Samiris Pereira da Silva, Fernanda Melo Carneiro, João Carlos Nabout
The notion that biodiversity begets greater ecosystem functioning is an enduring paradigm in ecology, supported by a growing body of research demonstrating the significant effects of biodiversity on ecosystem functioning (BEF). These studies use several diversity metrics, which can be estimated through taxonomic, functional and molecular approaches.
Here we aim to investigate the performance of different approaches (taxonomic, functional and molecular), considering the different biodiversity metrics in each approach (e.g., richness, composition, among others). Additionally, we assess the individual response of ecosystem processes (e.g., productivity, decomposition, among others) to biodiversity in each approach. To this end, we perform a review and meta-analysis of studies that assessed BEF relationship in continental aquatic environments, encompassing 94 studies and 322 effect sizes. Our data set includes diverse contexts, with different organisms, environments and ecosystem processes.
We found an overall positive association between biodiversity and the functioning of continental aquatic ecosystems (Effect size = 0.37). We also found differences in the proportions of biodiversity metrics applied in the studies between the different approaches, as well as some geographic bias, with a predominance of studies conducted in the northern hemisphere. Additionally, lakes were the most commonly studied systems, and productivity functions were frequently analysed. We found that the molecular approach, applied exclusively in microbial studies in our dataset, showed better performance in evaluating the BEF relationship.
Despite the strengths of the molecular approach, it is not without limitations. Some challenges such as high costs of sequencing and maintaining database infrastructure, can hinder its application. In light of these limitations, we understand that applying functional approaches, specifically functional richness and functional evenness metrics, in the study of the BEF relationship in continental aquatic ecosystems is promising. This can be an alternative for the continuity and advancement of studies of the BEF relationship in these environments. We also highlighted the need for studies in the southern hemisphere, covering the different freshwater ecosystem and multiple functions.
{"title":"Different Approaches to Measuring Diversity Affect the Strength of the Relationship Between Biodiversity and Ecosystem Function in Freshwater Studies: A Meta-Analysis","authors":"Samiris Pereira da Silva, Fernanda Melo Carneiro, João Carlos Nabout","doi":"10.1111/fwb.70002","DOIUrl":"https://doi.org/10.1111/fwb.70002","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>The notion that biodiversity begets greater ecosystem functioning is an enduring paradigm in ecology, supported by a growing body of research demonstrating the significant effects of biodiversity on ecosystem functioning (BEF). These studies use several diversity metrics, which can be estimated through taxonomic, functional and molecular approaches.</li>\u0000 \u0000 \u0000 <li>Here we aim to investigate the performance of different approaches (taxonomic, functional and molecular), considering the different biodiversity metrics in each approach (e.g., richness, composition, among others). Additionally, we assess the individual response of ecosystem processes (e.g., productivity, decomposition, among others) to biodiversity in each approach. To this end, we perform a review and meta-analysis of studies that assessed BEF relationship in continental aquatic environments, encompassing 94 studies and 322 effect sizes. Our data set includes diverse contexts, with different organisms, environments and ecosystem processes.</li>\u0000 \u0000 \u0000 <li>We found an overall positive association between biodiversity and the functioning of continental aquatic ecosystems (Effect size = 0.37). We also found differences in the proportions of biodiversity metrics applied in the studies between the different approaches, as well as some geographic bias, with a predominance of studies conducted in the northern hemisphere. Additionally, lakes were the most commonly studied systems, and productivity functions were frequently analysed. We found that the molecular approach, applied exclusively in microbial studies in our dataset, showed better performance in evaluating the BEF relationship.</li>\u0000 \u0000 \u0000 <li>Despite the strengths of the molecular approach, it is not without limitations. Some challenges such as high costs of sequencing and maintaining database infrastructure, can hinder its application. In light of these limitations, we understand that applying functional approaches, specifically functional richness and functional evenness metrics, in the study of the BEF relationship in continental aquatic ecosystems is promising. This can be an alternative for the continuity and advancement of studies of the BEF relationship in these environments. We also highlighted the need for studies in the southern hemisphere, covering the different freshwater ecosystem and multiple functions.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143248487","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}
Lea Ružanović, Fran Rebrina, Marina Vilenica, Kristian Medak, Martin H. Entling, Andreja Brigić
Dispersal, either active or passive, plays a key role in community assembly during the colonisation of newly available habitats such as the dry riverbeds of intermittent rivers. These unstable environments are exposed to an ongoing colonisation process, often from adjacent riparian habitats that are local biodiversity hot spots. We aimed to identify the diversity, origin and colonisation pathways of terrestrial invertebrates in the dry bed of an intermittent Mediterranean river.
We sampled aerial and ground-dwelling invertebrates during the colonisation of dry riverbeds using cross-vane window traps and pitfall traps. Invertebrate communities were sampled in three habitat types of the intermittent karst Krčić River in Croatia: dry riverbed, riparian and upland habitat. For aerial invertebrates, we differentiated between diurnal and nocturnal colonists and between lateral and longitudinal colonists. All invertebrates were identified to order level, Carabidae, Araneae and Orthoptera to species. Environmental parameters were measured in each habitat.
Colonisation of the dry riverbed was primarily diurnal. Aerial invertebrates colonised both laterally, from the adjacent riparian habitat, and longitudinally, along the riverbed. Invertebrate catch was positively correlated with wind speed and direction, indicating the importance of passive dispersal by aerial plankton. The ground-dwelling invertebrate community exhibited rapid dry riverbed colonisation, with riparian habitats supporting the highest diversity and unique taxa. Taxonomic metrics showed different patterns for ground-dwelling invertebrates and each studied taxonomic group.
The observed patterns suggest that ground-dwelling Araneae and Carabidae colonised dry riverbed mostly through spillover from the riparian habitat. In contrast, Orthoptera probably colonised the dry riverbed from the upland habitat. Concurrent sampling of aerial and ground-dwelling colonists characterised responses that could not have been detected using a single method.
Our study demonstrates that multiple dispersal modes and source habitats are involved in the colonisation of the dry riverbed. Our results underline the importance to conserve riparian and upland areas along intermittent rivers as source habitats during the dry phase. Given the increase in stream intermittency due to climate change, the conservation and restoration of appropriate river landscapes could become more widely relevant in the future.
{"title":"Terrestrial Invertebrates Strike Back: Aerial and Ground-Based Colonisation of a Dry Riverbed","authors":"Lea Ružanović, Fran Rebrina, Marina Vilenica, Kristian Medak, Martin H. Entling, Andreja Brigić","doi":"10.1111/fwb.14379","DOIUrl":"https://doi.org/10.1111/fwb.14379","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Dispersal, either active or passive, plays a key role in community assembly during the colonisation of newly available habitats such as the dry riverbeds of intermittent rivers. These unstable environments are exposed to an ongoing colonisation process, often from adjacent riparian habitats that are local biodiversity hot spots. We aimed to identify the diversity, origin and colonisation pathways of terrestrial invertebrates in the dry bed of an intermittent Mediterranean river.</li>\u0000 \u0000 \u0000 <li>We sampled aerial and ground-dwelling invertebrates during the colonisation of dry riverbeds using cross-vane window traps and pitfall traps. Invertebrate communities were sampled in three habitat types of the intermittent karst Krčić River in Croatia: dry riverbed, riparian and upland habitat. For aerial invertebrates, we differentiated between diurnal and nocturnal colonists and between lateral and longitudinal colonists. All invertebrates were identified to order level, Carabidae, Araneae and Orthoptera to species. Environmental parameters were measured in each habitat.</li>\u0000 \u0000 \u0000 <li>Colonisation of the dry riverbed was primarily diurnal. Aerial invertebrates colonised both laterally, from the adjacent riparian habitat, and longitudinally, along the riverbed. Invertebrate catch was positively correlated with wind speed and direction, indicating the importance of passive dispersal by aerial plankton. The ground-dwelling invertebrate community exhibited rapid dry riverbed colonisation, with riparian habitats supporting the highest diversity and unique taxa. Taxonomic metrics showed different patterns for ground-dwelling invertebrates and each studied taxonomic group.</li>\u0000 \u0000 \u0000 <li>The observed patterns suggest that ground-dwelling Araneae and Carabidae colonised dry riverbed mostly through spillover from the riparian habitat. In contrast, Orthoptera probably colonised the dry riverbed from the upland habitat. Concurrent sampling of aerial and ground-dwelling colonists characterised responses that could not have been detected using a single method.</li>\u0000 \u0000 \u0000 <li>Our study demonstrates that multiple dispersal modes and source habitats are involved in the colonisation of the dry riverbed. Our results underline the importance to conserve riparian and upland areas along intermittent rivers as source habitats during the dry phase. Given the increase in stream intermittency due to climate change, the conservation and restoration of appropriate river landscapes could become more widely relevant in the future.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110841","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}
Teo Delić, Špela Di Batista Borko, Ester Premate, Behare Rexhepi, Roman Alther, Mara Knüsel, Florian Malard, Dieter Weber, Fabio Stoch, Jean-François Flot, Cene Fišer, Florian Altermatt
Cryptic species are an important part of freshwater biodiversity, yet it remains unclear how these species integrate into communities from local to regional geographic scales. To protect biodiversity, particularly overlooked cryptic species, an accurate understanding of the underlying processes and adequate level of protection is needed.
We analysed patterns of syntopies (local co-occurrences) and sympatries (regional range overlap) to explore how the phylogenetic origin of cryptic species shapes biodiversity patterns. We hypothesised (i) that syntopies were more common among distantly than closely related cryptic species, and (ii) that the existing sympatries were an outcome of phylogenetic relatedness and dispersal.
The hypotheses were tested on a polyphyletic species complex of subterranean amphipod species (Niphargus rhenorhodanensis complex) by deploying molecular species delimitation, time-calibrated phylogenies, and co-occurrence analyses with probabilistic and generalised linear models (GLM).
The studied complex comprised 37–48 molecular operational taxonomic units (MOTUs) from nine different clades, with syntopies occurring at random or less frequently than expected. GLM indicated age of divergence did not predict species sympatries, although they emerged more frequently among MOTUs from different clades. Sympatries, however, emerged through dispersal, in MOTUs with large geographic ranges. These mostly overlapped at the foothills of the Alps, the Jura and the Central Massif.
We conclude that the observed spatial patterns are mainly driven by dispersal and presumably reflect the geographic circumstances of speciation. While species richness on a local scale may be an outcome of competition and dispersal, regional biodiversity patterns presumably arise through a clade-level cascade of historical events, including orogeny and climatic shifts.
{"title":"Phylogenetic Origin of Morphologically Cryptic Species Shapes Co-Occurrence and Sympatry Patterns","authors":"Teo Delić, Špela Di Batista Borko, Ester Premate, Behare Rexhepi, Roman Alther, Mara Knüsel, Florian Malard, Dieter Weber, Fabio Stoch, Jean-François Flot, Cene Fišer, Florian Altermatt","doi":"10.1111/fwb.70000","DOIUrl":"https://doi.org/10.1111/fwb.70000","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Cryptic species are an important part of freshwater biodiversity, yet it remains unclear how these species integrate into communities from local to regional geographic scales. To protect biodiversity, particularly overlooked cryptic species, an accurate understanding of the underlying processes and adequate level of protection is needed.</li>\u0000 \u0000 \u0000 <li>We analysed patterns of syntopies (local co-occurrences) and sympatries (regional range overlap) to explore how the phylogenetic origin of cryptic species shapes biodiversity patterns. We hypothesised (i) that syntopies were more common among distantly than closely related cryptic species, and (ii) that the existing sympatries were an outcome of phylogenetic relatedness and dispersal.</li>\u0000 \u0000 \u0000 <li>The hypotheses were tested on a polyphyletic species complex of subterranean amphipod species (<i>Niphargus rhenorhodanensis</i> complex) by deploying molecular species delimitation, time-calibrated phylogenies, and co-occurrence analyses with probabilistic and generalised linear models (GLM).</li>\u0000 \u0000 \u0000 <li>The studied complex comprised 37–48 molecular operational taxonomic units (MOTUs) from nine different clades, with syntopies occurring at random or less frequently than expected. GLM indicated age of divergence did not predict species sympatries, although they emerged more frequently among MOTUs from different clades. Sympatries, however, emerged through dispersal, in MOTUs with large geographic ranges. These mostly overlapped at the foothills of the Alps, the Jura and the Central Massif.</li>\u0000 \u0000 \u0000 <li>We conclude that the observed spatial patterns are mainly driven by dispersal and presumably reflect the geographic circumstances of speciation. While species richness on a local scale may be an outcome of competition and dispersal, regional biodiversity patterns presumably arise through a clade-level cascade of historical events, including orogeny and climatic shifts.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143121482","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":"Issue Information - Cover and Ed Board","authors":"","doi":"10.1111/fwb.14266","DOIUrl":"https://doi.org/10.1111/fwb.14266","url":null,"abstract":"","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/fwb.14266","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143120875","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}
Maria Dayanne Lima de Lucena, André Ribeiro-Martins, Lilian Casatti, Thiago Bernardi Vieira, Gabriel Lourenço Brejão, Fernando Rogério Carvalho, Thaisa Sala Michelan, Leandro Juen, Luciano Fogaça de Assis de Montag
The increasing environmental changes threatening the fish fauna of streams are driving a growing interest in understanding how sites and species contribute to diversity, as this is important information for decision-making related to the management and conservation of priority areas and species. The objective of this study was to understand how environmental factors, spatial distance between streams, land use, and land cover (landscape) may be associated with the uniqueness of fish assemblages in Amazonian streams.
We sampled fish assemblages and characterised environmental conditions in 29 streams within and around the Tapajós River basin, near the Amazon National Park in Brazil. Each stream was studied along a 150-m stretch.
The variables associated with the local contribution to beta diversity (LCBD) were vegetation cover and the presence of refuges. Streams inside and outside the park showed similar contributions to beta diversity. Species richness and abundance showed a negative relationship with LCBD, suggesting that unique sites tended to have few species and low abundance. The species that contributed most to beta diversity (SCBD) had intermediate occurrence, high abundance, and non-marginal niches. We did not observe an effect of niche breadth on SCBD, as both generalist and specialist species contributed equally to beta diversity.
Our findings underscore the role of environmental variables in ecological uniqueness. Sites unique in species composition may also exhibit low species richness and abundance.
Our study demonstrates the importance of environmental variables in conserving biodiversity in Amazonian streams in the face of environmental changes. By examining the contributions of sites and species, we highlight the importance of considering habitat quality and uniqueness in protecting these ecosystems against the challenges of global change.
{"title":"Assessing Site and Species Associations With Beta Diversity of Fish Assemblages in Amazonian Streams","authors":"Maria Dayanne Lima de Lucena, André Ribeiro-Martins, Lilian Casatti, Thiago Bernardi Vieira, Gabriel Lourenço Brejão, Fernando Rogério Carvalho, Thaisa Sala Michelan, Leandro Juen, Luciano Fogaça de Assis de Montag","doi":"10.1111/fwb.70001","DOIUrl":"https://doi.org/10.1111/fwb.70001","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>The increasing environmental changes threatening the fish fauna of streams are driving a growing interest in understanding how sites and species contribute to diversity, as this is important information for decision-making related to the management and conservation of priority areas and species. The objective of this study was to understand how environmental factors, spatial distance between streams, land use, and land cover (landscape) may be associated with the uniqueness of fish assemblages in Amazonian streams.</li>\u0000 \u0000 \u0000 <li>We sampled fish assemblages and characterised environmental conditions in 29 streams within and around the Tapajós River basin, near the Amazon National Park in Brazil. Each stream was studied along a 150-m stretch.</li>\u0000 \u0000 \u0000 <li>The variables associated with the local contribution to beta diversity (LCBD) were vegetation cover and the presence of refuges. Streams inside and outside the park showed similar contributions to beta diversity. Species richness and abundance showed a negative relationship with LCBD, suggesting that unique sites tended to have few species and low abundance. The species that contributed most to beta diversity (SCBD) had intermediate occurrence, high abundance, and non-marginal niches. We did not observe an effect of niche breadth on SCBD, as both generalist and specialist species contributed equally to beta diversity.</li>\u0000 \u0000 \u0000 <li>Our findings underscore the role of environmental variables in ecological uniqueness. Sites unique in species composition may also exhibit low species richness and abundance.</li>\u0000 \u0000 \u0000 <li>Our study demonstrates the importance of environmental variables in conserving biodiversity in Amazonian streams in the face of environmental changes. By examining the contributions of sites and species, we highlight the importance of considering habitat quality and uniqueness in protecting these ecosystems against the challenges of global change.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119545","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}
<div> <p> </p><ol> <li>Non-native crayfish are among the most widespread aquatic invasive species worldwide. High densities of crayfish in lakes can potentially cause complete loss of macrophytes through herbivory, physical destruction, shading by suspension of sediments and nutrient release facilitating phytoplankton, thus altering ecosystem state and functions. However, lower crayfish densities may affect different macrophyte species in different ways, thus altering competition between macrophyte species with different growth forms. We hypothesize that high crayfish densities can completely destroy submerged macrophyte communities and shift systems into more turbid conditions whereas low crayfish densities can promote low-growing macrophytes that compete with canopy-forming species.</li> <li>To test these hypotheses, we applied three different densities (2, 4, 8 crayfish m<sup>−2</sup>) of the invasive crayfish <i>Procambarus clarkii</i> and a control (no crayfish) to 36 mesocosms of monocultures and mixed stands of low-growing and canopy-forming submerged macrophytes for 60 days. We measured concentrations of nutrients, suspended solids, phytoplankton and periphyton and above- and belowground biomass of low-growing <i>Vallisneria natans</i> and canopy-forming <i>Hydrilla verticillata</i>.</li> <li>In addition, we conducted a meta-analysis of crayfish impacts on macrophytes to compare effect sizes between different crayfish densities. Using data from published studies, we derived the relationship between crayfish density and crayfish-induced reductions in macrophyte abundance.</li> <li>Our meta-analysis revealed a significant decline of macrophytes with increasing crayfish densities. In line with existing studies, high crayfish densities caused a strong loss of both low-growing and canopy-forming macrophytes and increased nutrient concentrations, phytoplankton biomass and suspended sediment, thus favouring an ecosystem shift to more turbid conditions. Low and medium crayfish densities reduced macrophyte biomass similarly for both species in monocultures. However, in mixed cultures, low crayfish densities (2 crayfish m<sup>−2</sup>) reduced the above- and belowground biomass of the canopy-forming <i>H. verticillata</i> more than that of low-growing <i>V. natans</i>, supporting our hypothesis. This support of low-growing macrophytes occurred despite a temporal facilitation of shading by increased periphyton biomass.</li> <li>Our results show that the impact of crayfish invasions on aquatic ecosystems is strongly dependent on their density. High densities facilitate the loss of macrophytes and increase the likelihood of ecosystem collapse into a turbid state. However, low densities can provide a competitive advantage to low
{"title":"Contrasting Effects of Increasing Invasive Crayfish Densities on Competing Submerged Macrophytes in Shallow Lakes","authors":"Lei Li, Sabine Hilt, Mingming Ding","doi":"10.1111/fwb.14383","DOIUrl":"https://doi.org/10.1111/fwb.14383","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Non-native crayfish are among the most widespread aquatic invasive species worldwide. High densities of crayfish in lakes can potentially cause complete loss of macrophytes through herbivory, physical destruction, shading by suspension of sediments and nutrient release facilitating phytoplankton, thus altering ecosystem state and functions. However, lower crayfish densities may affect different macrophyte species in different ways, thus altering competition between macrophyte species with different growth forms. We hypothesize that high crayfish densities can completely destroy submerged macrophyte communities and shift systems into more turbid conditions whereas low crayfish densities can promote low-growing macrophytes that compete with canopy-forming species.</li>\u0000 \u0000 \u0000 <li>To test these hypotheses, we applied three different densities (2, 4, 8 crayfish m<sup>−2</sup>) of the invasive crayfish <i>Procambarus clarkii</i> and a control (no crayfish) to 36 mesocosms of monocultures and mixed stands of low-growing and canopy-forming submerged macrophytes for 60 days. We measured concentrations of nutrients, suspended solids, phytoplankton and periphyton and above- and belowground biomass of low-growing <i>Vallisneria natans</i> and canopy-forming <i>Hydrilla verticillata</i>.</li>\u0000 \u0000 \u0000 <li>In addition, we conducted a meta-analysis of crayfish impacts on macrophytes to compare effect sizes between different crayfish densities. Using data from published studies, we derived the relationship between crayfish density and crayfish-induced reductions in macrophyte abundance.</li>\u0000 \u0000 \u0000 <li>Our meta-analysis revealed a significant decline of macrophytes with increasing crayfish densities. In line with existing studies, high crayfish densities caused a strong loss of both low-growing and canopy-forming macrophytes and increased nutrient concentrations, phytoplankton biomass and suspended sediment, thus favouring an ecosystem shift to more turbid conditions. Low and medium crayfish densities reduced macrophyte biomass similarly for both species in monocultures. However, in mixed cultures, low crayfish densities (2 crayfish m<sup>−2</sup>) reduced the above- and belowground biomass of the canopy-forming <i>H. verticillata</i> more than that of low-growing <i>V. natans</i>, supporting our hypothesis. This support of low-growing macrophytes occurred despite a temporal facilitation of shading by increased periphyton biomass.</li>\u0000 \u0000 \u0000 <li>Our results show that the impact of crayfish invasions on aquatic ecosystems is strongly dependent on their density. High densities facilitate the loss of macrophytes and increase the likelihood of ecosystem collapse into a turbid state. However, low densities can provide a competitive advantage to low","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143117160","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}
Oscar Alberto Rojas-Castillo, Ali Hakimzadeh, Leho Tedersoo, Dean Jacobsen, Sebastian Kepfer-Rojas
{"title":"The Impact of Oil Palm Plantations and Pastures on Benthic Prokaryotic and Fungal Communities in Tropical Streams","authors":"Oscar Alberto Rojas-Castillo, Ali Hakimzadeh, Leho Tedersoo, Dean Jacobsen, Sebastian Kepfer-Rojas","doi":"10.1111/fwb.14376","DOIUrl":"https://doi.org/10.1111/fwb.14376","url":null,"abstract":"<p>\u0000 \u0000 </p>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/fwb.14376","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143115665","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}
Peter. M. Kiffney, Beth L. Sanderson, Karl B. Veggerby, Jesse James Lamb, Gordon A. Axel
{"title":"Water Temperature, Prey Concentration and Salmonid Density Influence Daily Growth of Wild Juvenile Salmonids in Tributaries of the Upper Salmon River, Idaho (USA)","authors":"Peter. M. Kiffney, Beth L. Sanderson, Karl B. Veggerby, Jesse James Lamb, Gordon A. Axel","doi":"10.1111/fwb.14380","DOIUrl":"https://doi.org/10.1111/fwb.14380","url":null,"abstract":"<p>\u0000 \u0000 </p>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/fwb.14380","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143115086","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}
Mary M. Sears, Randall A. Myers, Mitchell T. Nisbet, M. Travis Tidwell, Matthew J. Troia
Understanding which species can persist in human-modified environments is essential to biodiversity conservation in the Anthropocene. In urbanised environments, many stressors limit the persistence of imperilled native species via impacts on the abiotic and biotic environment. Habitat restoration followed by reintroduction of native species may be an effective strategy to maintain or even regenerate biodiversity in urbanised environments, but few studies have assessed these two conservation strategies concomitantly in urban freshwater ecosystems.
We assessed short-term population dynamics and habitat associations of an endemic species of conservation concern, Guadalupe bass (Micropterus treculii, ‘GB’), that was reintroduced in a restored urbanised riverscape already occupied by a generalist congener, largemouth bass (M. salmoides, ‘LMB’). We performed four seasonal surveys of habitat association and one capture-mark-recapture survey of the two species at eight sites distributed along a 17 km reach of the San Antonio River within San Antonio, Texas—the seventh largest city in the United States.
Detection of multiple size classes at all eight sites indicated that reintroduced GB have dispersed throughout this riverscape and are naturally recruiting. Juvenile GB were associated with restored riffles and transitioned to pools as adults—an ontogenetic habitat shift documented in rivers draining natural landscapes elsewhere in the GB native range. By contrast, juvenile and adult LMB were associated with pool habitats. Our results indicated that the construction of riffle habitats along this restored riverscape provide essential habitat for juvenile GB that was unavailable prior to restoration. Habitat overlap of adult bass indicated the potential for competition between the two species; however, GB body condition did not vary with LMB abundance across sites or seasons.
Next, we assessed long-term stressors by comparing dispersal barriers, hydrologic alteration, pollution proxies and fish kill frequencies in the urbanised restored riverscape to minimally-impacted riverscapes throughout the native GB range. The urbanised restored riverscape was subject to more barriers, flashier hydrology and more pollution; however, these stressors did not translate to more frequently-documented fish kills in our study.
We showed that restoration of instream habitat followed by reintroduction of native species enhanced urbanised biodiversity. Monitoring population responses to multiple urbanised stressors and mitigating those that threaten the long-term persistence of reintroduced species remains important.
{"title":"Assessing Short- and Long-Term Anthropogenic Threats to a Reintroduced Fish in a Restored Urban Riverscape","authors":"Mary M. Sears, Randall A. Myers, Mitchell T. Nisbet, M. Travis Tidwell, Matthew J. Troia","doi":"10.1111/fwb.14377","DOIUrl":"https://doi.org/10.1111/fwb.14377","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Understanding which species can persist in human-modified environments is essential to biodiversity conservation in the Anthropocene. In urbanised environments, many stressors limit the persistence of imperilled native species via impacts on the abiotic and biotic environment. Habitat restoration followed by reintroduction of native species may be an effective strategy to maintain or even regenerate biodiversity in urbanised environments, but few studies have assessed these two conservation strategies concomitantly in urban freshwater ecosystems.</li>\u0000 \u0000 \u0000 <li>We assessed <i>short-term</i> population dynamics and habitat associations of an endemic species of conservation concern, Guadalupe bass (<i>Micropterus treculii</i>, ‘GB’), that was reintroduced in a restored urbanised riverscape already occupied by a generalist congener, largemouth bass (<i>M. salmoides</i>, ‘LMB’). We performed four seasonal surveys of habitat association and one capture-mark-recapture survey of the two species at eight sites distributed along a 17 km reach of the San Antonio River within San Antonio, Texas—the seventh largest city in the United States.</li>\u0000 \u0000 \u0000 <li>Detection of multiple size classes at all eight sites indicated that reintroduced GB have dispersed throughout this riverscape and are naturally recruiting. Juvenile GB were associated with restored riffles and transitioned to pools as adults—an ontogenetic habitat shift documented in rivers draining natural landscapes elsewhere in the GB native range. By contrast, juvenile and adult LMB were associated with pool habitats. Our results indicated that the construction of riffle habitats along this restored riverscape provide essential habitat for juvenile GB that was unavailable prior to restoration. Habitat overlap of adult bass indicated the potential for competition between the two species; however, GB body condition did not vary with LMB abundance across sites or seasons.</li>\u0000 \u0000 \u0000 <li>Next, we assessed <i>long-term</i> stressors by comparing dispersal barriers, hydrologic alteration, pollution proxies and fish kill frequencies in the urbanised restored riverscape to minimally-impacted riverscapes throughout the native GB range. The urbanised restored riverscape was subject to more barriers, flashier hydrology and more pollution; however, these stressors did not translate to more frequently-documented fish kills in our study.</li>\u0000 \u0000 \u0000 <li>We showed that restoration of instream habitat followed by reintroduction of native species enhanced urbanised biodiversity. Monitoring population responses to multiple urbanised stressors and mitigating those that threaten the long-term persistence of reintroduced species remains important.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143113600","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":"Effects of Deforestation-Induced Warming on the Thermal Tolerance of an African Clariid Catfish","authors":"Erin K. Francispillai, Lauren J. Chapman","doi":"10.1111/fwb.14375","DOIUrl":"https://doi.org/10.1111/fwb.14375","url":null,"abstract":"<p>\u0000 \u0000 </p>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/fwb.14375","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143113601","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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