Natalia S. Alves, Daiane E. Cavallari, Welber S. Smith
{"title":"Fish Assemblages in an Urbanized Neotropical Basin: Influence of Environmental Factors Across Dry and Rainy Periods","authors":"Natalia S. Alves, Daiane E. Cavallari, Welber S. Smith","doi":"10.1002/iroh.70044","DOIUrl":"https://doi.org/10.1002/iroh.70044","url":null,"abstract":"<p>This study investigated the effects of season and environmental disturbances on fish communities in neotropical rivers of the Sorocaba basin, a Sub-Basin of the Paraná River in Southeast Brazil, based on sampling 1196 individuals from 49 species, including two non-native and one threatened with extinction. Greater richness and abundance were recorded in the rainy season, but the community structure remained stable between periods, indicating resilience to climatic variations. The rivers showed marked differences: the Sorocaba River stood out for its high diversity and low dominance, while the Una River exhibited the lowest richness and highest dominance, reflecting a gradient of anthropogenic impact. Variables such as riparian vegetation, fast flow, and substrates exerted a greater influence on species distribution than seasonality. Larger rivers supported greater abundance, but habitat degradation, especially the loss of riparian vegetation, threatens local biodiversity. Despite advances in sanitation, problems such as pollution and the presence of invasive species persist. Conservation should prioritize protecting riparian vegetation, maintaining habitats with fast flow and diverse substrates, and managing non-native species. The observed stability is maintained by generalist species and preserved riparian forest stretches, yet anthropogenic pressure remains the main risk to the fish fauna. Integrated management measures are urgently needed to reconcile anthropogenic use of water resources and the preservation of these neotropical rivers.</p>","PeriodicalId":54928,"journal":{"name":"International Review of Hydrobiology","volume":"111 2","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/iroh.70044","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148753169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mateus M. Pires, Lenize B. Calvão, Eduardo Périco, Leandro Juen
{"title":"Spatiotemporal Changes in Odonata Assemblages in Freshwater and Coastal Habitats Associated With the Onset of the Operation of an Industrial-Mining Complex in the Eastern Amazon","authors":"Mateus M. Pires, Lenize B. Calvão, Eduardo Périco, Leandro Juen","doi":"10.1002/iroh.70042","DOIUrl":"https://doi.org/10.1002/iroh.70042","url":null,"abstract":"<div>\u0000 \u0000 <p>Industrial-mining expansion is reshaping ecological processes across tropical landscapes at an unprecedented rate, yet its consequences to aquatic biodiversity remain insufficiently quantified. We used a before-after repeated-measures design to assess temporal changes in Odonata assemblages following the onset of operations at an industrial-mining complex in streams and mangroves along a gradient of potential spatial exposure in the eastern Amazon (State of Pará, northern Brazil). Adult Odonata were collected at three sites from each habitat type (located at increasing distances from the industrial-mining complex) across multiple quarters of the regional dry season, both in the year preceding and in the first year of the operation of the industrial-mining complex. In streams, Odonata alpha diversity (richness and Shannon diversity) consistently decreased after the onset of the operation and was accompanied by marked and variable shifts in composition. Particularly, the abundance of disturbance-tolerant Anisoptera taxa decreased near the complex, while the abundance of specialist Zygoptera taxa decreased in all streams after the onset of operation. Across mangroves, Odonata assemblages varied primarily with spatial distance from the complex and showed weaker temporal changes in composition between operational phases. In particular, Odonata assemblages in the mangroves near the industrial-mining complex exhibited greater compositional variation than in mangroves farther away. Such responses highlight the habitat-specific sensitivity of Odonata to land-use changes, with stream assemblages appearing more vulnerable to industrial-mining impacts than mangroves. Our findings underscore the importance of incorporating multiple habitat types and explicit spatial gradients into environmental impact assessments and reinforce the value of Odonata as bioindicators of aquatic ecosystem health in tropical forest landscapes in the Global South.</p></div>","PeriodicalId":54928,"journal":{"name":"International Review of Hydrobiology","volume":"111 2","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148616037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Density-Dependent Suppression of Invasive Hydrilla verticillata by Two Native Submerged Macrophytes Under Greenhouse Conditions","authors":"Angela Maroti Diaz de Leon, Jeffrey T. Hutchinson","doi":"10.1002/iroh.70043","DOIUrl":"https://doi.org/10.1002/iroh.70043","url":null,"abstract":"<div>\u0000 \u0000 <p>Hydrilla (<i>Hydrilla verticillata</i>) is an invasive submerged macrophyte that can dominate freshwater plant communities and complicate restoration efforts. Management options may be limited in systems containing sensitive native species, making competitive suppression by native macrophytes a potentially useful complementary strategy. We evaluated interactions between <i>H. verticillata</i> and two widespread native species, <i>Heteranthera dubia</i> and <i>Potamogeton illinoensis</i>, in greenhouse mesocosms using additive-density and equal-ratio experiments. Apical tips of the three species were planted into sediment-filled 19 L mesocosms and grown under winter, summer, or spring greenhouse conditions. In additive-density experiments, hydrilla root and shoot biomass and relative growth rate generally declined as the initial density of hydrilla decreased relative to the native species. Suppression of hydrilla growth was more evident in the winter experiment, although hydrilla tuber production was also greater during winter. In equal-ratio experiments, <i>H</i>. <i>dubia</i> showed growth rates comparable to hydrilla, whereas <i>P</i>. <i>illinoensis</i> allocated proportionally more biomass to roots and had lower relative growth rates. Overall, the results suggest that dense plantings of native submerged macrophytes may reduce hydrilla growth under controlled conditions, particularly when combined with prior hydrilla removal. Field studies are needed to determine whether winter restoration plantings can suppress hydrilla regrowth from established tuber banks.</p>\u0000 </div>","PeriodicalId":54928,"journal":{"name":"International Review of Hydrobiology","volume":"111 2","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148616030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Paula Caroline dos Reis Oliveira, Betina Kozlowsky-Suzuki, Cleber Cunha Figueredo, Adriana Oliveira Medeiros, Doriedson Ferreira Gomes, Christina W. Castelo Branco, Priscilla Carvalho, Renan de Souza Rezende, Tássia Malacarne, Vivian de Mello de Cionek, Iola Gonçalves Boëchat, Paulo Henrique Costa Corgosinho, Fabrício Barreto Teresa, Rodrigo Assis de Carvalho, Larissa Corteletti da Costa, Lucia Ribeiro Rodrigues, Gustavo Stolzenberg Colares, Louise Cristina Gomes, Fabiana Schneck, Renato Tavares Martins, Thaisa Sala Michelan, Matheus Maximilian Ratz Scoarize, Rosilene Luciana Delariva, Evanilde Benedito, Björn Gücker
{"title":"Freshwater Biodiversity Research in Brazil: Trends from a Systematic Review and Topic Modeling","authors":"Paula Caroline dos Reis Oliveira, Betina Kozlowsky-Suzuki, Cleber Cunha Figueredo, Adriana Oliveira Medeiros, Doriedson Ferreira Gomes, Christina W. Castelo Branco, Priscilla Carvalho, Renan de Souza Rezende, Tássia Malacarne, Vivian de Mello de Cionek, Iola Gonçalves Boëchat, Paulo Henrique Costa Corgosinho, Fabrício Barreto Teresa, Rodrigo Assis de Carvalho, Larissa Corteletti da Costa, Lucia Ribeiro Rodrigues, Gustavo Stolzenberg Colares, Louise Cristina Gomes, Fabiana Schneck, Renato Tavares Martins, Thaisa Sala Michelan, Matheus Maximilian Ratz Scoarize, Rosilene Luciana Delariva, Evanilde Benedito, Björn Gücker","doi":"10.1002/iroh.70039","DOIUrl":"https://doi.org/10.1002/iroh.70039","url":null,"abstract":"<p>Brazil is a megadiverse country that hosts six major biomes and a vast freshwater network. Despite this richness, research on freshwater biodiversity has been heterogeneous across regions, communities, and time, leaving significant knowledge gaps. Previous syntheses have typically focused on individual taxa or specific biomes, providing important but fragmented perspectives that limit cross-community comparisons. To assess these limitations, we reviewed literature on fungi, phytoplankton, macrophytes, zooplankton, macroinvertebrate, meiofauna, and fish, applying text mining and topic modeling. The earliest studies, dating back to the 1970s, focused on zooplankton. From 2005 onward, research expanded rapidly, with fish and macroinvertebrate emerging as the most studied groups, while fungi remained the least investigated. Topic mapping revealed community-specific emphases. Fish research often addressed dam impacts; macroinvertebrate research focused on Ephemeroptera, Plecoptera, and Trichoptera (EPT) biotic indices in lotic ecosystems; zooplankton studies highlighted trophic ecology in reservoirs; phytoplankton research emphasized floodplains, cyanobacteria blooms, and abiotic variation; aquatic macrophyte studies explored metacommunities and shallow lakes; meiofauna research centered on Oligochaeta biodiversity; and studies on fungi addressed interactions with macroinvertebrate. The only cross-community topic was plant-associated dynamics. We found more rising (“hot”) than declining (“cold”) topics. Hot topics appeared in all groups except phytoplankton and zooplankton. Cold topics included the EPT index (macroinvertebrate) and spatial variation in reservoirs (zooplankton). While most studies addressed fundamental ecology, applied themes such as bioassessment, fisheries, and land-use change were less common. Experimental approaches were rare. Overall, Brazilian freshwater research has advanced in scope but remains unbalanced. Future efforts should strengthen applied and experimental ecological studies (e.g., through long-term and large-scale field experiments and mesocosms), expand knowledge of fungi and meiofauna, and improve taxonomy and functional trait data across freshwater communities, especially in tropical regions.</p>","PeriodicalId":54928,"journal":{"name":"International Review of Hydrobiology","volume":"111 2","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/iroh.70039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148466712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Observations on the Burrow Structures and Larval Behavior of Ephoron shigae (Takahashi, 1924) (Ephemeroptera: Polymitarcyidae) in River Sediments","authors":"Yuichi Hasuda, Hitoshi Sugiyama","doi":"10.1002/iroh.70040","DOIUrl":"https://doi.org/10.1002/iroh.70040","url":null,"abstract":"<p>The larvae of the mayfly <i>Ephoron shigae</i> (Takahashi, 1924) (Ephemeroptera: Polymitarcyidae) inhabit distinctive U-shaped burrows in river and lake sediments, yet their ecology remains poorly documented. Using newly developed mechatronic technology, we obtained continuous observations that revealed new aspects of larval behavior. The larvae first construct a U-shaped burrow and then extend it by adding an additional channel without leaving the original structure. This channel branches from the deepest point of the burrow and faces upstream, opposite the river current. Our fluid-engineering analysis indicates that constructing this branch at an acute angle enhances the inflow of detritus and oxygen, the larvae's primary resources. As bioirrigators, <i>E. shigae</i> larvae may use this upstream-facing channel to enhance oxygen supply within the burrow, particularly when oxygen levels decline due to the respiration of larvae and microorganisms. Robotic and artificial water-channel systems now enable automated observation of burrowing mayflies like <i>E. shigae</i> in bottom sediments.</p>","PeriodicalId":54928,"journal":{"name":"International Review of Hydrobiology","volume":"111 2","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/iroh.70040","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148389213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
João Miguel Merces Bega, Murilo de Souza Ferreira, Nícolas Reinaldo Finkler, Carlos Eduardo de Campos Jordão, Davi Gasparini Fernandes Cunha
{"title":"Drivers of Greenhouse Gas Emissions in Tropical Riverine Systems Across a Gradient of Human Impact","authors":"João Miguel Merces Bega, Murilo de Souza Ferreira, Nícolas Reinaldo Finkler, Carlos Eduardo de Campos Jordão, Davi Gasparini Fernandes Cunha","doi":"10.1002/iroh.70038","DOIUrl":"https://doi.org/10.1002/iroh.70038","url":null,"abstract":"<p>Tropical lotic ecosystems are important sources of greenhouse gas emissions, yet the magnitude and variability of such emissions remain poorly constrained. Here, we quantified spatial and short-term temporal variability of carbon dioxide (CO<sub>2</sub>) and methane (CH<sub>4</sub>) fluxes across tropical riverine systems spanning a gradient of human impact, while identifying potential biogeochemical and physical drivers of these fluxes. All systems acted as net sources of both gases. Fluxes varied widely among sites [49–1,701 (CO<sub>2</sub>) and 0.6–85.9 mmol m<sup>−2</sup> d<sup>−1</sup> (CH<sub>4</sub>)], while short-term temporal variability was limited, likely due to relatively uniform climatic conditions during the study period. In particular, treated wastewater inputs, not properly captured by conventional land use metrics, contributed to elevated emissions. CO<sub>2</sub> emissions were driven by ecosystem respiration, highlighting the role of net heterotrophy, with additional contributions from sediment inorganic carbon and methane fluxes. By contrast, CH<sub>4</sub> emissions were more closely linked to pH and gas exchange velocity, reflecting the combined influence of sediment production and physical transport processes. These findings advance understanding of the controls on carbon emissions in tropical riverine systems, emphasizing the role of wastewater inputs and metabolic processes in shaping and scaling emissions. They also provide a framework for improving the representation of tropical river networks in regional and global budgets and for guiding strategies to mitigate emissions in impacted freshwater systems.</p>","PeriodicalId":54928,"journal":{"name":"International Review of Hydrobiology","volume":"111 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/iroh.70038","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148324320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
João Miguel Merces Bega, Murilo de Souza Ferreira, Nícolas Reinaldo Finkler, Carlos Eduardo de Campos Jordão, Davi Gasparini Fernandes Cunha
{"title":"Drivers of Greenhouse Gas Emissions in Tropical Riverine Systems Across a Gradient of Human Impact","authors":"João Miguel Merces Bega, Murilo de Souza Ferreira, Nícolas Reinaldo Finkler, Carlos Eduardo de Campos Jordão, Davi Gasparini Fernandes Cunha","doi":"10.1002/iroh.70038","DOIUrl":"https://doi.org/10.1002/iroh.70038","url":null,"abstract":"<p>Tropical lotic ecosystems are important sources of greenhouse gas emissions, yet the magnitude and variability of such emissions remain poorly constrained. Here, we quantified spatial and short-term temporal variability of carbon dioxide (CO<sub>2</sub>) and methane (CH<sub>4</sub>) fluxes across tropical riverine systems spanning a gradient of human impact, while identifying potential biogeochemical and physical drivers of these fluxes. All systems acted as net sources of both gases. Fluxes varied widely among sites [49–1,701 (CO<sub>2</sub>) and 0.6–85.9 mmol m<sup>−2</sup> d<sup>−1</sup> (CH<sub>4</sub>)], while short-term temporal variability was limited, likely due to relatively uniform climatic conditions during the study period. In particular, treated wastewater inputs, not properly captured by conventional land use metrics, contributed to elevated emissions. CO<sub>2</sub> emissions were driven by ecosystem respiration, highlighting the role of net heterotrophy, with additional contributions from sediment inorganic carbon and methane fluxes. By contrast, CH<sub>4</sub> emissions were more closely linked to pH and gas exchange velocity, reflecting the combined influence of sediment production and physical transport processes. These findings advance understanding of the controls on carbon emissions in tropical riverine systems, emphasizing the role of wastewater inputs and metabolic processes in shaping and scaling emissions. They also provide a framework for improving the representation of tropical river networks in regional and global budgets and for guiding strategies to mitigate emissions in impacted freshwater systems.</p>","PeriodicalId":54928,"journal":{"name":"International Review of Hydrobiology","volume":"111 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/iroh.70038","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148324054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alena-Maria Maidel, Vanessa Fabienne Bischoff, Hendrik Schubert
{"title":"Acclimation of Charophytes to Spectral Composition of Light at Limiting Irradiances","authors":"Alena-Maria Maidel, Vanessa Fabienne Bischoff, Hendrik Schubert","doi":"10.1002/iroh.70037","DOIUrl":"https://doi.org/10.1002/iroh.70037","url":null,"abstract":"<p>Irradiance is regarded as a key factor determining the maximum colonization depth (<i>Z</i><sub>0</sub>) of submerged macrophytes. However, the relevance of acclimation capabilities to spectral composition under such low-light conditions remains poorly understood. To address this gap, the present study tested whether spectral composition, in addition to light intensity, affects physiological performance in <i>Chara globularis</i> Thuill. and <i>Chara hispida</i> L., two charophyte species differing in depth distribution. Individuals were cultivated for 5 weeks under three low irradiances below the photosynthesis light saturation level (6, 12, and 24 µmol photons m<sup>−2</sup>s<sup>−1</sup>); each irradiance given at four different spectral compositions (full spectrum and blue-, green-, or yellow-wavelength dominated). Daily growth rate, biomass-related parameters, pigment composition (chlorophylls and carotenoids), and photosynthetic light-response parameters were quantified. Across treatments, growth declined with decreasing irradiance in both species, confirming light quantity as the primary constraint, whereas spectral composition had no significant effect on growth or biomass-related parameters. Pigment composition differed consistently between species, with <i>C. globularis</i> exhibiting higher chlorophyll <i>a</i> and carotenoid concentrations across all treatments. Spectral effects on pigment composition were weak, restricted to the highest irradiance, and observed exclusively in <i>C. globularis</i>. Despite these differences, photosynthetic parameters remained largely stable across treatments. The initial slope of the photosynthesis-irradiance curve (α) showed no interspecific differences, while the light saturation point (I<sub><i>k</i></sub>) was consistently higher in <i>C. globularis</i> than in <i>C. hispida</i>. Overall, physiological responses were dominated by light intensity and species identity, while spectral effects were minor and conditional. These findings indicate that charophytes, owing to their comparatively low organizational complexity and maintenance demands, do not appear to gain a functional advantage from strong spectral acclimation under low irradiance. Instead, physiological stability emerges as the prevailing strategy, with the greater plasticity of <i>C. globularis</i> potentially facilitating persistence near the lower macrophyte limit.</p>","PeriodicalId":54928,"journal":{"name":"International Review of Hydrobiology","volume":"111 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/iroh.70037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148324186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alena-Maria Maidel, Vanessa Fabienne Bischoff, Hendrik Schubert
{"title":"Acclimation of Charophytes to Spectral Composition of Light at Limiting Irradiances","authors":"Alena-Maria Maidel, Vanessa Fabienne Bischoff, Hendrik Schubert","doi":"10.1002/iroh.70037","DOIUrl":"https://doi.org/10.1002/iroh.70037","url":null,"abstract":"<p>Irradiance is regarded as a key factor determining the maximum colonization depth (<i>Z</i><sub>0</sub>) of submerged macrophytes. However, the relevance of acclimation capabilities to spectral composition under such low-light conditions remains poorly understood. To address this gap, the present study tested whether spectral composition, in addition to light intensity, affects physiological performance in <i>Chara globularis</i> Thuill. and <i>Chara hispida</i> L., two charophyte species differing in depth distribution. Individuals were cultivated for 5 weeks under three low irradiances below the photosynthesis light saturation level (6, 12, and 24 µmol photons m<sup>−2</sup>s<sup>−1</sup>); each irradiance given at four different spectral compositions (full spectrum and blue-, green-, or yellow-wavelength dominated). Daily growth rate, biomass-related parameters, pigment composition (chlorophylls and carotenoids), and photosynthetic light-response parameters were quantified. Across treatments, growth declined with decreasing irradiance in both species, confirming light quantity as the primary constraint, whereas spectral composition had no significant effect on growth or biomass-related parameters. Pigment composition differed consistently between species, with <i>C. globularis</i> exhibiting higher chlorophyll <i>a</i> and carotenoid concentrations across all treatments. Spectral effects on pigment composition were weak, restricted to the highest irradiance, and observed exclusively in <i>C. globularis</i>. Despite these differences, photosynthetic parameters remained largely stable across treatments. The initial slope of the photosynthesis-irradiance curve (α) showed no interspecific differences, while the light saturation point (I<sub><i>k</i></sub>) was consistently higher in <i>C. globularis</i> than in <i>C. hispida</i>. Overall, physiological responses were dominated by light intensity and species identity, while spectral effects were minor and conditional. These findings indicate that charophytes, owing to their comparatively low organizational complexity and maintenance demands, do not appear to gain a functional advantage from strong spectral acclimation under low irradiance. Instead, physiological stability emerges as the prevailing strategy, with the greater plasticity of <i>C. globularis</i> potentially facilitating persistence near the lower macrophyte limit.</p>","PeriodicalId":54928,"journal":{"name":"International Review of Hydrobiology","volume":"111 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/iroh.70037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148324284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}