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Allen DC, Larson J, Murphy CA, Garcia EA, Anderson KE, Busch MH, Argerich A, Belskis AM, Higgins KT, Penaluna BE, Saenz V, Jones J, Whiles MR. Global patterns of allochthony in stream-riparian meta-ecosystems. Ecol Lett 2024; 27:e14401. [PMID: 38468439 DOI: 10.1111/ele.14401] [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: 08/28/2023] [Revised: 02/18/2024] [Accepted: 02/19/2024] [Indexed: 03/13/2024]
Abstract
Ecosystems that are coupled by reciprocal flows of energy and nutrient subsidies can be viewed as a single "meta-ecosystem." Despite these connections, the reciprocal flow of subsidies is greatly asymmetrical and seasonally pulsed. Here, we synthesize existing literature on stream-riparian meta-ecosystems to quantify global patterns of the amount of subsidy consumption by organisms, known as "allochthony." These resource flows are important since they can comprise a large portion of consumer diets, but can be disrupted by human modification of streams and riparian zones. Despite asymmetrical subsidy flows, we found stream and riparian consumer allochthony to be equivalent. Although both fish and stream invertebrates rely on seasonally pulsed allochthonous resources, we find allochthony varies seasonally only for fish, being nearly three times greater during the summer and fall than during the winter and spring. We also find that consumer allochthony varies with feeding traits for aquatic invertebrates, fish, and terrestrial arthropods, but not for terrestrial vertebrates. Finally, we find that allochthony varies by climate for aquatic invertebrates, being nearly twice as great in arid climates than in tropical climates, but not for fish. These findings are critical to understanding the consequences of global change, as ecosystem connections are being increasingly disrupted.
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Affiliation(s)
- Daniel C Allen
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - James Larson
- U.S. Geological Survey, Upper Midwest Environmental Sciences Center, La Crosse, Wisconsin, USA
| | - Christina A Murphy
- U.S. Geological Survey, Maine Cooperative Fish and Wildlife Research Unit, Orono, Maine, USA
| | - Erica A Garcia
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northwest Territories, Australia
| | - Kurt E Anderson
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, California, USA
| | - Michelle H Busch
- Kansas Biological Survey, University of Kansas, Lawrence, Kansas, USA
| | - Alba Argerich
- School of Natural Resources, University of Missouri, Columbia, Missouri, USA
| | - Alice M Belskis
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Kierstyn T Higgins
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, Pennsylvania, USA
| | | | - Veronica Saenz
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Jay Jones
- Institute of Arctic Biology and Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - Matt R Whiles
- Soil, Water, and Ecosystems Sciences Department, University of Florida, Gainesville, Florida, USA
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2
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Bipa NJ, Stradiotti G, Righetti M, Pisaturo GR. Impacts of hydropeaking: A systematic review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169251. [PMID: 38101637 DOI: 10.1016/j.scitotenv.2023.169251] [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: 09/07/2023] [Revised: 11/30/2023] [Accepted: 12/07/2023] [Indexed: 12/17/2023]
Abstract
Hydropower is commonly considered a renewable energy source. Nevertheless, this does not imply an absence of impacts on the riverine ecosystem, the extent of which is expected to increase in the coming years due to the energy transition from fossil fuels to renewable sources and for the climate change. A common consequence of hydroelectric power generation is hydropeaking, which causes rapid and frequent fluctuations in the water flow downstream of hydropower plants. The review incorporates 155 relevant studies published up until November 2023 and follows a systematic review method, Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), which is a multi-stage systematic procedure for the identification and selection of research documents. The selected studies highlighted several prominent impacts of hydropeaking on aquatic environments. The primary effects include alterations in flow patterns, modification of water temperature, changes in sediment dynamics and fluctuations in dissolved gas levels. These alterations have been found to affect various aspects of aquatic ecosystems, including fish growth, behavior, reproductive success, habitat, and migration patterns, and benthic macroinvertebrate communities. Furthermore, hydropeaking can also lead to habitat fragmentation, erosion, and loss of riparian vegetation, thereby impacting terrestrial ecosystems that depend on the aquatic environment. Despite the body of literature reviewed, several knowledge gaps were identified, underscoring the need for further research. There is limited understanding of the long-term ecological consequences of hydropeaking and its cumulative effects on aquatic ecosystems. Additionally, there is lack of consensus regarding the quantification of ecosystem services, economic impact, soil moisture content, and weighted usable area due to flow fluctuation and global evolution of energy production from renewable energy sources. Addressing the identified research gaps is crucial for achieving a balance between energy production and the conservation of freshwater ecosystems in the context of a rapidly changing global climate.
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Affiliation(s)
- Nusrat Jahan Bipa
- Sustainable Development and Climate Change, University School for Advanced Studies IUSS, Pavia, Italy; Free University of Bozen-Bolzano, Faculty of Engineering, Universitätsplatz 5, 39100 Bolzano, Italy.
| | - Giulia Stradiotti
- Free University of Bozen-Bolzano, Faculty of Engineering, Universitätsplatz 5, 39100 Bolzano, Italy.
| | - Maurizio Righetti
- Free University of Bozen-Bolzano, Faculty of Engineering, Universitätsplatz 5, 39100 Bolzano, Italy.
| | - Giuseppe Roberto Pisaturo
- Free University of Bozen-Bolzano, Faculty of Engineering, Universitätsplatz 5, 39100 Bolzano, Italy.
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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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4
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O'Brien L, Siboni N, Seymour JR, Balzer M, Mitrovic S. Tributary Inflows to a Regulated River Influence Bacterial Communities and Increase Bacterial Carbon Assimilation. MICROBIAL ECOLOGY 2023; 86:2642-2654. [PMID: 37480518 PMCID: PMC10640455 DOI: 10.1007/s00248-023-02271-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/14/2023] [Indexed: 07/24/2023]
Abstract
Inflows from unregulated tributaries change the physical, chemical, and biotic conditions in receiving regulated rivers, impacting microbial community structure and metabolic function. Understanding how tributary inflows affect bacterial carbon production (BCP) is integral to understanding energy transfer in riverine ecosystems. To investigate the role of tributary inflows on bacterial community composition and BCP, a ~90th percentile natural flow event was sampled over 5 days along the Lachlan River and its tributaries within the Murray-Darling Basin of eastern Australia. Increased tributary inflows after rainfall corresponded with a significantly different and more diverse bacterial community in the regulated mainstem. The major contributor to this difference was an increase in relative abundance of bacterial groups with a potential metabolic preference for humic substances (Burkholderiaceae Polynucleobacter, Alcaligenaceae GKS98 freshwater group, Saccharimonadia) and a significant decrease in Spirosomaceae Pseudarcicella, known to metabolise algal exudates. Increases in orthophosphate and river discharge explained 31% of community change, suggesting a combination of resource delivery and microbial community coalescence as major drivers. BCP initially decreased significantly with tributary inflows, but the total load of carbon assimilated by bacteria increased by up to 20 times with flow due to increased water volume. The significant drivers of BCP were dissolved organic carbon, water temperature, and conductivity. Notably, BCP was not correlated with bacterial diversity or community composition. Tributary inflows were shown to alter mainstem bacterial community structure and metabolic function to take advantage of fresh terrestrial dissolved organic material, resulting in substantial changes to riverine carbon assimilation over small times scales.
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Affiliation(s)
- Lauren O'Brien
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW, Australia.
| | - Nachshon Siboni
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Justin R Seymour
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Matthew Balzer
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW, Australia
| | - Simon Mitrovic
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW, Australia
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5
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Acharya S, Holland A, Rees G, Brooks A, Coleman D, Hepplewhite C, Mika S, Bond N, Silvester E. Relevance of tributary inflows for driving molecular composition of dissolved organic matter (DOM) in a regulated river system. WATER RESEARCH 2023; 237:119975. [PMID: 37104936 DOI: 10.1016/j.watres.2023.119975] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 03/20/2023] [Accepted: 04/11/2023] [Indexed: 05/09/2023]
Abstract
River regulation by dams can alter flow regimes and organic matter dynamics, but less is known about how unregulated tributaries regulate organic matter composition and processing in the regulated river below the confluence. This study reports on water chemistry, especially dissolved organic matter (DOM) concentration and composition (dissolved organic carbon (DOC), organic nitrogen (DON), organic phosphorus (DOP) and combined amino acids (DCAA)) along the regulated Tumut and unregulated Goobarragandra (tributary) rivers under different flow conditions (base flow vs storm event) in south-east Australia. The tributary was significantly different from regulated and downstream sites during base flow conditions with higher temperature, pH, buffering capacity, DOC and nutrient concentrations (DON, DOP, DCAA). DOM characterisation by spectrometry and size exclusion chromatography revealed that the tributary contained a higher proportion of terrestrially derived humic-like and fulvic-like DOM. In contrast, regulated and downstream sites contained higher proportion of microbially derived DOM such as low molecular weight neutrals and protein-like components. Storm pulses of tributary flows into the regulated system, influenced both concentration and composition of DOM at the downstream site, which more strongly resembled the tributary site than the regulated site during the storm event. Additionally, we found that the tributary supplied fresh DOM, including small organic molecules to the regulated system during storm events. The presence of these different types of labile DOM can increase primary productivity and ecological functioning within regulated river reaches downstream of tributary junctions. This has important implications for the protection of unregulated tributary inflows within regulated river basins.
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Affiliation(s)
- Suman Acharya
- Department of Environment and Genetics, Centre for Freshwater Ecosystems, School of Agriculture, Biomedicine and Environment, La Trobe University, Albury/Wodonga Campus, 3690 Wodonga, VIC, Australia.
| | - Aleicia Holland
- Department of Environment and Genetics, Centre for Freshwater Ecosystems, School of Agriculture, Biomedicine and Environment, La Trobe University, Albury/Wodonga Campus, 3690 Wodonga, VIC, Australia
| | - Gavin Rees
- CSIRO Land and Water, Institute for Land, Water and Society, Charles Sturt University, 2640 Thurgoona, NSW, Australia
| | - Andrew Brooks
- Department of Planning and Environment, Surface Water Science, NSW, Australia
| | - Daniel Coleman
- Department of Planning and Environment, Surface Water Science, NSW, Australia
| | - Chris Hepplewhite
- Department of Planning and Environment, Surface Water Science, NSW, Australia
| | - Sarah Mika
- School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Nick Bond
- Department of Environment and Genetics, Centre for Freshwater Ecosystems, School of Agriculture, Biomedicine and Environment, La Trobe University, Albury/Wodonga Campus, 3690 Wodonga, VIC, Australia
| | - Ewen Silvester
- Department of Environment and Genetics, Centre for Freshwater Ecosystems, School of Agriculture, Biomedicine and Environment, La Trobe University, Albury/Wodonga Campus, 3690 Wodonga, VIC, Australia
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6
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Lee IO, Noh J, Kim B, Kwon I, Kim H, Kwon BO, Peng Y, Hu Z, Khim JS. Food web dynamics in the mangrove ecosystem of the Pearl River Estuary surrounded by megacities. MARINE POLLUTION BULLETIN 2023; 189:114747. [PMID: 36863274 DOI: 10.1016/j.marpolbul.2023.114747] [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: 11/16/2022] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
Global recognition that mangroves support coastal ecosystem services has increased; however, studies on trophic dynamics in mangrove ecosystems remain limited. We seasonally analysed the δ13C and δ15N of 34 consumers and 5 diets to elucidate the food web dynamics in the Pearl River Estuary (PRE). Fish had a large niche space during the monsoon summer, reflecting increased trophic roles. In contrast, the small niche space of benthos over seasons reflected consistent trophic positions. Consumers mainly utilized plant-derived organic matters in the dry season and particulate organic matters in the wet season. The present study with literature reviews revealed characteristics of the PRE food web with the depleted δ13C and enriched δ15N, indicating a high contribution of mangrove-derived organic carbon and sewage input, particularly in the wet season. Overall, this study confirmed the seasonal and spatial trophic dynamics in mangrove forests surrounding megacities for future sustainable mangrove ecosystem management.
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Affiliation(s)
- In Ok Lee
- School of Earth and Environmental Sciences & Research Institute of Oceanography, Seoul National University, Seoul 08826, Republic of Korea
| | - Junsung Noh
- Department of Environment & Energy, Sejong University, Seoul 05006, Republic of Korea.
| | - Beomgi Kim
- School of Earth and Environmental Sciences & Research Institute of Oceanography, Seoul National University, Seoul 08826, Republic of Korea
| | - Inha Kwon
- School of Earth and Environmental Sciences & Research Institute of Oceanography, Seoul National University, Seoul 08826, Republic of Korea
| | - Hosang Kim
- School of Earth and Environmental Sciences & Research Institute of Oceanography, Seoul National University, Seoul 08826, Republic of Korea
| | - Bong-Oh Kwon
- Department of Marine Biotechnology, Kunsan National University, Kunsan 54150, Republic of Korea
| | - Yisheng Peng
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 501275, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou, China
| | - Zhan Hu
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Zhuhai, 519082, China
| | - Jong Seong Khim
- School of Earth and Environmental Sciences & Research Institute of Oceanography, Seoul National University, Seoul 08826, Republic of Korea.
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7
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Healy BD, Budy P, Conner MM, Omana Smith EC. Life and death in a dynamic environment: Invasive trout, floods, and intraspecific drivers of translocated populations. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022. [PMID: 35403769 DOI: 10.6084/m9.figshare.c.5805593.v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Understanding the relative strengths of intrinsic and extrinsic factors regulating populations is a long-standing focus of ecology and critical to advancing conservation programs for imperiled species. Conservation could benefit from an increased understanding of factors influencing vital rates (somatic growth, recruitment, survival) in small, translocated populations, which is lacking owing to difficulties in long-term monitoring of rare species. Translocations, here defined as the transfer of wild-captured individuals from source populations to new habitats, are widely used for species conservation, but outcomes are often minimally monitored, and translocations that are monitored often fail. To improve our understanding of how translocated populations respond to environmental variation, we developed and tested hypotheses related to intrinsic (density dependent) and extrinsic (introduced rainbow trout Oncorhynchus mykiss, stream flow and temperature regime) causes of vital rate variation in endangered humpback chub (Gila cypha) populations translocated to Colorado River tributaries in the Grand Canyon (GC), USA. Using biannual recapture data from translocated populations over 10 years, we tested hypotheses related to seasonal somatic growth, and recruitment and population growth rates with linear mixed-effects models and temporal symmetry mark-recapture models. We combined data from recaptures and resights of dispersed fish (both physical captures and continuously recorded antenna detections) from throughout GC to test survival hypotheses, while accounting for site fidelity, using joint live-recapture/live-resight models. While recruitment only occurred in one site, which also drove population growth (relative to survival), evidence supported hypotheses related to density dependence in growth, survival, and recruitment, and somatic growth and recruitment were further limited by introduced trout. Mixed-effects models explained between 67% and 86% of the variation in somatic growth, which showed increased growth rates with greater flood-pulse frequency during monsoon season. Monthly survival was 0.56-0.99 and 0.80-0.99 in the two populations, with lower survival during periods of higher intraspecific abundance and low flood frequency. Our results suggest translocations can contribute toward the recovery of large-river fishes, but continued suppression of invasive fishes to enhance recruitment may be required to ensure population resilience. Furthermore, we demonstrate the importance of flooding to population demographics in food-depauperate, dynamic, invaded systems.
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Affiliation(s)
- Brian D Healy
- Department of Watershed Sciences and the Ecology Center, Utah State University, Logan, Utah, USA
- Native Fish Ecology and Conservation Program, Division of Science and Resource Management, Grand Canyon National Park, National Park Service, Flagstaff, Arizona, USA
| | - Phaedra Budy
- Department of Watershed Sciences and the Ecology Center, Utah State University, Logan, Utah, USA
- United States Geological Survey, Utah Cooperative Fish and Wildlife Research Unit, Department of Watershed Sciences, Utah State University, Logan, Utah, USA
| | - Mary M Conner
- Department of Wildland Resources and the Ecology Center, Utah State University, Logan, Utah, USA
| | - Emily C Omana Smith
- Native Fish Ecology and Conservation Program, Division of Science and Resource Management, Grand Canyon National Park, National Park Service, Flagstaff, Arizona, USA
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8
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Healy BD, Budy P, Conner MM, Omana Smith EC. Life and death in a dynamic environment: Invasive trout, floods, and intraspecific drivers of translocated populations. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e2635. [PMID: 35403769 PMCID: PMC9541007 DOI: 10.1002/eap.2635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 01/25/2022] [Accepted: 02/24/2022] [Indexed: 05/14/2023]
Abstract
Understanding the relative strengths of intrinsic and extrinsic factors regulating populations is a long-standing focus of ecology and critical to advancing conservation programs for imperiled species. Conservation could benefit from an increased understanding of factors influencing vital rates (somatic growth, recruitment, survival) in small, translocated populations, which is lacking owing to difficulties in long-term monitoring of rare species. Translocations, here defined as the transfer of wild-captured individuals from source populations to new habitats, are widely used for species conservation, but outcomes are often minimally monitored, and translocations that are monitored often fail. To improve our understanding of how translocated populations respond to environmental variation, we developed and tested hypotheses related to intrinsic (density dependent) and extrinsic (introduced rainbow trout Oncorhynchus mykiss, stream flow and temperature regime) causes of vital rate variation in endangered humpback chub (Gila cypha) populations translocated to Colorado River tributaries in the Grand Canyon (GC), USA. Using biannual recapture data from translocated populations over 10 years, we tested hypotheses related to seasonal somatic growth, and recruitment and population growth rates with linear mixed-effects models and temporal symmetry mark-recapture models. We combined data from recaptures and resights of dispersed fish (both physical captures and continuously recorded antenna detections) from throughout GC to test survival hypotheses, while accounting for site fidelity, using joint live-recapture/live-resight models. While recruitment only occurred in one site, which also drove population growth (relative to survival), evidence supported hypotheses related to density dependence in growth, survival, and recruitment, and somatic growth and recruitment were further limited by introduced trout. Mixed-effects models explained between 67% and 86% of the variation in somatic growth, which showed increased growth rates with greater flood-pulse frequency during monsoon season. Monthly survival was 0.56-0.99 and 0.80-0.99 in the two populations, with lower survival during periods of higher intraspecific abundance and low flood frequency. Our results suggest translocations can contribute toward the recovery of large-river fishes, but continued suppression of invasive fishes to enhance recruitment may be required to ensure population resilience. Furthermore, we demonstrate the importance of flooding to population demographics in food-depauperate, dynamic, invaded systems.
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Affiliation(s)
- Brian D. Healy
- Department of Watershed Sciences and the Ecology CenterUtah State UniversityLoganUtahUSA
- Native Fish Ecology and Conservation Program, Division of Science and Resource ManagementGrand Canyon National Park, National Park ServiceFlagstaffArizonaUSA
| | - Phaedra Budy
- Department of Watershed Sciences and the Ecology CenterUtah State UniversityLoganUtahUSA
- United States Geological Survey, Utah Cooperative Fish and Wildlife Research Unit, Department of Watershed SciencesUtah State UniversityLoganUtahUSA
| | - Mary M. Conner
- Department of Wildland Resources and the Ecology CenterUtah State UniversityLoganUtahUSA
| | - Emily C. Omana Smith
- Native Fish Ecology and Conservation Program, Division of Science and Resource ManagementGrand Canyon National Park, National Park ServiceFlagstaffArizonaUSA
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9
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Trophic niches of native and nonnative fishes along a river-reservoir continuum. Sci Rep 2021; 11:12140. [PMID: 34108584 PMCID: PMC8190098 DOI: 10.1038/s41598-021-91730-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/31/2021] [Indexed: 11/17/2022] Open
Abstract
Instream barriers can constrain dispersal of nonnative fishes, creating opportunities to test their impact on native communities above and below these barriers. Deposition of sediments in a river inflow to Lake Powell, USA resulted in creation of a large waterfall prohibiting upstream movement of fishes from the reservoir allowing us to evaluate the trophic niche of fishes above and below this barrier. We expected niche overlap among native and nonnative species would increase in local assemblages downstream of the barrier where nonnative fish diversity and abundance were higher. Fishes upstream of the barrier had more distinct isotopic niches and species exhibited a wider range in δ15N relative to downstream. In the reservoir, species were more constrained in δ15N and differed more in δ13C, representing a shorter, wider food web. Differences in energetic pathways and resource availability among habitats likely contributed to differences in isotopic niches. Endangered Razorback Sucker (Xyrauchen texanus) aggregate at some reservoir inflows in the Colorado River basin, and this is where we found the highest niche overlap among species. Whether isotopic niche overlap among adult native and nonnative species has negative consequences is unclear, because data on resource availability and use are lacking; however, these observations do indicate the potential for competition. Still, the impacts of diet overlap among trophic generalists, such as Razorback Sucker, are likely low, particularly in habitats with diverse and abundant food bases such as river-reservoir inflows.
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10
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Mejia F, Torgersen C, Berntsen E, Maroney J, Connor J, Fullerton AH, Ebersole J, Lorang M. Longitudinal, lateral, vertical and temporal thermal heterogeneity in a large impounded river: implications for cold-water refuges. REMOTE SENSING 2020; 12:1-1386. [PMID: 32850136 PMCID: PMC7443969 DOI: 10.3390/rs12091386] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Dam operations can affect mixing of the water column thereby influencing thermal heterogeneity spatially and temporally. This occurs by restricting or eliminating connectivity in longitudinal, lateral, vertical and temporal dimensions. We examined thermal heterogeneity across space and time and identified potential cold-water refuges for salmonids in a large impounded river in inland northwestern USA. To describe these patterns, we used thermal infrared (TIR) imagery, in situ thermographs, and high-resolution 3-D hydraulic mapping. We explained the median water temperature and probability of occurrence of cool-water areas using generalized additive models (GAMs) at reach and sub-catchment scales, and we evaluated potential cold-water refuge occurrence in relation to these patterns. We demonstrated that (1) lateral contributions from tributaries dominated thermal heterogeneity; (2) thermal variability at confluences was approximately an order of magnitude greater than of the main stem; (3) potential cold-water refuges were mostly found at confluences; and (4) the probability of occurrence of cool areas and median water temperature were associated with channel geomorphology and distance from dam. These findings highlight the importance of using multiple approaches to describe thermal heterogeneity in large impounded rivers and the need to incorporate these types of rivers in the understanding of thermal riverscapes because of their limited representation in the literature.
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Affiliation(s)
- F.H. Mejia
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Cascadia Field Station
| | - C.E. Torgersen
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Cascadia Field Station
| | - E.K. Berntsen
- Kalispel Tribe, Natural Resources Department, National Marine Fisheries Service, National Oceanic and Atmospheric Administration (NOAA)
| | - J.R. Maroney
- Kalispel Tribe, Natural Resources Department, National Marine Fisheries Service, National Oceanic and Atmospheric Administration (NOAA)
| | - J.M. Connor
- Kalispel Tribe, Natural Resources Department, National Marine Fisheries Service, National Oceanic and Atmospheric Administration (NOAA)
| | - A. H. Fullerton
- Fish Ecology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration (NOAA)
| | - J.L. Ebersole
- U.S. Environmental Protection Agency, Center for Public Health and Environmental Assessment, Pacific, Ecological Systems Division
| | - M.S. Lorang
- FreshwaterMap, Center for Public Health and Environmental Assessment, Pacific, Ecological Systems Division
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11
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Palmer M, Ruhi A. Linkages between flow regime, biota, and ecosystem processes: Implications for river restoration. Science 2019; 365:365/6459/eaaw2087. [DOI: 10.1126/science.aaw2087] [Citation(s) in RCA: 187] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
River ecosystems are highly biodiverse, influence global biogeochemical cycles, and provide valued services. However, humans are increasingly degrading fluvial ecosystems by altering their streamflows. Effective river restoration requires advancing our mechanistic understanding of how flow regimes affect biota and ecosystem processes. Here, we review emerging advances in hydroecology relevant to this goal. Spatiotemporal variation in flow exerts direct and indirect control on the composition, structure, and dynamics of communities at local to regional scales. Streamflows also influence ecosystem processes, such as nutrient uptake and transformation, organic matter processing, and ecosystem metabolism. We are deepening our understanding of how biological processes, not just static patterns, affect and are affected by stream ecosystem processes. However, research on this nexus of flow-biota-ecosystem processes is at an early stage. We illustrate this frontier with evidence from highly altered regulated rivers and urban streams. We also identify research challenges that should be prioritized to advance process-based river restoration.
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12
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Graham EB, Stegen JC, Huang M, Chen X, Scheibe TD. Subsurface biogeochemistry is a missing link between ecology and hydrology in dam-impacted river corridors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 657:435-445. [PMID: 30550907 DOI: 10.1016/j.scitotenv.2018.11.414] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 11/27/2018] [Accepted: 11/27/2018] [Indexed: 06/09/2023]
Abstract
Global investment in hydropower is rapidly increasing, fueled by a need to manage water availability and by incentives promoting renewable energy sources. This expansion poses unrecognized risks to the world's vulnerable freshwater ecosystems. While many hydropower impacts have been investigated, dam-induced alterations to subsurface processes influence river corridor ecosystem health in ways that remain poorly understood. We advocate for a better understanding of dam impacts on subsurface biogeochemical activity, its connection to hydrology, and follow-on trophic cascades within the broader river corridor. We delineate an integrated view of hydropower impacts in which dam-induced changes to surface water flow regimes generate changes in surface-subsurface hydrologic exchange flows (HEFs) that subsequently (1) regulate resource availability for benthic microorganisms at the base of aquatic food webs and (2) impose kinetic constraints on biogeochemical reactions and organismal growth across a range of trophic levels. These HEF-driven effects on river corridor food webs, as mediated by subsurface biogeochemistry, are a key knowledge gap in our assessment of hydropower sustainability and putatively combine with other, more well-known dam impacts to result in significant changes to river corridor health. We suggest targeted laboratory and field-based studies to link hydrobiogeochemical models used to predict heat transport, biogeochemical rates, and hydrologic flow with ecological models that incorporate biomass changes in specific categories of organisms. Doing so will enable predictions of feedbacks among hydrology, temperature, biogeochemical rates, organismal abundances, and resource transfer across trophic levels. This understanding of dam impacts on subsurface hydrobiogeochemistry and its connection to the broader aquatic food web is fundamental to enabling mechanism-based decision making for sustainable hydropower operations.
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Affiliation(s)
- Emily B Graham
- Pacific Northwest National Laboratory, Richland, WA, USA.
| | - James C Stegen
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - Maoyi Huang
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - Xingyuan Chen
- Pacific Northwest National Laboratory, Richland, WA, USA
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13
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Behn KE, Baxter CV. The trophic ecology of a desert river fish assemblage: influence of season and hydrologic variability. Ecosphere 2019. [DOI: 10.1002/ecs2.2583] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Kathrine E. Behn
- Department of Biological Sciences Idaho State University Pocatello Idaho 83209 USA
| | - Colden V. Baxter
- Department of Biological Sciences Idaho State University Pocatello Idaho 83209 USA
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14
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Ruhi A, Dong X, McDaniel CH, Batzer DP, Sabo JL. Detrimental effects of a novel flow regime on the functional trajectory of an aquatic invertebrate metacommunity. GLOBAL CHANGE BIOLOGY 2018; 24:3749-3765. [PMID: 29665147 DOI: 10.1111/gcb.14133] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 02/15/2018] [Accepted: 02/23/2018] [Indexed: 06/08/2023]
Abstract
Novel flow regimes resulting from dam operations and overallocation of freshwater resources are an emerging consequence of global change. Yet, anticipating how freshwater biodiversity will respond to surging flow regime alteration requires overcoming two challenges in environmental flow science: shifting from local to riverscape-level understanding of biodiversity dynamics, and from static to time-varying characterizations of the flow regime. Here, we used time-series methods (wavelets and multivariate autoregressive models) to quantify flow-regime alteration and to link time-varying flow regimes to the dynamics of multiple local communities potentially connected by dispersal (i.e., a metacommunity). We studied the Chattahoochee River below Buford dam (Georgia, U.S.A.), and asked how flow regime alteration by a large hydropower dam may control the long-term functional trajectory of the downstream invertebrate metacommunity. We found that seasonal variation in hydropeaking synchronized temporal fluctuations in trait abundance among the flow-altered sites. Three biological trait states describing adaptation to fast flows benefitted from flow management for hydropower, but did not compensate for declines in 16 "loser" traits. Accordingly, metacommunity-wide functional diversity responded negatively to hydropeaking intensity, and stochastic simulations showed that the risk of functional diversity collapse within the next 4 years would decrease by 17% if hydropeaking was ameliorated, or by 9% if it was applied every other season. Finally, an analysis of 97 reference and 23 dam-affected river sites across the U.S. Southeast suggested that flow variation at extraneous, human-relevant scales (12-hr, 24-hr, 1-week) is relatively common in rivers affected by hydropower dams. This study advances the notion that novel flow regimes are widespread, and simplify the functional structure of riverine communities by filtering out taxa with nonadaptive traits and by spatially synchronizing their dynamics. This is relevant in the light of ongoing and future hydrologic alteration due to climate non-stationarity and the new wave of dams planned globally.
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Affiliation(s)
- Albert Ruhi
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA, USA
- National Socio-Environmental Synthesis Center (SESYNC), University of Maryland, Annapolis, MD, USA
| | - Xiaoli Dong
- Nicholas School of the Environment, Duke University, Durham, NC, USA
| | - Courtney H McDaniel
- Department of Environmental Science and Ecology, The College at Brockport, State University of New York, Brockport, NY, USA
| | - Darold P Batzer
- Department of Entomology, University of Georgia, Athens, GA, USA
| | - John L Sabo
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
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