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Yan K, Guo F, Kainz MJ, Bunn SE, Li F, Gao W, Ouyang X, Zhang Y. Increasing water nutrient reduces the availability of high-quality food resources for aquatic consumers and consequently simplifies river food webs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 929:172706. [PMID: 38657799 DOI: 10.1016/j.scitotenv.2024.172706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 04/01/2024] [Accepted: 04/21/2024] [Indexed: 04/26/2024]
Abstract
While eutrophication has led to serious habitat degradation and biotic shifts in freshwater ecosystems, most current studies have focused on changes in community assemblages, with few considering the effect of eutrophication on food webs. We conducted a field study in subtropical headwater streams with a gradient of water nutrient levels to examine the effect of increasing water nutrients on food webs by using the long-chain polyunsaturated fatty acid eicosapentaenoic acid (EPA) as a measure of the nutritional quality of food. Basal food resources (macrophytes, submerged leaf litter, and periphyton), and aquatic consumers (macroinvertebrates and fish) were collected, and their fatty acid (FA) profiles were analyzed. Our results showed that periphyton was the dominant source of EPA for macroinvertebrates and fish, and a high-quality resource for consumers. As water nutrient concentrations increased, nutritional quality of periphyton significantly decreased and, in turn, the correlation between FA profiles of periphyton and macroinvertebrates declined. However, periphyton FA profiles did not account for the variability of fish FA, which may be induced by the increasing proportions of omnivorous fish in eutrophic streams that derived EPA from other sources. Further, the reduced periphyton EPA was associated with decreased trophic links and simplified stream food webs. Our study highlights the importance of high-quality food resources for aquatic food webs as water nutrients increased in stream ecosystems and provides a nutritional perspective to understand the mechanisms how eutrophication affects aquatic ecosystems.
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Affiliation(s)
- Keheng Yan
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China; Guangdong Basic Research Center of Excellence for Ecological Security and Green Development, Guangzhou 510006, China
| | - Fen Guo
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China; Guangdong Basic Research Center of Excellence for Ecological Security and Green Development, Guangzhou 510006, China.
| | - Martin J Kainz
- WasserCluster Lunz - Biologische Station, Lunz am See, Austria; Danube University Krems, Aquatic Ecosystem Research and -Health, 3500 Krems, Austria
| | - Stuart E Bunn
- Australian Rivers Institute, Griffith University, Nathan, Qld, Australia
| | - Feilong Li
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China; Guangdong Basic Research Center of Excellence for Ecological Security and Green Development, Guangzhou 510006, China
| | - Wei Gao
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China; Guangdong Basic Research Center of Excellence for Ecological Security and Green Development, Guangzhou 510006, China
| | - Xiaoguang Ouyang
- Research Centre of Ecology & Environment for Coastal Area and Deep Sea, Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
| | - Yuan Zhang
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China; Guangdong Basic Research Center of Excellence for Ecological Security and Green Development, Guangzhou 510006, China
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2
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Huang J, Guo F, Burford MA, Kainz M, Li F, Gao W, Ouyang X, Zhang Y. How do small dams alter river food webs? A food quality perspective along the aquatic food web continuum. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 355:120501. [PMID: 38437746 DOI: 10.1016/j.jenvman.2024.120501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 02/23/2024] [Accepted: 02/23/2024] [Indexed: 03/06/2024]
Abstract
Damming of rivers poses a significant threat to freshwater ecosystems. Previous studies about the impact of damming on river ecosystems have mostly focused on large dams, with the impact of small dams largely unknown. Further, while the impacts of dams on aquatic communities have been widely studied, the effect on energy flow across river food webs remains unclear. In recent years, long-chain polyunsaturated fatty acid analysis (LC-PUFA) has emerged as a promising technique for assessing food quality and trophic interactions. In this study, LC-PUFA was applied to explore the nutritional effects of small dams on river food webs. A field investigation was conducted at upstream and downstream areas of three small dams in the headwaters of Dongjiang River, China, to evaluate the impact of small dams on the nutritional quality of basal food sources, and their consequent impacts on aquatic consumers and trophic links. Basal food sources (i.e., submerged leaves, macrophytes and periphyton) and aquatic consumers (i.e., macroinvertebrates and fish) were collected, and their fatty acid (FA) composition was measured. Our results showed that periphyton, rather than submerged leaves and macrophytes, was the primary high-quality food source for aquatic consumers, providing them with LC-PUFA, irrespective of whether sites were upstream or downstream. Damming the streams induced changes in aqueous nutrient concentrations (TP, PO4-P, DIN, and TN) from upstream to downstream of the dams, leading to significant variation in periphyton FA content. Compared with periphyton collected at downstream sites, periphyton at upstream sites contained higher LC-PUFA, but lower short-chain PUFA. Differences in periphyton LC-PUFA between the upstream and downstream areas of dams were reflected in the FA profiles of invertebrate grazers and filterers, and further transferred to fish. Furthermore, decreased periphyton nutritional quality at the downstream of the dams was one of the reasons for the simplification of stream food webs. Our results indicated that small dams negatively affected food webs, emphasizing the importance of high-quality food sources for stream ecosystems. We suggest that the trophic integrity of river food webs hinges on the dietary availability of periphyton supplying physiologically highly required nutrients for consumers and must thus not be compromised by damming of streams or other alterations.
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Affiliation(s)
- Juan Huang
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou, 510006, China; Guangdong Basic Research Center of Excellence for Ecological Security and Green Development in Guangdong-Hong Kong-Macao Greater Bay Area (GBA), School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, 510006, China
| | - Fen Guo
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou, 510006, China; Guangdong Basic Research Center of Excellence for Ecological Security and Green Development in Guangdong-Hong Kong-Macao Greater Bay Area (GBA), School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, 510006, China.
| | - Michele A Burford
- Australian Rivers Institute, Griffith University, Nathan, Qld, 4109, Australia
| | - Martin Kainz
- WasserCluster Lunz - Inter-University Centre for Aquatic Ecosystem Research, 3293 Lunz am See, Austria; Research lab for Aquatic Ecosystem Research and -Health, Danube University Krems, 3500 Krems an der Donau, Austria
| | - Feilong Li
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou, 510006, China; Guangdong Basic Research Center of Excellence for Ecological Security and Green Development in Guangdong-Hong Kong-Macao Greater Bay Area (GBA), School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, 510006, China
| | - Wei Gao
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou, 510006, China; Guangdong Basic Research Center of Excellence for Ecological Security and Green Development in Guangdong-Hong Kong-Macao Greater Bay Area (GBA), School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, 510006, China
| | - Xiaoguang Ouyang
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Yuan Zhang
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou, 510006, China; Guangdong Basic Research Center of Excellence for Ecological Security and Green Development in Guangdong-Hong Kong-Macao Greater Bay Area (GBA), School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, 510006, China
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3
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Yan K, Guo F, Kainz MJ, Li F, Gao W, Bunn SE, Zhang Y. The importance of omega-3 polyunsaturated fatty acids as high-quality food in freshwater ecosystems with implications of global change. Biol Rev Camb Philos Soc 2024; 99:200-218. [PMID: 37724488 DOI: 10.1111/brv.13017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 09/03/2023] [Accepted: 09/08/2023] [Indexed: 09/20/2023]
Abstract
Traditionally, trophic ecology research on aquatic ecosystems has focused more on the quantity of dietary energy flow within food webs rather than food quality and its effects on organisms at various trophic levels. Recent studies emphasize that food quality is central to consumer growth and reproduction, and the importance of food quality for aquatic ecosystems has become increasingly well recognized. It is timely to synthesise these findings and identify potential future research directions. We conducted a systematic review of omega-3 polyunsaturated fatty acids (ω3-PUFAs) as a crucial component of high-quality food sources in freshwater ecosystems to evaluate their impact on a variety of consumers, and explore the effects of global change on these high-quality food sources and their transfer to higher trophic consumers within and across ecosystems. In freshwater ecosystems, algae rich in ω3 long-chain PUFAs, such as diatoms, dinoflagellates and cryptophytes, represent important high-quality food sources for consumers, whereas cyanobacteria, green algae, terrestrial vascular plants and macrophytes low in ω3 long-chain PUFAs are low-quality food sources. High-quality ω3-PUFA-containing food sources usually lead to increased growth and reproduction of aquatic consumers, e.g. benthic invertebrates, zooplankton and fish, and also provide ω3 long-chain PUFAs to riparian terrestrial consumers via emergent aquatic insects. Consumers feeding on high-quality ω3-PUFA-containing foods in turn represent high-quality food for their own predators. However, the ω3-PUFA content of food sources is sensitive to global environmental changes. Warming, eutrophication, increased light intensity (e.g. from loss of riparian shading), and pollutants potentially inhibit the synthesis of algal ω3-PUFAs while at the same time promoting the growth of lower-quality foods, such as cyanobacteria and green algae. These factors combined could lead to a significant reduction in the availability of ω3-PUFAs for consumers and constrain their overall fitness. Although the effect of individual environmental factors on high-quality ω3-PUFA-containing food sources has been investigated, multiple environmental factors (e.g. climate change, human activities, pollution) will act in combination and any synergistic effects on aquatic food webs remain unclear. Identifying the sources and fate of ω3-PUFAs within and across ecosystems could represent an important approach to understand the impact of multiple environmental factors on trophic relationships and the implications for populations of freshwater and riparian consumers. Maintaining the availability of high-quality ω3-PUFA-containing food sources may also be key to mitigating freshwater biodiversity loss due to global change.
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Affiliation(s)
- Keheng Yan
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou, 510006, China
| | - Fen Guo
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou, 510006, China
| | - Martin J Kainz
- WasserCluster Lunz - Biologische Station, Lunz am See, 3293, Austria
- Danube University Krems, Research Lab for Aquatic Ecosystems and Health, Krems, 3500, Austria
| | - Feilong Li
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou, 510006, China
| | - Wei Gao
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou, 510006, China
| | - Stuart E Bunn
- Australian Rivers Institute, Griffith University, Nathan, Queensland, Australia
| | - Yuan Zhang
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou, 510006, China
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4
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Guo F, Fry B, Yan K, Huang J, Zhao Q, O'Mara K, Li F, Gao W, Kainz MJ, Brett MT, Bunn SE, Zhang Y. Assessment of the impact of dams on aquatic food webs using stable isotopes: Current progress and future challenges. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 904:167097. [PMID: 37716688 DOI: 10.1016/j.scitotenv.2023.167097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 09/10/2023] [Accepted: 09/13/2023] [Indexed: 09/18/2023]
Abstract
Dams have disrupted natural river systems worldwide and although population and community level effects on aquatic biota have been well documented, food web responses remain poorly understood and difficult to characterize. The application of stable isotope analysis (SIA) provides a means to assess the effect of dams on food webs. Here we review the effect of dams on aquatic food webs using SIA, aiming to detect knowledge gaps in the field of dam impacts on aquatic food webs and propose a conceptual framework to help formulate hypotheses about dam impacts on food webs guided by food web theory. Dams can affect aquatic food webs via two pathways: a bottom-up pathway with altered basal food sources and their transfer to consumers through changes in flow, nutrients, temperature and sediment, and a top-down pathway with consumer species composition altered mainly through habitat fragmentation and related physiochemical changes. Taking these mechanisms into consideration, the impact of dams on food web attributes derived from SIA was evaluated. These studies generally apply mixing models to determine how dams alter the dominant carbon sources supporting food webs, use δ15N to examine how dams alter food-chain length, or use Layman metrics of isotope variability to assess niche changes for invertebrate and fish assemblages. Most studies compare the patterns of SIA metrics spatially (e.g. upstream vs reservoir vs downstream of dams; regulated vs unregulated rivers) and temporally (before vs after dam construction), without explicit hypotheses and/or links to theoretical concepts of food webs. We propose several steps to make SIA studies of dam impacts more rigorous and enhance their potential for producing novel insights. Future studies should quantify the shape and strength of the effect of dams on SIA-measured food web response, be conducted at larger temporal and spatial scales (particularly along the river longitudinal continuum and the lateral connected ecosystems (e.g., floodplains)), and consider effects of dams on food web resilience and tipping points.
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Affiliation(s)
- Fen Guo
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China.
| | - Brian Fry
- Australian Rivers Institute, Griffith University, Nathan, Qld 4109, Australia
| | - Keheng Yan
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
| | - Juan Huang
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
| | - Qian Zhao
- Institute of Environment and Ecology, Shandong Normal University, Jinan 250358, China
| | - Kaitlyn O'Mara
- Australian Rivers Institute, Griffith University, Nathan, Qld 4109, Australia
| | - Feilong Li
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
| | - Wei Gao
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
| | - Martin J Kainz
- WasserCluster Lunz - Inter-University Centre for Aquatic Ecosystem Research, Lunz am See, Austria
| | - Michael T Brett
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
| | - Stuart E Bunn
- Australian Rivers Institute, Griffith University, Nathan, Qld 4109, Australia
| | - Yuan Zhang
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
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5
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Nair P, Miller CM, Fuiman LA. Tracing exploitation of egg boons: an experimental study using fatty acids and stable isotopes. J Exp Biol 2023; 226:jeb246247. [PMID: 37909269 DOI: 10.1242/jeb.246247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 10/23/2023] [Indexed: 11/03/2023]
Abstract
Coordinated spawning of marine animals releases millions of planktonic eggs into the environment, known as egg boons. Eggs are rich in essential fatty acids and may be an important lipid subsidy to egg consumers. Our aim was to validate the application of fatty acid and stable isotope tracers of egg consumption to potential egg consumers and to confirm egg consumption by the selected species. We conducted feeding experiments with ctenophores, crustaceans and fishes. We fed these animals a common diet of Artemia or a commercial feed (Otohime) and simulated egg boons for half of them by intermittently supplementing the common diet with red drum (Sciaenops ocellatus) eggs for 10-94 days. Controls did not receive eggs. Fatty acid profiles of consumers fed eggs were significantly different from those of controls 24 h after the last egg-feeding event. Consumers took on fatty acid characteristics of eggs. In fishes and ctenophores, fatty acid markers of egg consumption did not persist 2-5 days after the last egg-feeding event, but markers of egg consumption persisted in crustaceans for at least 5-10 days. Additionally, consumption of eggs, which had high values of δ15N, led to δ15N enrichment in crustaceans and a fish. We conclude that fatty acids and nitrogen stable isotope can be used as biomarkers of recent egg consumption in marine animals, validating their use for assessing exploitation of egg boons in nature.
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Affiliation(s)
- Parvathi Nair
- Department of Marine Science, University of Texas at Austin, 750 Channel View Drive, Port Aransas, TX 78373, USA
| | - Cambria M Miller
- Department of Marine Science, University of Texas at Austin, 750 Channel View Drive, Port Aransas, TX 78373, USA
| | - Lee A Fuiman
- Department of Marine Science, University of Texas at Austin, 750 Channel View Drive, Port Aransas, TX 78373, USA
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Hasegawa K, Yano Y, Honda K, Ogura Y. DHA and EPA levels in a piscivorous fish changed by preying upon stocked salmon fry. Sci Rep 2023; 13:15278. [PMID: 37714890 PMCID: PMC10504290 DOI: 10.1038/s41598-023-42530-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 09/11/2023] [Indexed: 09/17/2023] Open
Abstract
Increases in prey population size can affect the physiology and ecology of upper-trophic level organisms. This phenomenon is known as a bottom-up effect. For example, the increased abundance of prey resources can trigger physiological (internal) changes in predators, such as improvements in nutritional status. However, these physiological aspects of bottom-up effects have not been considered. In this study, we tested the hypothesis that white-spotted charr Salvelinus leucomaenis, a salmonid fish, increases body stores of omega-3 fatty acids, especially docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), by preying upon stocked hatchery-reared masu salmon Oncorhynchus masou fry in streams. The dynamics of fatty acid contents in charr inhabiting salmon-stocked and unstocked streams clearly support this hypothesis: fatty acid contents (DHA, EPA, and total fatty acid) increased after stocking in stocked streams, but not in unstocked streams. In addition, DHA increased with increasing body size of white-spotted charr and vice versa for EPA. The impacts of human activities, such as fish stocking, on freshwater ecosystems are a matter of serious concern for conservation. Future attempts to gain a comprehensive understanding of the impacts of fish stocking should consider not only community ecology but also physiology.
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Affiliation(s)
- Koh Hasegawa
- Fisheries Resources Institute, Japan Fisheries Research and Education Agency, Sapporo, Hokkaido, 062-0922, Japan.
| | - Yutaka Yano
- Fisheries Resources Institute, Japan Fisheries Research and Education Agency, Sapporo, Hokkaido, 062-0922, Japan
| | - Kentaro Honda
- Fisheries Resources Institute, Japan Fisheries Research and Education Agency, Sapporo, Hokkaido, 062-0922, Japan
| | - Yuhei Ogura
- Fisheries Resources Institute, Japan Fisheries Research and Education Agency, Sapporo, Hokkaido, 062-0922, Japan
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7
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Sánchez-Hernández J. Fresh perspectives on the River Continuum Concept require trophic ecology approaches focussed on food web structure and energy mobilisation routes. J Anim Ecol 2023; 92:957-964. [PMID: 37132260 DOI: 10.1111/1365-2656.13928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 03/28/2023] [Indexed: 05/04/2023]
Abstract
Stream-dwelling communities are expected to show a gradual replacement of the dominant feeding types following the type of resources found along the river continuum. Yet, the underlying longitudinal gradients in food web structure and energy flow-paths remain poorly understood. Here, I synthesise novel research on the River Continuum Concept (RCC) and identify promising areas for future research linked to longitudinal changes in food-chain length and energy mobilisation routes. For example, feeding links and connectance should reach maximum values in mid-order rivers and then decrease to river mouths following uncovered longitudinal diversity patterns. Regarding energy mobilisation routes, a gradual replacement in the food web fuelling between allochthonous (leaf litter) and autochthonous (periphyton) resources should be expected. Beyond longitudinal changes in primary basal resource to consumer paths, other allochthonous (e.g. riparian arthropod inputs) and autochthonous (e.g. fish prey) inputs subsidising higher level consumers may show longitudinal changes, that is, terrestrial invertebrates decreasing but piscivory increasing downstream. However, the role of these inputs, that can alter predator niche variation and have indirect community-based effects, on both food web structure and energy flow-paths along the river continuum is not clear yet. Incorporating energy mobilisation and food web structure into RCC principles is necessary for a broad understanding of ecosystem functioning and trophic diversity in riverine systems, driving the emergence of novel insights. How function and structure of riverine food webs adapt to longitudinal changes in physical and biological environments represent a challenge for next generation of stream ecologists.
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Affiliation(s)
- Javier Sánchez-Hernández
- Departamento de Biología y Geología, Física y Química Inorgánica, Universidad Rey Juan Carlos, Móstoles, Madrid, Spain
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8
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Kowarik C, Martin-Creuzburg D, Mathers KL, Weber C, Robinson CT. Stream degradation affects aquatic resource subsidies to riparian ground-dwelling spiders. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 855:158658. [PMID: 36113799 DOI: 10.1016/j.scitotenv.2022.158658] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 06/13/2022] [Accepted: 09/06/2022] [Indexed: 06/15/2023]
Abstract
Freshwater systems have undergone drastic alterations during the last century, potentially affecting cross-boundary resource transfers between aquatic and terrestrial ecosystems. One important connection is the export of biomass by emergent aquatic insects containing omega-3 polyunsaturated fatty acids (PUFAs), especially eicosapentaenoic acid (EPA), that is scarce in terrestrial systems. Because of taxon-specific differences in PUFA content and functional traits, the contribution of different insect groups should be considered, in addition to total biomass export. In this context, one important trait is the emergence mode. Stoneflies, in contrast to other aquatic insects, crawl to land to emerge instead of flying directly from the water surface, making them accessible to ground-dwelling predators. Because stoneflies are especially susceptible to environmental change, stream degradation might cause a mismatch of available and required nutrients, particularly for ground-dwelling predators. In this study, we estimated emergent biomass and EPA export along two streams with different levels of habitat degradation. The EPA content in aquatic insects did not differ with different degrees of habitat degradation and total biomass export in spring was with 7.9 ± 9.6 mg m-2 day-1 in the degraded and 7.3 ± 8.5 mg m-2 day-1 in the natural system, also unaffected. However, habitat degradation substantially altered the contribution of crawling emergence to the total export in spring, with no biomass export by stoneflies at the most degraded sites. The EPA content in ground-dwelling spiders was correlated with emergent stonefly biomass, making up only 16.0 ± 6.2 % of total fatty acids at sites with no stonefly emergence, but 27.3 ± 3.0 % at sites with highest stonefly emergence. Because immune function in ground-dwelling spiders has been connected to EPA levels, reduced crawling emergence might impact spider fitness. Functional traits, like emergence mode as well as nutritional quality, should be considered when assessing the effects of stream degradation on adjacent terrestrial ecosystems.
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Affiliation(s)
- Carmen Kowarik
- Eawag (Swiss Federal Institute of Aquatic Science and Technology), Department of Aquatic Ecology, 8600 Dübendorf, Switzerland; Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland.
| | | | - Kate L Mathers
- Geography and Environment, Centre for Hydrological and Ecosystem Science, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK; Eawag (Swiss Federal Institute of Aquatic Science and Technology), Department of Surface Waters Research and Management, 6047 Kastanienbaum, Switzerland
| | - Christine Weber
- Eawag (Swiss Federal Institute of Aquatic Science and Technology), Department of Surface Waters Research and Management, 6047 Kastanienbaum, Switzerland
| | - Christopher T Robinson
- Eawag (Swiss Federal Institute of Aquatic Science and Technology), Department of Aquatic Ecology, 8600 Dübendorf, Switzerland; Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland
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9
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Závorka L, Blanco A, Chaguaceda F, Cucherousset J, Killen SS, Liénart C, Mathieu-Resuge M, Němec P, Pilecky M, Scharnweber K, Twining CW, Kainz MJ. The role of vital dietary biomolecules in eco-evo-devo dynamics. Trends Ecol Evol 2023; 38:72-84. [PMID: 36182405 DOI: 10.1016/j.tree.2022.08.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/30/2022] [Accepted: 08/31/2022] [Indexed: 12/30/2022]
Abstract
The physiological dependence of animals on dietary intake of vitamins, amino acids, and fatty acids is ubiquitous. Sharp differences in the availability of these vital dietary biomolecules among different resources mean that consumers must adopt a range of strategies to meet their physiological needs. We review the emerging work on omega-3 long-chain polyunsaturated fatty acids, focusing predominantly on predator-prey interactions, to illustrate that trade-off between capacities to consume resources rich in vital biomolecules and internal synthesis capacity drives differences in phenotype and fitness of consumers. This can then feedback to impact ecosystem functioning. We outline how focus on vital dietary biomolecules in eco-eco-devo dynamics can improve our understanding of anthropogenic changes across multiple levels of biological organization.
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Affiliation(s)
- Libor Závorka
- WasserCluster Lunz - Biologische Station, Inter-university Centre for Aquatic Ecosystem Research, A-3293 Lunz am See, Austria.
| | - Andreu Blanco
- Centro de Investigación Mariña, Universidade de Vigo, EcoCost, Campus de Vigo, As Lagoas, Marcosende, 36310, Vigo, Spain
| | - Fernando Chaguaceda
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Box 7050, 750 07 Uppsala, Sweden
| | - Julien Cucherousset
- Laboratoire Evolution et Diversité Biologique (UMR 5174 EDB), CNRS, Université Paul Sabatier - Toulouse III, 31062 Toulouse, France
| | - Shaun S Killen
- School of Biodiversity, One Health & Veterinary Medicine, Graham Kerr Building, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Camilla Liénart
- Tvärminne Zoological Station, University of Helsinki, J.A. Palménin tie 260, Hanko, 10900, Finland
| | - Margaux Mathieu-Resuge
- WasserCluster Lunz - Biologische Station, Inter-university Centre for Aquatic Ecosystem Research, A-3293 Lunz am See, Austria; Université de Brest, CNRS, IRD, Ifremer, LEMAR, 29280 Plouzané, Brittany, France; UMR DECOD (Ecosystem Dynamics and Sustainability), Ifremer, INRAE, Institut Agro, Plouzané, France
| | - Pavel Němec
- Department of Zoology, Faculty of Science, Charles University, CZ-12844 Prague, Czech Republic
| | - Matthias Pilecky
- WasserCluster Lunz - Biologische Station, Inter-university Centre for Aquatic Ecosystem Research, A-3293 Lunz am See, Austria; Danube University Krems, Dr. Karl Dorrek Straße 30, A-3500 Krems, Austria
| | - Kristin Scharnweber
- University of Potsdam, Plant Ecology and Nature Conservation, Am Mühlenberg 3, 14476 Potsdam, Germany
| | - Cornelia W Twining
- Department of Fish Ecology and Evolution, Eawag - Swiss Federal Institute of Aquatic Science and Technology, Seestrasse 79, CH-6047 Kastanienbaum, Switzerland
| | - Martin J Kainz
- WasserCluster Lunz - Biologische Station, Inter-university Centre for Aquatic Ecosystem Research, A-3293 Lunz am See, Austria; Danube University Krems, Dr. Karl Dorrek Straße 30, A-3500 Krems, Austria
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10
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Závorka L, Wallerius ML, Kainz MJ, Höjesjö J. Linking omega-3 polyunsaturated fatty acids in natural diet with brain size of wild consumers. Oecologia 2022; 199:797-807. [PMID: 35960390 DOI: 10.1007/s00442-022-05229-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 07/20/2022] [Indexed: 01/27/2023]
Abstract
Omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) are key structural lipids and their dietary intake is essential for brain development of virtually all vertebrates. The importance of n-3 LC-PUFA has been demonstrated in clinical and laboratory studies, but little is known about how differences in the availability of n-3 LC-PUFA in natural prey influence brain development of wild consumers. Consumers foraging at the interface of aquatic and terrestrial food webs can differ substantially in their intake of n-3 LC-PUFA, which may lead to differences in brain development, yet this hypothesis remains to be tested. Here we use the previously demonstrated shift towards higher reliance on n-3 LC-PUFA deprived terrestrial prey of native brown trout Salmo trutta living in sympatry with invasive brook trout Salvelinus fontinalis to explore this hypothesis. We found that the content of n-3 LC-PUFA in muscle tissues of brown trout decreased with increasing consumption of n-3 LC-PUFA deprived terrestrial prey. Brain volume was positively related to the content of the n-3 LC-PUFA, docosahexaenoic acid, in muscle tissues of brown trout. Our study thus suggests that increased reliance on diets low in n-3 LC-PUFA, such as terrestrial subsidies, can have a significant negative impact on brain development of wild trout. Our findings provide the first evidence of how brains of wild vertebrate consumers response to scarcity of n-3 LC-PUFA content in natural prey.
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Affiliation(s)
- Libor Závorka
- WasserCluster Lunz, Inter-university Centre for Aquatic Ecosystem Research, 3293, Lunz am See, Austria.
| | - Magnus Lovén Wallerius
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 463, 405 30, Gothenburg, Sweden
| | - Martin J Kainz
- WasserCluster Lunz, Inter-university Centre for Aquatic Ecosystem Research, 3293, Lunz am See, Austria.,Department of Biomedical Research, Danube University Krems, 3500, Krems, Austria
| | - Johan Höjesjö
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 463, 405 30, Gothenburg, Sweden
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11
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Pilecky M, Závorka L, Soto DX, Guo F, Wassenaar LI, Kainz MJ. Assessment of Compound-Specific Fatty Acid δ 13C and δ 2H Values to Track Fish Mobility in a Small Sub-alpine Catchment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:11051-11060. [PMID: 35861449 PMCID: PMC9352314 DOI: 10.1021/acs.est.2c02089] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 06/28/2022] [Accepted: 07/06/2022] [Indexed: 06/15/2023]
Abstract
Methods for identifying origin, movement, and foraging areas of animals are essential for understanding ecosystem connectivity, nutrient flows, and other ecological processes. Telemetric methods can provide detailed spatial coverage but are limited to a minimum body size of specimen for tagging. In recent years, stable isotopes have been increasingly used to track animal migration by linking landscape isotope patterns into movement (isoscapes). However, compared to telemetric methods, the spatial resolution of bulk stable isotopes is low. Here, we examined a novel approach by evaluating the use of compound-specific hydrogen and carbon stable isotopes of fatty acids (δ2HFA and δ13CFA) from fish liver, muscle, brain, and eye tissues for identifying site specificity in a 254 km2 sub-alpine river catchment. We analyzed 208 fish (European bullhead, rainbow trout, and brown trout) collected in 2016 and 2018 at 15 different sites. δ13CFA values of these fish tissues correlated more among each other than those of δ2HFA values. Both δ2HFA and δ13CFA values showed tissue-dependent isotopic fractionation, while fish taxa had only small effects. The highest site specificity was for δ13CDHA values, while the δ2H isotopic difference between linoleic acid and alpha-linolenic acid resulted in the highest site specificity. Using linear discrimination analysis of FA isotope values, over 90% of fish could be assigned to their location of origin; however, the accuracy dropped to about 56% when isotope data from 2016 were used to predict the sites for samples collected in 2018, suggesting temporal shifts in site specificity of δ2HFA and δ13CFA. However, the predictive power of δ2HFA and δ13CFA over this time interval was still higher than site specificity of bulk tissue isotopes for a single time point. In summary, compound-specific isotope analysis of fatty acids may become a highly effective tool for assessing fine and large-scale movement and foraging areas of animals.
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Affiliation(s)
- Matthias Pilecky
- WasserCluster
Lunz—Biologische Station, Inter-University
Center for Aquatic Ecosystem Research, Dr. Carl-Kupelwieser Promenade 5, 3293 Lunz am See, Austria
- Donau-Universität
Krems, Department for Biomedical Research, Dr. Karl-Dorrek-Straße 30, 3500 Krems, Austria
| | - Libor Závorka
- WasserCluster
Lunz—Biologische Station, Inter-University
Center for Aquatic Ecosystem Research, Dr. Carl-Kupelwieser Promenade 5, 3293 Lunz am See, Austria
| | - David X. Soto
- International
Atomic Energy Agency, Isotope Hydrology Section, Vienna International Centre, A-1400 Vienna, Austria
| | - Fen Guo
- Guangdong
Provincial Key Laboratory of Water Quality Improvement and Ecological
Restoration for Watersheds, Institute of Environmental and Ecological
Engineering, Guangdong University of Technology, Guangzhou 511458, China
| | - Leonard I. Wassenaar
- WasserCluster
Lunz—Biologische Station, Inter-University
Center for Aquatic Ecosystem Research, Dr. Carl-Kupelwieser Promenade 5, 3293 Lunz am See, Austria
- Donau-Universität
Krems, Department for Biomedical Research, Dr. Karl-Dorrek-Straße 30, 3500 Krems, Austria
- University
of Saskatchewan, Department of Geological Science, 114 Science Place, Saskatoon SK S7N 5E2, Canada
| | - Martin J. Kainz
- WasserCluster
Lunz—Biologische Station, Inter-University
Center for Aquatic Ecosystem Research, Dr. Carl-Kupelwieser Promenade 5, 3293 Lunz am See, Austria
- Donau-Universität
Krems, Department for Biomedical Research, Dr. Karl-Dorrek-Straße 30, 3500 Krems, Austria
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12
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Guo F, Ebm N, Fry B, Bunn SE, Brett MT, Ouyang X, Hager H, Kainz MJ. Basal resources of river food webs largely affect the fatty acid composition of freshwater fish. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 812:152450. [PMID: 34942260 DOI: 10.1016/j.scitotenv.2021.152450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 12/11/2021] [Accepted: 12/12/2021] [Indexed: 06/14/2023]
Affiliation(s)
- Fen Guo
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China; WasserCluster Lunz - Biologische Station, Lunz am See, Austria.
| | - Nadine Ebm
- WasserCluster Lunz - Biologische Station, Lunz am See, Austria; Functional and Evolutionary Ecology, Faculty of Life Sciences, University of Vienna, A-1030 Wien, Austria
| | - Brian Fry
- Australian Rivers Institute, Griffith University, Nathan, Qld, Australia
| | - Stuart E Bunn
- Australian Rivers Institute, Griffith University, Nathan, Qld, Australia
| | - Michael T Brett
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
| | - Xiaoguang Ouyang
- Simon F.S. Li Marine Science Laboratory, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Hannes Hager
- WasserCluster Lunz - Biologische Station, Lunz am See, Austria
| | - Martin J Kainz
- WasserCluster Lunz - Biologische Station, Lunz am See, Austria
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13
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Závorka L, Koene JP, Armstrong TA, Fehlinger L, Adams CE. Differences in brain morphology of brown trout across stream, lake, and hatchery environments. Ecol Evol 2022; 12:e8684. [PMID: 35309753 PMCID: PMC8902666 DOI: 10.1002/ece3.8684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 02/07/2022] [Accepted: 02/09/2022] [Indexed: 11/11/2022] Open
Abstract
It has been suggested that a trade‐off between cognitive capacity and developmental costs may drive brain size and morphology across fish species, but this pattern is less well explored at the intraspecific level. Physical habitat complexity has been proposed as a key selection pressure on cognitive capacity that shapes brain morphology of fishes. In this study, we compared brain morphology of brown trout, Salmo trutta, from stream, lake, and hatchery environments, which generally differ in physical complexity ranging from low habitat complexity in the hatchery to high habitat complexity in streams and intermediate complexity in lakes. We found that brain size, and the size of optic tectum and telencephalon differed across the three habitats, both being largest in lake fish with a tendency to be smaller in the stream compared to hatchery fish. Therefore, our findings do not support the hypothesis that in brown trout the volume of brain and its regions important for navigation and decision‐making increases in physically complex habitats. We suggest that the observed differences in brain size might be associated with diet quality and habitat‐specific behavioral adaptations rather than physical habitat complexity.
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Affiliation(s)
- Libor Závorka
- WasserCluster Lunz - Inter-University Centre for Aquatic Ecosystem Research Lunz am See Austria.,Institute of Biodiversity, Animal Health and Comparative Medicine College of Medical, Veterinary and Life Sciences University of Glasgow Glasgow UK
| | - J Peter Koene
- Institute of Biodiversity, Animal Health and Comparative Medicine College of Medical, Veterinary and Life Sciences University of Glasgow Glasgow UK.,Scottish Centre for Ecology and the Natural Environment (SCENE) University of Glasgow Glasgow UK
| | - Tiffany A Armstrong
- Institute of Biodiversity, Animal Health and Comparative Medicine College of Medical, Veterinary and Life Sciences University of Glasgow Glasgow UK
| | - Lena Fehlinger
- WasserCluster Lunz - Inter-University Centre for Aquatic Ecosystem Research Lunz am See Austria
| | - Colin E Adams
- Scottish Centre for Ecology and the Natural Environment (SCENE) University of Glasgow Glasgow UK
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