Letha Louisiana Wantania, Jan Möhring, Thore Koppetsch, Friedrich W. Miesen, Daisy Wowor, Farnis Boneka, Fabian Herder
{"title":"Sulawesi Stream Fish Communities Disconnected From the Sea: Absence of Diadromous and Dominance of Exotic Species","authors":"Letha Louisiana Wantania, Jan Möhring, Thore Koppetsch, Friedrich W. Miesen, Daisy Wowor, Farnis Boneka, Fabian Herder","doi":"10.1111/fwb.70143","DOIUrl":"https://doi.org/10.1111/fwb.70143","url":null,"abstract":"<p>\u0000 \u0000 </p>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 12","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/fwb.70143","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145618886","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}
{"title":"Zooplankton Epibionts in Boreal Lakes: Associations With DOC and Host Community Traits","authors":"Satu Estlander, Jukka Horppila","doi":"10.1111/fwb.70146","DOIUrl":"https://doi.org/10.1111/fwb.70146","url":null,"abstract":"<p>\u0000 \u0000 </p>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 12","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/fwb.70146","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145601208","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}
{"title":"Issue Information - Cover and Ed Board","authors":"","doi":"10.1111/fwb.14286","DOIUrl":"https://doi.org/10.1111/fwb.14286","url":null,"abstract":"","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 12","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/fwb.14286","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145601207","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}
Freya E. Rowland, Michael J. Vanni, Nicole M. Hayes, Clifford E. Kraft
Although nitrogen and phosphorus deficiency of algal blooms have been the focus of substantial attention, organic nutrients can limit algal growth in aquatic systems. Growing evidence indicates thiamine (vitamin B1) can influence the community of primary producers in marine systems, but comparatively little is known about the effect of thiamine on freshwater algal productivity.
We conducted 106 nutrient deficiency experiments with water from 39 Ohio lakes of varying trophic status during the growing seasons (April–October) of 2008–2009. Specifically, we tested the response of phytoplankton biomass (as chlorophyll a, chl-a) relative to controls to added nitrogen (N), phosphorus (P), thiamine (Th), or combinations of N + P and N + P + Th. Next, we compared the chl-a growth response of treatment/control to published thresholds based on frequentist approaches and compared the conclusions with Bayesian model results that focused on probability of a response.
Although N + P addition was consistently associated with the largest chl-a response, we found evidence of a thiamine influence on phytoplankton growth in some experiments. The Bayesian approach suggested thiamine may become more limiting as the growing season progresses. By late in the growing season, there was an 85% probability of a positive algal growth response to thiamine addition.
Understanding the role of thiamine or other overlooked nutrients is not likely to alter the prevailing understanding of nutrient deficiency in freshwater ecosystems. However, we present evidence that freshwater phytoplankton may experience thiamine deficiency and suggest limnologists consider thiamine when exploring resource deficiencies.
{"title":"Potential Thiamine Deficiency of Phytoplankton Across a Productivity Gradient and Seasons in Ohio Lakes","authors":"Freya E. Rowland, Michael J. Vanni, Nicole M. Hayes, Clifford E. Kraft","doi":"10.1111/fwb.70134","DOIUrl":"https://doi.org/10.1111/fwb.70134","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Although nitrogen and phosphorus deficiency of algal blooms have been the focus of substantial attention, organic nutrients can limit algal growth in aquatic systems. Growing evidence indicates thiamine (vitamin B<sub>1</sub>) can influence the community of primary producers in marine systems, but comparatively little is known about the effect of thiamine on freshwater algal productivity.</li>\u0000 \u0000 \u0000 <li>We conducted 106 nutrient deficiency experiments with water from 39 Ohio lakes of varying trophic status during the growing seasons (April–October) of 2008–2009. Specifically, we tested the response of phytoplankton biomass (as chlorophyll <i>a</i>, chl-<i>a</i>) relative to controls to added nitrogen (N), phosphorus (P), thiamine (Th), or combinations of N + P and N + P + Th. Next, we compared the chl-<i>a</i> growth response of treatment/control to published thresholds based on frequentist approaches and compared the conclusions with Bayesian model results that focused on probability of a response.</li>\u0000 \u0000 \u0000 <li>Although N + P addition was consistently associated with the largest chl-<i>a</i> response, we found evidence of a thiamine influence on phytoplankton growth in some experiments. The Bayesian approach suggested thiamine may become more limiting as the growing season progresses. By late in the growing season, there was an 85% probability of a positive algal growth response to thiamine addition.</li>\u0000 \u0000 \u0000 <li>Understanding the role of thiamine or other overlooked nutrients is not likely to alter the prevailing understanding of nutrient deficiency in freshwater ecosystems. However, we present evidence that freshwater phytoplankton may experience thiamine deficiency and suggest limnologists consider thiamine when exploring resource deficiencies.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145619136","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}
Jeffrey R. Baldock, Robert Al-Chokhachy, Annika Walters
<div> <p> </p><ol> <li>Landscapes are composed of habitat patches and conditions that vary across space and time. While habitat variability and complexity can support important ecological processes and ecosystem services, the dynamic nature of habitats can also constrain organismal growth and production as optimal conditions are fleeting. In riverine ecosystems, groundwater discharge to streams stabilises water temperature and flow regimes, thus mediating how habitat complexity is expressed. Yet, how stable habitats structure growth and production within the broader landscape matrix is not well understood.</li> <li>In this study, we explored the effects of groundwater on spatiotemporal variation in growth and production for juvenile Yellowstone cutthroat trout (<i>Oncorhynchus virginalis bouvieri</i>) across the upper Snake River catchment, Wyoming, USA. We combined machine learning techniques and remotely sensed landscape data to estimate groundwater availability across the river network, which we linked to stream temperature regimes and conspecific density. We then used Bayesian hierarchical models to quantify the effects of temperature, density and groundwater on spatiotemporal variation in fish growth and production in 52 focal reaches. Finally, we predicted body size trajectories and trends in total production continuously over both space and time to understand the effect of groundwater at the riverscape scale.</li> <li>Groundwater discharged to streams where topography changes abruptly in valley-bottom areas underlain by coarse glacial deposits. Groundwater stabilised temperature regimes and was associated with high trout densities. Temperature and density, in turn, interacted to influence growth rates: growth increased strongly with temperature, but this effect was reduced when density was high. Accordingly, variation in groundwater availability among stream reaches diversified growth and production regimes. In reaches with low groundwater availability, growth and production declined over time from summer maxima. In contrast, in reaches with high groundwater availability, temporal trends in growth and production were hump-shaped—peaking in autumn—and mean production was greater. At the riverscape scale, temporal asynchrony in growth rates generated convergent spatial variation in growth capacity, but—when combined with density—led to the formation of distinct hotspots of production.</li> <li>Our results demonstrate how groundwater, an important driver of aquatic ecosystem heterogeneity, structures trout growth and production across space and time. Importantly, rare, but stable habitats may disproportionately affect ecological processes and serve as key sources of population diversity at larger spatial scales.</li> </ol> </
{"title":"Groundwater Structures Fish Growth and Production Across a Riverscape","authors":"Jeffrey R. Baldock, Robert Al-Chokhachy, Annika Walters","doi":"10.1111/fwb.70112","DOIUrl":"https://doi.org/10.1111/fwb.70112","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Landscapes are composed of habitat patches and conditions that vary across space and time. While habitat variability and complexity can support important ecological processes and ecosystem services, the dynamic nature of habitats can also constrain organismal growth and production as optimal conditions are fleeting. In riverine ecosystems, groundwater discharge to streams stabilises water temperature and flow regimes, thus mediating how habitat complexity is expressed. Yet, how stable habitats structure growth and production within the broader landscape matrix is not well understood.</li>\u0000 \u0000 \u0000 <li>In this study, we explored the effects of groundwater on spatiotemporal variation in growth and production for juvenile Yellowstone cutthroat trout (<i>Oncorhynchus virginalis bouvieri</i>) across the upper Snake River catchment, Wyoming, USA. We combined machine learning techniques and remotely sensed landscape data to estimate groundwater availability across the river network, which we linked to stream temperature regimes and conspecific density. We then used Bayesian hierarchical models to quantify the effects of temperature, density and groundwater on spatiotemporal variation in fish growth and production in 52 focal reaches. Finally, we predicted body size trajectories and trends in total production continuously over both space and time to understand the effect of groundwater at the riverscape scale.</li>\u0000 \u0000 \u0000 <li>Groundwater discharged to streams where topography changes abruptly in valley-bottom areas underlain by coarse glacial deposits. Groundwater stabilised temperature regimes and was associated with high trout densities. Temperature and density, in turn, interacted to influence growth rates: growth increased strongly with temperature, but this effect was reduced when density was high. Accordingly, variation in groundwater availability among stream reaches diversified growth and production regimes. In reaches with low groundwater availability, growth and production declined over time from summer maxima. In contrast, in reaches with high groundwater availability, temporal trends in growth and production were hump-shaped—peaking in autumn—and mean production was greater. At the riverscape scale, temporal asynchrony in growth rates generated convergent spatial variation in growth capacity, but—when combined with density—led to the formation of distinct hotspots of production.</li>\u0000 \u0000 \u0000 <li>Our results demonstrate how groundwater, an important driver of aquatic ecosystem heterogeneity, structures trout growth and production across space and time. Importantly, rare, but stable habitats may disproportionately affect ecological processes and serve as key sources of population diversity at larger spatial scales.</li>\u0000 </ol>\u0000 \u0000 </","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145626022","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}
Martin Berggren, Mayra P. D. Rulli, Ann-Kristin Bergström, Ryan A. Sponseller, Geert Hensgens
{"title":"Does Dissolved Organic Matter Composition Help Explain the Concentrations of Bioavailable Macronutrients in Organic Matter-Rich Freshwaters?","authors":"Martin Berggren, Mayra P. D. Rulli, Ann-Kristin Bergström, Ryan A. Sponseller, Geert Hensgens","doi":"10.1111/fwb.70141","DOIUrl":"https://doi.org/10.1111/fwb.70141","url":null,"abstract":"<p>\u0000 \u0000 </p>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/fwb.70141","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145619059","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}
{"title":"Cyanobacterial Bloom Development, Nitrogen Fixation and Community Change: Insights on Rapid Change From a Shallow Lake","authors":"Lisa M. Boyer, Scott N. Higgins, Helen M. Baulch","doi":"10.1111/fwb.70131","DOIUrl":"https://doi.org/10.1111/fwb.70131","url":null,"abstract":"<p>\u0000 \u0000 </p>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/fwb.70131","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145572604","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}
Chao Guo, Wei Li, Adam G. Hansen, Shiqi Li, Jie Ke, Erik Jeppesen, Chuansong Liao, Jing Yuan, Tanglin Zhang, Chuanbo Guo, Jiashou Liu
The proliferation of small-bodied fishes and their foraging effects within food webs can limit the growth of submerged macrophytes and degrade water quality in shallow lake ecosystems. The foraging habits of small-bodied fishes vary, and, therefore, ecosystem responses may differ depending on which species or feeding guild that dominates the fish community. Yet, species and feeding guild-specific foraging effects remain poorly understood.
Here, we used an experimental mesocosm to evaluate how water quality and submerged macrophytes respond to different species of small-bodied fishes, including omnivorous bitterling Acheilognathus macropterus (AMA), crucian carp Carassius auratus (CAU), sharpbelly Hemiculter leucisculus (HLE), zooplanktivorous thin sharpbelly Toxabramis swinhonis (TSW) and their mixes (1:1:1:1) (MIX).
Our results showed that the mean weekly total nitrogen, total phosphorus, turbidity, chlorophyll-a and trophic level index values were significantly higher in treatments with fish compared to fish-free controls during the experiment. At the end of the experiment, mean values for the number of submerged macrophyte shoots, leaf number, dry mass and the relative growth rate of shoots were significantly lower in the treatments with than without fish. In addition, mean values for leaf height, leaf width and the dry mass of submerged macrophytes in the TSW treatment were significantly greater than in the CAU, HLE and AMA treatments. Structural equation modelling revealed that small-bodied omnivorous fishes (i.e., crucian carp, sharpbelly and bitterling) affected submerged macrophyte growth more than zooplanktivorous fishes (i.e., thin sharpbelly), driven by their different foraging habits.
Our findings indicated that high abundances of small-bodied fishes have negative effects on water quality and the growth of submerged macrophytes in subtropical shallow lake ecosystems, but the effects differed with fish foraging guild. Control of overabundant small-bodied fishes (especially omnivorous fishes) may facilitate maintenance or effective restoration of submerged macrophytes and subtropical shallow lake ecosystem structure and function.
{"title":"Diverse Foraging in Small-Bodied Fishes: Effects on Water Quality and Submerged Macrophytes in Shallow Subtropical Lake Ecosystems","authors":"Chao Guo, Wei Li, Adam G. Hansen, Shiqi Li, Jie Ke, Erik Jeppesen, Chuansong Liao, Jing Yuan, Tanglin Zhang, Chuanbo Guo, Jiashou Liu","doi":"10.1111/fwb.70136","DOIUrl":"https://doi.org/10.1111/fwb.70136","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>The proliferation of small-bodied fishes and their foraging effects within food webs can limit the growth of submerged macrophytes and degrade water quality in shallow lake ecosystems. The foraging habits of small-bodied fishes vary, and, therefore, ecosystem responses may differ depending on which species or feeding guild that dominates the fish community. Yet, species and feeding guild-specific foraging effects remain poorly understood.</li>\u0000 \u0000 \u0000 <li>Here, we used an experimental mesocosm to evaluate how water quality and submerged macrophytes respond to different species of small-bodied fishes, including omnivorous bitterling <i>Acheilognathus macropterus</i> (AMA), crucian carp <i>Carassius auratus</i> (CAU), sharpbelly <i>Hemiculter leucisculus</i> (HLE), zooplanktivorous thin sharpbelly <i>Toxabramis swinhonis</i> (TSW) and their mixes (1:1:1:1) (MIX).</li>\u0000 \u0000 \u0000 <li>Our results showed that the mean weekly total nitrogen, total phosphorus, turbidity, chlorophyll-<i>a</i> and trophic level index values were significantly higher in treatments with fish compared to fish-free controls during the experiment. At the end of the experiment, mean values for the number of submerged macrophyte shoots, leaf number, dry mass and the relative growth rate of shoots were significantly lower in the treatments with than without fish. In addition, mean values for leaf height, leaf width and the dry mass of submerged macrophytes in the TSW treatment were significantly greater than in the CAU, HLE and AMA treatments. Structural equation modelling revealed that small-bodied omnivorous fishes (i.e., crucian carp, sharpbelly and bitterling) affected submerged macrophyte growth more than zooplanktivorous fishes (i.e., thin sharpbelly), driven by their different foraging habits.</li>\u0000 \u0000 \u0000 <li>Our findings indicated that high abundances of small-bodied fishes have negative effects on water quality and the growth of submerged macrophytes in subtropical shallow lake ecosystems, but the effects differed with fish foraging guild. Control of overabundant small-bodied fishes (especially omnivorous fishes) may facilitate maintenance or effective restoration of submerged macrophytes and subtropical shallow lake ecosystem structure and function.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145572605","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}
David J. Gallagher, Payton E. Johnson, Sara M. Kangas, Dylan J. McNulty, Mary A. Thelen, Brian R. Herwig, David F. Staples, Kyle D. Zimmer
Larger trophic niches may contribute to the adaptive capacity of food webs by facilitating shifts in resource use during environmental change, but niche size patterns across lakes and fish species remain poorly known.
We sampled 14 fish species across 17 Minnesota lakes and used stable isotopes ẟ13C (littoral carbon use, hereafter littoral C) and ẟ15N (trophic position) to estimate isotopic niche size (SEAb) for each species in each lake. We tested for relationships between niche size and lake characteristics using common species. We also tested whether niche size differed among and within species and evaluated whether differences could be explained by trophic (e.g., trophic position, littoral C use) or morphological (e.g., total length, length range) variables.
Results showed mean niche size varied four-fold among lakes and was inversely related to lake surface area, total phosphorus, and hypoxic depth. Niches were smaller in larger, more productive lakes with more suitable dissolved oxygen due to reduced littoral C use variation, indicating fish populations focus on more similar habitats along these gradients. Niche size varied over three-fold among species. Niches were largest in bluegill (Lepomis macrochirus) and yellow perch (Perca flavescens) and smallest in walleye (Sander vitreus) and three prey fish species. Niche size showed dome-shaped quadratic relationships with length, trophic position, and littoral C across all populations, but species identity explained more variation. Length range had a positive effect on niche size within all species.
Niche size and potential flexibility in resource use is greatest in small, unproductive lakes with more extensive hypoxic conditions, in species with intermediate trophic positions, and in populations with large length ranges. These results suggest populations contribute differently to the adaptive capacity of food webs depending on lake, trophic, and morphological characteristics.
Overall, our study demonstrates how niche size changes predictably across lakes and species, an important step for understanding lake food web dynamics and managing fish populations.
{"title":"Variables Associated With Isotopic Niche Size in Fish Communities Across North-Temperate Lakes","authors":"David J. Gallagher, Payton E. Johnson, Sara M. Kangas, Dylan J. McNulty, Mary A. Thelen, Brian R. Herwig, David F. Staples, Kyle D. Zimmer","doi":"10.1111/fwb.70142","DOIUrl":"https://doi.org/10.1111/fwb.70142","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Larger trophic niches may contribute to the adaptive capacity of food webs by facilitating shifts in resource use during environmental change, but niche size patterns across lakes and fish species remain poorly known.</li>\u0000 \u0000 \u0000 <li>We sampled 14 fish species across 17 Minnesota lakes and used stable isotopes ẟ<sup>13</sup>C (littoral carbon use, hereafter littoral C) and ẟ<sup>15</sup>N (trophic position) to estimate isotopic niche size (SEA<sub>b</sub>) for each species in each lake. We tested for relationships between niche size and lake characteristics using common species. We also tested whether niche size differed among and within species and evaluated whether differences could be explained by trophic (e.g., trophic position, littoral C use) or morphological (e.g., total length, length range) variables.</li>\u0000 \u0000 \u0000 <li>Results showed mean niche size varied four-fold among lakes and was inversely related to lake surface area, total phosphorus, and hypoxic depth. Niches were smaller in larger, more productive lakes with more suitable dissolved oxygen due to reduced littoral C use variation, indicating fish populations focus on more similar habitats along these gradients. Niche size varied over three-fold among species. Niches were largest in bluegill (<i>Lepomis macrochirus</i>) and yellow perch (<i>Perca flavescens</i>) and smallest in walleye (<i>Sander vitreus</i>) and three prey fish species. Niche size showed dome-shaped quadratic relationships with length, trophic position, and littoral C across all populations, but species identity explained more variation. Length range had a positive effect on niche size within all species.</li>\u0000 \u0000 \u0000 <li>Niche size and potential flexibility in resource use is greatest in small, unproductive lakes with more extensive hypoxic conditions, in species with intermediate trophic positions, and in populations with large length ranges. These results suggest populations contribute differently to the adaptive capacity of food webs depending on lake, trophic, and morphological characteristics.</li>\u0000 \u0000 \u0000 <li>Overall, our study demonstrates how niche size changes predictably across lakes and species, an important step for understanding lake food web dynamics and managing fish populations.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145581196","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}
Yao Zhang, Qingji Zhang, Xiaolong Wang, Zhiqiang Tan, Jinqiao Mao, Yongjiu Cai
<div> <p> </p><ol> <li>Molluscs are a vital component of floodplain wetland ecosystems worldwide, playing key roles in water purification and nutrient cycling. However, the increasing frequency and intensity of global droughts, particularly flash drought (FD) events, have led to widespread mollusc mortality. <i>Bellamya aeruginosa</i>, a dominant freshwater mollusc, has demonstrated remarkable tolerance to extreme drought (ED) conditions. Yet, the underlying mechanisms enabling drought resilience remain unclear. To bridge this gap, we combined field surveys with controlled indoor simulation experiments to assess changes in the density and biomass of <i>B. aeruginosa</i> before and after ED (Pre-ED and Post-ED), and to explore its molecular responses to drought stress.</li> <li>At the population level, no surviving individuals were found on the soil surface during the ED phase. However, as rewetting duration increased, the density and biomass of <i>B. aeruginosa</i> gradually rose and eventually recovered to pre-ED levels. Laboratory experiments revealed that <i>B. aeruginosa</i> crawls into moist, shaded crevices during extreme drought, entering a dormant state by burrowing upside down with its operculum facing upward to endure harsh aridity. During the rewetting phase, its ovoviviparous reproductive strategy enables rapid population recovery.</li> <li>At the molecular level, drought stress led to a statistically significant change in biochemical parameters. Glycogen and protein contents, along with lactate dehydrogenase activity (LDH), were significantly elevated, whereas triglycerides (TG) and antioxidant parameters declined markedly in both the normal drought (ND) and ED groups during drought stress.</li> <li>Metabolomic analyses revealed that combined hypoxia and desiccation stress induced substantial shifts in metabolic pathways. Notably, metabolites involved in glycolysis, fatty acid metabolism and the tricarboxylic acid (TCA) cycle were significantly affected. Key metabolites, including Pyruvaldehyde, Carnitine, Arginine, Histidine, Sphingosine, Ile-Pro and Acetylcholine, were downregulated, while Malate and Pantothenol were upregulated. Furthermore, metabolites related to nucleotide metabolism, such as Inosine, 2′-deoxycytidine 5′-monophosphate, Pseudouridine and Uracil, showed consistent downregulation with increasing drought severity.</li> <li>Overall, <i>B. aeruginosa</i> employs a combination of behavioural strategies, physiological adaptations and rapid reproductive capabilities to endure and recover from extreme drought, thereby enhancing the resistance and resilience of floodplain wetland ecosystems. These findings highlight the importance of conserving microhabitats with residual moisture and offer a scient
{"title":"How Does a Freshwater Snail (Bellamya aeruginosa) Tolerate Extreme Drought in Floodplain Wetlands? Insights From Field Surveys, Biochemical Indicators and Metabolomics","authors":"Yao Zhang, Qingji Zhang, Xiaolong Wang, Zhiqiang Tan, Jinqiao Mao, Yongjiu Cai","doi":"10.1111/fwb.70138","DOIUrl":"https://doi.org/10.1111/fwb.70138","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Molluscs are a vital component of floodplain wetland ecosystems worldwide, playing key roles in water purification and nutrient cycling. However, the increasing frequency and intensity of global droughts, particularly flash drought (FD) events, have led to widespread mollusc mortality. <i>Bellamya aeruginosa</i>, a dominant freshwater mollusc, has demonstrated remarkable tolerance to extreme drought (ED) conditions. Yet, the underlying mechanisms enabling drought resilience remain unclear. To bridge this gap, we combined field surveys with controlled indoor simulation experiments to assess changes in the density and biomass of <i>B. aeruginosa</i> before and after ED (Pre-ED and Post-ED), and to explore its molecular responses to drought stress.</li>\u0000 \u0000 \u0000 <li>At the population level, no surviving individuals were found on the soil surface during the ED phase. However, as rewetting duration increased, the density and biomass of <i>B. aeruginosa</i> gradually rose and eventually recovered to pre-ED levels. Laboratory experiments revealed that <i>B. aeruginosa</i> crawls into moist, shaded crevices during extreme drought, entering a dormant state by burrowing upside down with its operculum facing upward to endure harsh aridity. During the rewetting phase, its ovoviviparous reproductive strategy enables rapid population recovery.</li>\u0000 \u0000 \u0000 <li>At the molecular level, drought stress led to a statistically significant change in biochemical parameters. Glycogen and protein contents, along with lactate dehydrogenase activity (LDH), were significantly elevated, whereas triglycerides (TG) and antioxidant parameters declined markedly in both the normal drought (ND) and ED groups during drought stress.</li>\u0000 \u0000 \u0000 <li>Metabolomic analyses revealed that combined hypoxia and desiccation stress induced substantial shifts in metabolic pathways. Notably, metabolites involved in glycolysis, fatty acid metabolism and the tricarboxylic acid (TCA) cycle were significantly affected. Key metabolites, including Pyruvaldehyde, Carnitine, Arginine, Histidine, Sphingosine, Ile-Pro and Acetylcholine, were downregulated, while Malate and Pantothenol were upregulated. Furthermore, metabolites related to nucleotide metabolism, such as Inosine, 2′-deoxycytidine 5′-monophosphate, Pseudouridine and Uracil, showed consistent downregulation with increasing drought severity.</li>\u0000 \u0000 \u0000 <li>Overall, <i>B. aeruginosa</i> employs a combination of behavioural strategies, physiological adaptations and rapid reproductive capabilities to endure and recover from extreme drought, thereby enhancing the resistance and resilience of floodplain wetland ecosystems. These findings highlight the importance of conserving microhabitats with residual moisture and offer a scient","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":"145572546","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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