used to explore direct and indirect relationships between CEH and plant traits.
Biomass and leaf area were significantly positively correlated with CEH, while chlorophyll and nitrogen concentrations showed negative correlations. CEH promoted biomass accumulation by increasing leaf area and individual number, and by reducing nitrogen and phosphorus concentrations. Species showed contrasting strategies: P. australis and P. hydropiper maintained consistent biomass growth, while P. arundinacea and C. brevicuspis peaked and declined under prolonged submergence.
CEH effectively integrates flood depth and duration into a single, ecologically meaningful parameter. It is a useful predictor of plant growth and physiological responses under dynamic flood conditions in the Dongting Lake wetland. As the study was limited to four species from a single wetland system, the findings apply primarily to similar ecological contexts.
{"title":"Cumulative Emergence Height Dominates Biomass Accumulation From Wetland Species Under Flood Conditions","authors":"Jiacheng Wang, Jiawei Shi, Lianlian Xi, Hui Fu, Guixiang Yuan, Aiping Wu, Yandong Niu, Yonghong Xie, Youzhi Li","doi":"10.1111/fwb.70127","DOIUrl":"https://doi.org/10.1111/fwb.70127","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Flooding is a critical driver of wetland plant growth. However, studies still often consider water depth or submergence duration in isolation. This limits our understanding of how hydrological variation affects plant performance. To address this, we have introduced cumulative emergence height (CEH) as a novel integrative parameter. This is defined as the product of emergence height above the water surface and the duration of emergence and quantifies the combined influence of hydrological exposure on wetland vegetation.</li>\u0000 \u0000 \u0000 <li>This study aims to evaluate the effectiveness of CEH in predicting biomass accumulation and physiological responses of wetland plants under flood conditions.</li>\u0000 \u0000 \u0000 <li>We investigated four dominant wetland species (<i>Phragmites australis</i>, <i>Persicaria hydropiper</i>, <i>Phalaris arundinacea</i> and <i>Carex brevicuspis</i>) in the Dongting Lake floodplain under four water levels (−30, 0, 30 and 60 cm) and three time points (45, 90 and 135 days). We measured aboveground and belowground biomass, leaf area, chlorophyll a and b concentration and nitrogen and phosphorus concentration. Partial least squares path modeling (PLS-PM) was used to explore direct and indirect relationships between CEH and plant traits.</li>\u0000 \u0000 \u0000 <li>Biomass and leaf area were significantly positively correlated with CEH, while chlorophyll and nitrogen concentrations showed negative correlations. CEH promoted biomass accumulation by increasing leaf area and individual number, and by reducing nitrogen and phosphorus concentrations. Species showed contrasting strategies: <i>P. australis</i> and <i>P. hydropiper</i> maintained consistent biomass growth, while <i>P. arundinacea</i> and <i>C. brevicuspis</i> peaked and declined under prolonged submergence.</li>\u0000 \u0000 \u0000 <li>CEH effectively integrates flood depth and duration into a single, ecologically meaningful parameter. It is a useful predictor of plant growth and physiological responses under dynamic flood conditions in the Dongting Lake wetland. As the study was limited to four species from a single wetland system, the findings apply primarily to similar ecological contexts.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145469685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anna Stanicka, Jarosław Kobak, Joanna Hildebrand, Anna Cichy, Kamil Wiśniewski, Daniel Szarmach, Kinga Lesiak, Joanna Urbaniak, Mateusz Augustyniak, Zuzanna Dlouhy, Szymon Graczyk, Arkadiusz Grzeczka, Zuzanna Kowaleska, Monika Lewalska, Katarzyna Lichocka, Sebastian Terebiński, Anna Wiśniewska, Elżbieta Żbikowska, Małgorzata Poznańska-Kakareko
Understanding the impact of invaders and parasites/pathogens and their interactions is desirable in an era of global environmental change. Such comprehensive insight is one of the drivers of sound conservation planning for biodiversity on local and global scales. Bivalves have experienced precipitous declines in species diversity and abundance in recent decades. Few threats have been reported for Sphaeriidae, mainly due to significant data deficiency, particularly at the species level.
We used a vulnerable worldwide fingernail clam Sphaerium rivicola as a model to find multi-species associations between the sphaeriid host, its digenean internal parasites, and fouling invasive dreissenid mussels (including potential interactions among the parasites and foulers). Individual clams were collected from the Włocławek Reservoir (Poland), representing a well-defined and representative population. We analysed host traits—shell length (size), wet weight per unit length (condition) and embryo presence (fertility)—in relation to two biotic stressors: digenean infection and fouling by invasive dreissenid mussels. Our aim was to assess their individual and combined effects on the clam host, and to test for potential interactions between parasites and foulers.
Biofouling and digenean infections had negative effects on clam growth and fertility. The combined presence of both stressors intensified the adverse impact compared to either alone. Tetracotyle metacercariae (recorded in bivalves for the first time) were positively associated with digeneans exploiting clams as first intermediate hosts, but negatively associated with echinostome metacercariae. No evidence was found for parasite dilution or facilitation by dreissenid mussels.
Presumably, the negative consequences for individual clam hosts may affect population-level success metrics. Disseminating the issues raised here will be one of the drivers for considering additional protective measures for endangered clam species.
{"title":"Many Evils Are Worse Than One: An Interplay Between Invasive Biofoulers and Parasites Helps Predict the Future of an Endangered Freshwater Fingernail Clam","authors":"Anna Stanicka, Jarosław Kobak, Joanna Hildebrand, Anna Cichy, Kamil Wiśniewski, Daniel Szarmach, Kinga Lesiak, Joanna Urbaniak, Mateusz Augustyniak, Zuzanna Dlouhy, Szymon Graczyk, Arkadiusz Grzeczka, Zuzanna Kowaleska, Monika Lewalska, Katarzyna Lichocka, Sebastian Terebiński, Anna Wiśniewska, Elżbieta Żbikowska, Małgorzata Poznańska-Kakareko","doi":"10.1111/fwb.70125","DOIUrl":"https://doi.org/10.1111/fwb.70125","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Understanding the impact of invaders and parasites/pathogens and their interactions is desirable in an era of global environmental change. Such comprehensive insight is one of the drivers of sound conservation planning for biodiversity on local and global scales. Bivalves have experienced precipitous declines in species diversity and abundance in recent decades. Few threats have been reported for Sphaeriidae, mainly due to significant data deficiency, particularly at the species level.</li>\u0000 \u0000 \u0000 <li>We used a vulnerable worldwide fingernail clam <i>Sphaerium rivicola</i> as a model to find multi-species associations between the sphaeriid host, its digenean internal parasites, and fouling invasive dreissenid mussels (including potential interactions among the parasites and foulers). Individual clams were collected from the Włocławek Reservoir (Poland), representing a well-defined and representative population. We analysed host traits—shell length (size), wet weight per unit length (condition) and embryo presence (fertility)—in relation to two biotic stressors: digenean infection and fouling by invasive dreissenid mussels. Our aim was to assess their individual and combined effects on the clam host, and to test for potential interactions between parasites and foulers.</li>\u0000 \u0000 \u0000 <li>Biofouling and digenean infections had negative effects on clam growth and fertility. The combined presence of both stressors intensified the adverse impact compared to either alone. Tetracotyle metacercariae (recorded in bivalves for the first time) were positively associated with digeneans exploiting clams as first intermediate hosts, but negatively associated with echinostome metacercariae. No evidence was found for parasite dilution or facilitation by dreissenid mussels.</li>\u0000 \u0000 \u0000 <li>Presumably, the negative consequences for individual clam hosts may affect population-level success metrics. Disseminating the issues raised here will be one of the drivers for considering additional protective measures for endangered clam species.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145469933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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