Lucas Pereira-Moura, Carolina Gomes Viana, Lucas Ferreira Colares, Karina Dias da Silva, Everton Cruz da Silva, Myckey Kenzy Silva Gonçalves, Lenize Batista Calvão, José Max Barbosa Oliveira-Junior, Leandro Juen, Sheyla Regina Marques Couceiro
Extinction processes driven by habitat loss at multiple scales can lead to changes in the taxonomic and functional rarity of biological communities. However, evidence on the direction of these changes remains limited, making more accurate extrapolations about ecosystem functioning difficult. Therefore, our objective was to assess how rarity, functional groups, and species traits of adult Odonata communities change across extinction scenarios at local and regional scales. We tested the following hypotheses: (i) Functional rarity will decrease as species vulnerable to habitat loss go extinct at local and regional scales; (ii) the average body size of adult Odonata will increase as vulnerable species are lost at local and regional scales; and (iii) the loss of functional groups will occur earlier if the species more vulnerable to habitat loss go extinct, because these species are expected to perform unique ecological roles that may vanish with their disappearance.
We sampled a total of 128 streams in the Eastern Amazon, recording 4031 individuals representing 42 genera and 141 species. After determining the extinction risk and functional rarity of the community, we simulated three extinction scenarios at both local and regional scales (1—extinction of species more vulnerable to habitat loss, 2—extinction of species more tolerant to habitat loss, and 3—random extinction), calculated our response variables, and tested the observed differences using a nonparametric Friedman test.
Our results indicated that communities at local and regional scales tend to lose functional rarity as species vulnerable to habitat loss become extinct, supporting H1. At the local scale, average body size decreased as species more vulnerable to habitat loss became extinct, and at the regional scale, the opposite occurred; that is, there was an increase in average body size as they became extinct, partially supporting our H2. We also observe the loss of multiple functional groups as species vulnerable to habitat loss become extinct, supporting our H3.
These results support the hypothesis that species vulnerable to habitat loss are also important in maintaining unique functions within ecosystem processes. Functional groups associated with endophytic oviposition and thermal conformer thermoregulation were the most likely to be lost, possibly due to their strong association with environments of higher ecological integrity.
Thus, if species vulnerable to habitat loss maintain unique functions in ecosystems and they are extirpated from a landscape, this will lead to the disappearance of entire functional groups and potentially ecosystem services (if they are not performed by other species).
{"title":"Extinctions Associated With Sensitivity to Habitat Loss Promote Functional Homogenisation and Body Size Increase of Odonata in Amazonian Streams","authors":"Lucas Pereira-Moura, Carolina Gomes Viana, Lucas Ferreira Colares, Karina Dias da Silva, Everton Cruz da Silva, Myckey Kenzy Silva Gonçalves, Lenize Batista Calvão, José Max Barbosa Oliveira-Junior, Leandro Juen, Sheyla Regina Marques Couceiro","doi":"10.1111/fwb.70119","DOIUrl":"https://doi.org/10.1111/fwb.70119","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Extinction processes driven by habitat loss at multiple scales can lead to changes in the taxonomic and functional rarity of biological communities. However, evidence on the direction of these changes remains limited, making more accurate extrapolations about ecosystem functioning difficult. Therefore, our objective was to assess how rarity, functional groups, and species traits of adult Odonata communities change across extinction scenarios at local and regional scales. We tested the following hypotheses: (i) Functional rarity will decrease as species vulnerable to habitat loss go extinct at local and regional scales; (ii) the average body size of adult Odonata will increase as vulnerable species are lost at local and regional scales; and (iii) the loss of functional groups will occur earlier if the species more vulnerable to habitat loss go extinct, because these species are expected to perform unique ecological roles that may vanish with their disappearance.</li>\u0000 \u0000 \u0000 <li>We sampled a total of 128 streams in the Eastern Amazon, recording 4031 individuals representing 42 genera and 141 species. After determining the extinction risk and functional rarity of the community, we simulated three extinction scenarios at both local and regional scales (1—extinction of species more vulnerable to habitat loss, 2—extinction of species more tolerant to habitat loss, and 3—random extinction), calculated our response variables, and tested the observed differences using a nonparametric Friedman test.</li>\u0000 \u0000 \u0000 <li>Our results indicated that communities at local and regional scales tend to lose functional rarity as species vulnerable to habitat loss become extinct, supporting H1. At the local scale, average body size decreased as species more vulnerable to habitat loss became extinct, and at the regional scale, the opposite occurred; that is, there was an increase in average body size as they became extinct, partially supporting our H2. We also observe the loss of multiple functional groups as species vulnerable to habitat loss become extinct, supporting our H3.</li>\u0000 \u0000 \u0000 <li>These results support the hypothesis that species vulnerable to habitat loss are also important in maintaining unique functions within ecosystem processes. Functional groups associated with endophytic oviposition and thermal conformer thermoregulation were the most likely to be lost, possibly due to their strong association with environments of higher ecological integrity.</li>\u0000 \u0000 \u0000 <li>Thus, if species vulnerable to habitat loss maintain unique functions in ecosystems and they are extirpated from a landscape, this will lead to the disappearance of entire functional groups and potentially ecosystem services (if they are not performed by other species).</li>\u0000 ","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145385011","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}
Terrestrial invertebrates are important food resources for fish in forested streams, and understanding their origins as fish prey—whether from air-canopy or ground surface-soil environments within the forest—is essential for the management of headwater catchments. However, the contribution of ground-dwelling invertebrates to fish food resources remains unclear because few studies have quantified their inputs to streams. Here, we investigated the input pathways and composition of terrestrial invertebrates supplied to a channel and preyed upon by fish in a small forested stream in a cool-temperature area of western Japan and evaluated the importance of ground-dwelling invertebrates as a food resource for stream fish.
We used pan-traps placed in the central part of the channel (instream traps) and along the channel margins (bankside traps) to clarify the input pathways of terrestrial invertebrates (vertical pathway via air and canopy; lateral pathway via ground surface and soil). Additionally, terrestrial invertebrates were identified at the class, order, and family levels to determine their typical habitat and compare mass-based composition in terrestrial inputs and fish stomach contents.
The mass of terrestrial invertebrates captured by traps at the channel margin was equivalent to approximately 10 times that in the central part of the channel, mainly due to ground-dwelling invertebrates common in bankside traps but rare in instream traps.
Based on an assessment at the reach scale, the proportion of ground-dwelling invertebrates to total terrestrial inputs (58%) was comparable to their proportion in fish stomach contents (58%). These findings indicate that bankside traps effectively address the methodological limitations of relying solely on instream traps and highlight ground-dwelling invertebrates as an essential component of potential fish prey. However, the correlation between the inputs and stomach contents was notably weaker for ground-dwelling invertebrates (r = 0.47) than for air- and canopy-dwelling invertebrates (r = 0.78). This weak correlation might stem from the complex prey–fish processes, such as the spatial heterogeneity of ground-dwelling invertebrate inputs, their underwater behaviours, and/or fish prey selections.
Our results emphasise the need for quantitative analysis of the lateral movement of ground-dwelling invertebrates to better understand forest–stream ecological linkages through terrestrial invertebrate inputs. Therefore, we conclude that conserving the forest floor and soil environment in riparian areas, as well as vegetation, is crucial for maintaining stream ecosystems.
{"title":"Lateral Movement of Ground-Dwelling Invertebrates Resolves Discrepancies Between Fish Diet and Terrestrial Input Data","authors":"Takehiro Kubo, Hirokazu Haga","doi":"10.1111/fwb.70110","DOIUrl":"https://doi.org/10.1111/fwb.70110","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Terrestrial invertebrates are important food resources for fish in forested streams, and understanding their origins as fish prey—whether from air-canopy or ground surface-soil environments within the forest—is essential for the management of headwater catchments. However, the contribution of ground-dwelling invertebrates to fish food resources remains unclear because few studies have quantified their inputs to streams. Here, we investigated the input pathways and composition of terrestrial invertebrates supplied to a channel and preyed upon by fish in a small forested stream in a cool-temperature area of western Japan and evaluated the importance of ground-dwelling invertebrates as a food resource for stream fish.</li>\u0000 \u0000 \u0000 <li>We used pan-traps placed in the central part of the channel (instream traps) and along the channel margins (bankside traps) to clarify the input pathways of terrestrial invertebrates (vertical pathway via air and canopy; lateral pathway via ground surface and soil). Additionally, terrestrial invertebrates were identified at the class, order, and family levels to determine their typical habitat and compare mass-based composition in terrestrial inputs and fish stomach contents.</li>\u0000 \u0000 \u0000 <li>The mass of terrestrial invertebrates captured by traps at the channel margin was equivalent to approximately 10 times that in the central part of the channel, mainly due to ground-dwelling invertebrates common in bankside traps but rare in instream traps.</li>\u0000 \u0000 \u0000 <li>Based on an assessment at the reach scale, the proportion of ground-dwelling invertebrates to total terrestrial inputs (58%) was comparable to their proportion in fish stomach contents (58%). These findings indicate that bankside traps effectively address the methodological limitations of relying solely on instream traps and highlight ground-dwelling invertebrates as an essential component of potential fish prey. However, the correlation between the inputs and stomach contents was notably weaker for ground-dwelling invertebrates (<i>r</i> = 0.47) than for air- and canopy-dwelling invertebrates (<i>r</i> = 0.78). This weak correlation might stem from the complex prey–fish processes, such as the spatial heterogeneity of ground-dwelling invertebrate inputs, their underwater behaviours, and/or fish prey selections.</li>\u0000 \u0000 \u0000 <li>Our results emphasise the need for quantitative analysis of the lateral movement of ground-dwelling invertebrates to better understand forest–stream ecological linkages through terrestrial invertebrate inputs. Therefore, we conclude that conserving the forest floor and soil environment in riparian areas, as well as vegetation, is crucial for maintaining stream ecosystems.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 10","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145406705","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}
The coexistence of submerged macrophytes is crucial for maintaining ecosystem health and biodiversity in shallow lake ecosystems. The modern coexistence theory (MCT) has been extensively used to explain species coexistence in grasslands and microbial communities by considering average fitness differences and niche differences at local scales. However, this theory has not yet been applied to investigate the coexistence of submerged macrophytes. In freshwater ecosystems, fish play a vital role in regulating the structure of the submerged macrophytes community. Fish could affect inter/intra specific competition of submerged macrophytes by indirectly changing the water environment or directly acting as herbivores, which might be described as apparent competition.
Here, we employed a short-term mesocosm experiment to explore how omnivorous fish (Rhodeus ocellatus) and herbivorous fish (Megalobrama amblycephala) affect the co-existence of rosette-forming macrophytes (Vallisneria denseserrulata) and canopy-forming macrophytes (Myriophyllum spicatum), based on the MCT. We hypothesised that both herbivorous fish and omnivorous fish could influence the co-existence dynamics of these macrophytes through apparent competition, that is two macrophytes interact indirectly through their shared grazer.
In the absence of fish or with only omnivorous fish present, V. denseserrulata and M. spicatum couldn't stably coexist, with V. denseserrulata exhibiting stronger growth and clonal reproductive with more ramets, winning the interspecific competition according to the prediction of MCT. However, the herbivorous fish, with preferential grazing, altered their fitness and niche differences between the macrophytes, promoting their coexistence.
Our results reveal a case study of apparent competition between submerged macrophytes via fish presence, which provides insightful solutions for maintaining high species diversity of submerged macrophytes in restored shallow lakes.
{"title":"Apparent Competition Between Two Submerged Macrophytes via Fish: Evidence From a Mesocosm Study","authors":"Manli Xia, Wei Liu, Chaoyu Tian, Cheng Daomin, Wei Li, Yu Cao","doi":"10.1111/fwb.70116","DOIUrl":"https://doi.org/10.1111/fwb.70116","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>The coexistence of submerged macrophytes is crucial for maintaining ecosystem health and biodiversity in shallow lake ecosystems. The modern coexistence theory (MCT) has been extensively used to explain species coexistence in grasslands and microbial communities by considering average fitness differences and niche differences at local scales. However, this theory has not yet been applied to investigate the coexistence of submerged macrophytes. In freshwater ecosystems, fish play a vital role in regulating the structure of the submerged macrophytes community. Fish could affect inter/intra specific competition of submerged macrophytes by indirectly changing the water environment or directly acting as herbivores, which might be described as apparent competition.</li>\u0000 \u0000 \u0000 <li>Here, we employed a short-term mesocosm experiment to explore how omnivorous fish (<i>Rhodeus ocellatus</i>) and herbivorous fish (<i>Megalobrama amblycephala</i>) affect the co-existence of rosette-forming macrophytes (<i>Vallisneria denseserrulata</i>) and canopy-forming macrophytes (<i>Myriophyllum spicatum</i>), based on the MCT. We hypothesised that both herbivorous fish and omnivorous fish could influence the co-existence dynamics of these macrophytes through apparent competition, that is two macrophytes interact indirectly through their shared grazer.</li>\u0000 \u0000 \u0000 <li>In the absence of fish or with only omnivorous fish present, <i>V</i>. <i>denseserrulata</i> and <i>M. spicatum</i> couldn't stably coexist, with <i>V</i>. <i>denseserrulata</i> exhibiting stronger growth and clonal reproductive with more ramets, winning the interspecific competition according to the prediction of MCT. However, the herbivorous fish, with preferential grazing, altered their fitness and niche differences between the macrophytes, promoting their coexistence.</li>\u0000 \u0000 \u0000 <li>Our results reveal a case study of apparent competition between submerged macrophytes via fish presence, which provides insightful solutions for maintaining high species diversity of submerged macrophytes in restored shallow lakes.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 10","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145367080","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 Peso, Luc De Meester, Tom De Bie, Bram Vanschoenwinkel, Gerald Louette, Luc Brendonck, Koen Martens, Steven A. J. Declerck, Pieter Lemmens
A substantial body of research has assessed the relative importance of local and regional factors shaping ecological communities, often using lakes and ponds as model systems. However, little is known about how habitat age can help to explain current community structure. The present study investigates the effect of pond age on zooplankton community composition and diversity in farmland ponds.
We used a dataset of > 100 morphologically similar farmland ponds of different ages (recent: 3 years; older: 4–15 years, and old: > 15 years) to analyse the extent to which the diversity and composition of current water flea assemblages (Crustacea; Anomopoda) reflect variation in pond age.
Young ponds had lower local species richness than old ponds and their communities were nested within those in ecologically similar old ponds. The presence of macrophytes enhanced local richness by promoting the establishment of additional species, while the presence of fish resulted in community turnover and lower local species richness compared to old ponds without fish.
Our results demonstrate that pond age is an important factor determining cladoceran species richness and community composition. Newly created ponds are rapidly colonised by regionally common species, while the colonisation by regionally rare species was more restricted. In older ponds, effective species sorting occurred in response to changes in local environmental conditions associated with the establishment of macrophytes and fish.
These findings highlight the need for longer time perspectives in colonisation studies to understand patterns of community succession in newly created habitats.
{"title":"Community Assembly of Cladoceran Zooplankton in Relation to Pond Age and the Establishment of Macrophytes and Fish","authors":"Maria Peso, Luc De Meester, Tom De Bie, Bram Vanschoenwinkel, Gerald Louette, Luc Brendonck, Koen Martens, Steven A. J. Declerck, Pieter Lemmens","doi":"10.1111/fwb.70118","DOIUrl":"https://doi.org/10.1111/fwb.70118","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>A substantial body of research has assessed the relative importance of local and regional factors shaping ecological communities, often using lakes and ponds as model systems. However, little is known about how habitat age can help to explain current community structure. The present study investigates the effect of pond age on zooplankton community composition and diversity in farmland ponds.</li>\u0000 \u0000 \u0000 <li>We used a dataset of > 100 morphologically similar farmland ponds of different ages (recent: 3 years; older: 4–15 years, and old: > 15 years) to analyse the extent to which the diversity and composition of current water flea assemblages (Crustacea; Anomopoda) reflect variation in pond age.</li>\u0000 \u0000 \u0000 <li>Young ponds had lower local species richness than old ponds and their communities were nested within those in ecologically similar old ponds. The presence of macrophytes enhanced local richness by promoting the establishment of additional species, while the presence of fish resulted in community turnover and lower local species richness compared to old ponds without fish.</li>\u0000 \u0000 \u0000 <li>Our results demonstrate that pond age is an important factor determining cladoceran species richness and community composition. Newly created ponds are rapidly colonised by regionally common species, while the colonisation by regionally rare species was more restricted. In older ponds, effective species sorting occurred in response to changes in local environmental conditions associated with the establishment of macrophytes and fish.</li>\u0000 \u0000 \u0000 <li>These findings highlight the need for longer time perspectives in colonisation studies to understand patterns of community succession in newly created habitats.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 10","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145366610","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}
{"title":"Novel Methods in Cladoceran Size Structure Analysis Reveal ~60 Years of Trophic Change in a Sediment Core From a Great Lakes Area of Concern (Bay of Quinte, Lake Ontario)","authors":"Isaac Armstrong, Brian F. Cumming","doi":"10.1111/fwb.70105","DOIUrl":"https://doi.org/10.1111/fwb.70105","url":null,"abstract":"<p>\u0000 \u0000 </p>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 10","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/fwb.70105","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145366386","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}
1. Environmental conditions undergo considerable variation with increasing elevation, where high elevations can detrimentally affect plant growth and distribution. Ranunculus bungei, a widespread aquatic plant in the Tibetan Plateau, successfully thrives across a wide range of elevations. This study aims to clarify the photosynthetic and structural adaptability of R. bungei to varying elevations.
2. The study conducted in situ experiments with R. bungei across 18 elevation gradients (2923 m–4906 m) to analyse pigment content, HCO3− utilisation, CAM metabolism and leaf structure. It also examined environmental factors to investigate how the CO2 concentrating mechanisms (CCMs) and leaf structure of R. bungei respond to elevation-driven varying environment.
3. A significant decline in Chlorophyll a, Chlorophyll a/b, and carotenoid content occurs with increasing elevation, indicating an adaptive response to mitigate potential oxidative stress associated with harsh conditions at higher elevations. Ranunculus bungei exhibits CAM metabolism at elevations below 3010 m; however, both CAM activity and HCO3− utilisation decrease with rising elevation. Key environmental factors influencing CAM activity include elevation, water temperature and CO2 concentration. R. bungei leaf thickness responded nonlinearly to elevation, showing initial decreases followed by increases past the inflection elevation. A significant positive correlation exists between the ratio of air space area to leaf lobe area and the proportion of total inorganic carbon to alkalinity (CT/Alk) in pH-drift experiments, indicating that R. bungei can adjust its air space according to the availability of inorganic carbon sources.
4. Elevation variations significantly affect the CCMs and anatomy of R. bungei on the Tibetan Plateau. These findings enhance our understanding of the plasticity of CCMs and the ecological adaptability of R. bungei, allowing for predictions about the species' responses to future climate scenarios.
{"title":"Elevational Influences on CO2 Concentrating Mechanisms and Anatomy in Ranunculus bungei on the Tibetan Plateau","authors":"Jiajia Jia, Hongsheng Jiang, Liyuan Wang, Huan Xu, Wei Li, Wenmin Huang","doi":"10.1111/fwb.70117","DOIUrl":"https://doi.org/10.1111/fwb.70117","url":null,"abstract":"<div>\u0000 \u0000 <p>1. Environmental conditions undergo considerable variation with increasing elevation, where high elevations can detrimentally affect plant growth and distribution. <i>Ranunculus bungei</i>, a widespread aquatic plant in the Tibetan Plateau, successfully thrives across a wide range of elevations. This study aims to clarify the photosynthetic and structural adaptability of <i>R. bungei</i> to varying elevations.</p>\u0000 <p>2. The study conducted in situ experiments with <i>R. bungei</i> across 18 elevation gradients (2923 m–4906 m) to analyse pigment content, HCO<sub>3</sub><sup>−</sup> utilisation, CAM metabolism and leaf structure. It also examined environmental factors to investigate how the CO<sub>2</sub> concentrating mechanisms (CCMs) and leaf structure of <i>R. bungei</i> respond to elevation-driven varying environment.</p>\u0000 <p>3. A significant decline in Chlorophyll <i>a</i>, Chlorophyll <i>a</i>/<i>b</i>, and carotenoid content occurs with increasing elevation, indicating an adaptive response to mitigate potential oxidative stress associated with harsh conditions at higher elevations. <i>Ranunculus bungei</i> exhibits CAM metabolism at elevations below 3010 m; however, both CAM activity and HCO<sub>3</sub><sup>−</sup> utilisation decrease with rising elevation. Key environmental factors influencing CAM activity include elevation, water temperature and CO<sub>2</sub> concentration. <i>R. bungei</i> leaf thickness responded nonlinearly to elevation, showing initial decreases followed by increases past the inflection elevation. A significant positive correlation exists between the ratio of air space area to leaf lobe area and the proportion of total inorganic carbon to alkalinity (C<sub>T</sub>/Alk) in pH-drift experiments, indicating that <i>R. bungei</i> can adjust its air space according to the availability of inorganic carbon sources.</p>\u0000 <p>4. Elevation variations significantly affect the CCMs and anatomy of <i>R. bungei</i> on the Tibetan Plateau. These findings enhance our understanding of the plasticity of CCMs and the ecological adaptability of <i>R. bungei</i>, allowing for predictions about the species' responses to future climate scenarios.</p>\u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 10","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145366317","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}
1. Understanding how adaptation to fluctuating resource availability drives life-history trade-offs, and in turn promotes niche differentiation among species, is central to ecology. The gleaner–opportunist framework, in which gleaners are better adapted to low resource levels and opportunists to high levels, represents one way in which divergent resource-use strategies can partition ecological niches across taxa. However, whether such strategies exist within species remains unclear. Here, I tested for intraspecific variation in resource-use strategies in a clonal rotifer grazer.
2. Using an image-based high-throughput phenotyping system, I analyzed population growth rates of 98 genotypes across a resource gradient.
3. I showed that clones exhibited a gleaner-opportunist trade-off, as demonstrated by a positive correlation between maximum growth rate (μmax) and resource threshold parameters (k and R*), coupled with divergent fitness optima at low versus high resource levels. Specifically, clones that excelled under low-resource conditions (gleaners) exhibited lower k and R* values, whereas those performing better at high-resource levels (opportunists) showed higher μmax.
4. I also identified a few “superclones,” which had superior performance across all environments, challenging the notion of a singular adaptive axis and suggesting that additional ecological and evolutionary mechanisms maintain phenotypic diversity.
5. These results demonstrate that intraspecific variation in resource use strategies mirrors patterns previously observed between species, yet the coexistence of superclones highlights additional complexity in adaptive landscapes. These findings underscore the importance of genetic diversity in buffering populations against environmental variability and provide a framework for linking individual-level traits to broader eco-evolutionary dynamics.
{"title":"Characterising Intraspecific Resource Use in a Rotifer Grazer Using High-Throughput Phenotyping","authors":"Claus-Peter Stelzer","doi":"10.1111/fwb.70115","DOIUrl":"https://doi.org/10.1111/fwb.70115","url":null,"abstract":"<p>1. Understanding how adaptation to fluctuating resource availability drives life-history trade-offs, and in turn promotes niche differentiation among species, is central to ecology. The gleaner–opportunist framework, in which gleaners are better adapted to low resource levels and opportunists to high levels, represents one way in which divergent resource-use strategies can partition ecological niches across taxa. However, whether such strategies exist within species remains unclear. Here, I tested for intraspecific variation in resource-use strategies in a clonal rotifer grazer.</p><p>2. Using an image-based high-throughput phenotyping system, I analyzed population growth rates of 98 genotypes across a resource gradient.</p><p>3. I showed that clones exhibited a gleaner-opportunist trade-off, as demonstrated by a positive correlation between maximum growth rate (<i>μ</i><sub>max</sub>) and resource threshold parameters (<i>k</i> and <i>R</i>*), coupled with divergent fitness optima at low versus high resource levels. Specifically, clones that excelled under low-resource conditions (gleaners) exhibited lower <i>k</i> and <i>R</i>* values, whereas those performing better at high-resource levels (opportunists) showed higher <i>μ</i><sub>max</sub>.</p><p>4. I also identified a few “superclones,” which had superior performance across all environments, challenging the notion of a singular adaptive axis and suggesting that additional ecological and evolutionary mechanisms maintain phenotypic diversity.</p><p>5. These results demonstrate that intraspecific variation in resource use strategies mirrors patterns previously observed between species, yet the coexistence of superclones highlights additional complexity in adaptive landscapes. These findings underscore the importance of genetic diversity in buffering populations against environmental variability and provide a framework for linking individual-level traits to broader eco-evolutionary dynamics.</p>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 10","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/fwb.70115","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145317160","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}
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