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Scharnweber K, Scholz C, Schippenbeil V, Milano S, Hühn D. Effects of mining activities on fish communities and food web dynamics in a lowland river. Ecol Evol 2024; 14:e11111. [PMID: 38476699 PMCID: PMC10928357 DOI: 10.1002/ece3.11111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 01/24/2024] [Accepted: 02/21/2024] [Indexed: 03/14/2024] Open
Abstract
Fish communities of streams and rivers might be substantially subsidized by terrestrial insects that fall into the water. Although such animal-mediated fluxes are increasingly recognized, little is known about how anthropogenic perturbations may influence the strength of such exchanges. Intense land use, such as lignite mining, may impact a river ecosystem due to the flocculation of iron (III) oxides, thus altering food web dynamics. We compared sections of the Spree River in North-East Germany that were greatly influenced by iron oxides with sections located downstream of a dam where passive remediation technologies are applied. Compared to locations downstream of the dam, the abundance of benthic macroinvertebrates at locations of high iron concentrations upstream of the dam was significantly reduced. Similarly, catch per unit effort of all fish was significantly higher in locations downstream of the dam compared to locations upstream of the dam, and the condition of juvenile and adult piscivorous pike Esox lucius was significantly lower in sections of high iron concentrations. Using an estimate of short-term (i.e., metabarcoding of the gut content) as well as longer-term (i.e., hydrogen stable isotopes) resource use, we could demonstrate that the three most abundant fish species, perch Perca fluviatilis, roach Rutilus rutilus, and bleak Alburnus alburnus, received higher contributions of terrestrial insects to their diet at locations of high iron concentration. In summary, lotic food webs upstream and downstream of the dam greatly differed in the overall structure with respect to the energy available for the highest tropic levels and the contribution of terrestrial insects to the diet of omnivorous fish. Therefore, human-induced environmental perturbations, such as river damming and mining activities, represent strong pressures that can alter the flow of energy between aquatic and terrestrial systems, indicating a broad impact on the landscape level.
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Affiliation(s)
- Kristin Scharnweber
- Plant Ecology and Nature ConservationUniversity of PotsdamPotsdamGermany
- Ecological Research Station ReesUniversity of CologneRees‐BienenGermany
| | - Carolin Scholz
- Plant Ecology and Nature ConservationUniversity of PotsdamPotsdamGermany
- Leibniz Institute for Zoo and Wildlife Research, Evolutionary EcologyBerlinGermany
| | - Victor Schippenbeil
- Faculty of Mathematics and Science II, Geography DepartmentHumboldt‐Universität zu BerlinBerlinGermany
| | - Stefania Milano
- Leibniz Institute for Zoo and Wildlife Research, Evolutionary EcologyBerlinGermany
| | - Daniel Hühn
- Potsdam Institute of Inland FisheriesPotsdamGermany
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2
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Andersson ML, Scharnweber K, Eklöv P. The interaction between metabolic rate, habitat choice, and resource use in a polymorphic freshwater species. Ecol Evol 2022; 12:e9129. [PMID: 35923943 PMCID: PMC9339753 DOI: 10.1002/ece3.9129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 06/23/2022] [Accepted: 06/27/2022] [Indexed: 11/12/2022] Open
Abstract
Resource polymorphism is common across taxa and can result in alternate ecotypes with specific morphologies, feeding modes, and behaviors that increase performance in a specific habitat. This can result in high intraspecific variation in the expression of specific traits and the extent to which these traits are correlated within a single population. Although metabolic rate influences resource acquisition and the overall pace of life of individuals it is not clear how metabolic rate interacts with the larger suite of traits to ultimately determine individual fitness.We examined the relationship between metabolic rates and the major differences (habitat use, morphology, and resource use) between littoral and pelagic ecotypes of European perch (Perca fluviatilis) from a single lake in Central Sweden.Standard metabolic rate (SMR) was significantly higher in pelagic perch but did not correlate with resource use or morphology. Maximum metabolic rate (MMR) was not correlated with any of our explanatory variables or with SMR. Aerobic scope (AS) showed the same pattern as SMR, differing across habitats, but contrary to expectations, was lower in pelagic perch.This study helps to establish a framework for future experiments further exploring the drivers of intraspecific differences in metabolism. In addition, since metabolic rates scale with temperature and determine predator energy requirements, our observed differences in SMR across habitats will help determine ecotype-specific vulnerabilities to climate change and differences in top-down predation pressure across habitats.
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Affiliation(s)
- Matilda L. Andersson
- Department of Ecology and GeneticsUppsala UniversityUppsalaSweden
- Department of Aquatic Sciences and AssessmentSwedish University of Agricultural SciencesUppsalaSweden
| | - Kristin Scharnweber
- Department of Ecology and GeneticsUppsala UniversityUppsalaSweden
- Department of Plant Ecology and Nature ConservationUniversity of PotsdamPotsdamGermany
| | - Peter Eklöv
- Department of Ecology and GeneticsUppsala UniversityUppsalaSweden
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Berkhout BW, Morozov A. Assassin snails (Anentome helena) as a biological model for exploring the effects of individual specialisation within generalist predators. PLoS One 2022; 17:e0264996. [PMID: 35286318 PMCID: PMC8920249 DOI: 10.1371/journal.pone.0264996] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 02/21/2022] [Indexed: 11/26/2022] Open
Abstract
Quantifying feeding behaviour of generalist predators at the population and individual levels is crucial for understanding the structure and functioning of food webs. Individual predator/consumer feeding niches can be significantly narrower than that of the population across animal taxa. In such species, the population of a generalist predator becomes essentially an ensemble of specialist individuals and this often highly affects the dynamics of the prey-predator interactions. Currently, few experimental systems exist that are both easily technically manipulated in a lab and are reliable to accurately assess effects of individual specialisation within generalist predators. Here we argue that a freshwater predaceous snail, Anentome helena (also known as an ‘assassin snail’), is a convenient and reliable experimental system to study feeding of a generalist predator on multiple food types which exhibits well-pronounced specialisation of foraging individuals. Using A. helena we experimentally test: (i) how relative prey abundances in the environment affect the feeding patterns, (ii) whether the feeding patterns are consistent over the duration of the experimental period, and (iii) compare the feeding niche breadth of individuals to that of the laboratory population. By offering four different prey snail species, at a range of relative abundances, we show that there are consistent patterns in feeding. Importantly, the consumption of each prey was independent of the relative abundance at which they were present. Individual predators showed selectivity to a particular prey, i.e. the population of assassin snails seems to be formed of individuals that specialise on different prey. Our findings would contribute to the recent revision and the ongoing debate on the classification of predator species into generalists and specialists.
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Affiliation(s)
- Boris W. Berkhout
- Department of Genetics and Genome Biology, University of Leicester, United Kingdom
- * E-mail:
| | - Andrew Morozov
- Department of Mathematics, University of Leicester, United Kingdom
- Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russia
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4
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Scharnweber K, Andersson ML, Chaguaceda F, Eklöv P. Intraspecific differences in metabolic rates shape carbon stable isotope trophic discrimination factors of muscle tissue in the common teleost Eurasian perch ( Perca fluviatilis). Ecol Evol 2021; 11:9804-9814. [PMID: 34306663 PMCID: PMC8293782 DOI: 10.1002/ece3.7809] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 06/02/2021] [Indexed: 11/09/2022] Open
Abstract
Stable isotopes represent a unique approach to provide insights into the ecology of organisms. δ13C and δ15N have specifically been used to obtain information on the trophic ecology and food-web interactions. Trophic discrimination factors (TDF, Δ13C and Δ15N) describe the isotopic fractionation occurring from diet to consumer tissue, and these factors are critical for obtaining precise estimates within any application of δ13C and δ15N values. It is widely acknowledged that metabolism influences TDF, being responsible for different TDF between tissues of variable metabolic activity (e.g., liver vs. muscle tissue) or species body size (small vs. large). However, the connection between the variation of metabolism occurring within a single species during its ontogeny and TDF has rarely been considered.Here, we conducted a 9-month feeding experiment to report Δ13C and Δ15N of muscle and liver tissues for several weight classes of Eurasian perch (Perca fluviatilis), a widespread teleost often studied using stable isotopes, but without established TDF for feeding on a natural diet. In addition, we assessed the relationship between the standard metabolic rate (SMR) and TDF by measuring the oxygen consumption of the individuals.Our results showed a significant negative relationship of SMR with Δ13C, and a significant positive relationship of SMR with Δ15N of muscle tissue, but not with TDF of liver tissue. SMR varies inversely with size, which translated into a significantly different TDF of muscle tissue between size classes.In summary, our results emphasize the role of metabolism in shaping-specific TDF (i.e., Δ13C and Δ15N of muscle tissue) and especially highlight the substantial differences between individuals of different ontogenetic stages within a species. Our findings thus have direct implications for the use of stable isotope data and the applications of stable isotopes in food-web studies.
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Affiliation(s)
- Kristin Scharnweber
- Department of Ecology and Genetics; LimnologyUppsala UniversityUppsalaSweden
- Department of Plant Ecology and Nature ConservationUniversity of PotsdamPotsdamGermany
| | | | - Fernando Chaguaceda
- Department of Ecology and Genetics; LimnologyUppsala UniversityUppsalaSweden
- Present address:
Department of Aquatic Sciences and AssessmentSwedish University of Agricultural SciencesUppsalaSweden
| | - Peter Eklöv
- Department of Ecology and Genetics; LimnologyUppsala UniversityUppsalaSweden
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Dijoux S, Boukal DS. Community structure and collapses in multichannel food webs: Role of consumer body sizes and mesohabitat productivities. Ecol Lett 2021; 24:1607-1618. [PMID: 34036707 DOI: 10.1111/ele.13772] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/19/2021] [Accepted: 04/12/2021] [Indexed: 11/30/2022]
Abstract
Multichannel food webs are shaped by the ability of apex predators to link asymmetric energy flows in mesohabitats differing in productivity and community traits. While body size is a fundamental trait underlying life histories and demography, its implications for structuring multichannel food webs are unexplored. To fill this gap, we develop a model that links population responses to predation, and resource availability to community-level patterns, using a tri-trophic food web model with two populations of intermediate consumers and a size-selective top predator. We show that asymmetries in mesohabitat productivities and consumer body sizes drive food web structure, merging previously separate theory on apparent competition and emergent Allee effects (i.e. abrupt population collapses) of top predators. Our results yield theoretical support for empirically observed stability of asymmetric multichannel food webs and discover three novel types of emergent Allee effects involving intermediate consumers, multiple populations or multiple alternative stable states.
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Affiliation(s)
- Samuel Dijoux
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic.,Czech Academy of Sciences, Biology Centre, Institute of Entomology, České Budějovice, Czech Republic
| | - David S Boukal
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic.,Czech Academy of Sciences, Biology Centre, Institute of Entomology, České Budějovice, Czech Republic
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Scharnweber K, Chaguaceda F, Eklöv P. Fatty acid accumulation in feeding types of a natural freshwater fish population. Oecologia 2021; 196:53-63. [PMID: 33900451 PMCID: PMC8139920 DOI: 10.1007/s00442-021-04913-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 03/30/2021] [Indexed: 01/12/2023]
Abstract
Fatty acids are widely used to study trophic interactions in food web assemblages. Generally, it is assumed that there is a very small modification of fatty acids from one trophic step to another, making them suitable as trophic biomarkers. However, recent literature provides evidence that many fishes possess genes encoding enzymes with a role in bioconversion, thus the capability for bioconversion might be more widespread than previously assumed. Nonetheless, empirical evidence for biosynthesis occurring in natural populations remains scarce. In this study, we investigated different feeding types of perch (Perca fluviatilis) that are specialized on specific resources with different levels of highly unsaturated fatty acids (HUFAs), and analyzed the change between HUFA proportions in perch muscle tissue compared to their resources. Perch showed matching levels to their resources for EPA, but ARA and especially DHA were accumulated. Compound-specific stable isotope analyses helped us to identify the origin of HUFA carbon. Our results suggest that perch obtain a substantial amount of DHA via bioconversion when feeding on DHA-poor benthic resources. Thus, our data indicate the capability of bioconversion of HUFAs in a natural freshwater fish population.
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Affiliation(s)
- Kristin Scharnweber
- Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden.
- Plant Ecology and Nature Conservation, University of Potsdam, Potsdam, Germany.
| | - Fernando Chaguaceda
- Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Peter Eklöv
- Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden
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Lang I, Evangelista C, Everts RM, Loot G, Cucherousset J. Stable resource polymorphism along the benthic littoral-pelagic axis in an invasive crayfish. Ecol Evol 2020; 10:2650-2660. [PMID: 32185009 PMCID: PMC7069303 DOI: 10.1002/ece3.6095] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 01/14/2020] [Accepted: 01/16/2020] [Indexed: 01/08/2023] Open
Abstract
Although intraspecific variability is now widely recognized as affecting evolutionary and ecological processes, our knowledge on the importance of intraspecific variability within invasive species is still limited. This is despite the fact that understanding the linkage between within-population morphological divergences and the use of different trophic or spatial resources (i.e., resource polymorphism) can help to better predict their ecological impacts on recipient ecosystems. Here, we quantified the extent of resource polymorphism within populations of a worldwide invasive crayfish species, Procambarus clarkii, in 16 lake populations by comparing their trophic (estimated using stable isotope analyses) and morphological characteristics between individuals from the littoral and pelagic habitats. Our results first demonstrated that crayfish occured in both littoral and pelagic habitats of seven lakes and that the use of pelagic habitat was associated with increased abundance of littoral crayfish. We then found morphological (i.e., body and chelae shapes) and trophic divergence (i.e., reliance on littoral carbon) among individuals from littoral and pelagic habitats, highlighting the existence of resource polymorphism in invasive populations. There was no genetic differentiation between individuals from the two habitats, implying that this resource polymorphism was stable (i.e., high gene flow between individuals). Finally, we demonstrated that a divergent adaptive process was responsible for the morphological divergence in body and chela shapes between habitats while difference in littoral reliance neutrally evolved under genetic drift. These findings demonstrated that invasive P. clarkii can display strong within-population phenotypic variability in recent populations, and this could lead to contrasting ecological impacts between littoral and pelagic individuals.
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Affiliation(s)
- Iris Lang
- Laboratoire Évolution et Diversité Biologique (EDB UMR 5174)Université de Toulouse, CNRS, UPSToulouseFrance
| | - Charlotte Evangelista
- Laboratoire Évolution et Diversité Biologique (EDB UMR 5174)Université de Toulouse, CNRS, UPSToulouseFrance
- Department of BiosciencesCentre for Ecological and Evolutionary Synthesis (CEES)University of OsloOsloNorway
| | - Rebecca Marie Everts
- Laboratoire Évolution et Diversité Biologique (EDB UMR 5174)Université de Toulouse, CNRS, UPSToulouseFrance
| | - Géraldine Loot
- Laboratoire Évolution et Diversité Biologique (EDB UMR 5174)Université de Toulouse, CNRS, UPSToulouseFrance
| | - Julien Cucherousset
- Laboratoire Évolution et Diversité Biologique (EDB UMR 5174)Université de Toulouse, CNRS, UPSToulouseFrance
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