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Krumsick KJ, Fisher JAD. Spatial variation in food web structure in a recovering marine ecosystem. PLoS One 2022; 17:e0268440. [PMID: 35594249 PMCID: PMC9122200 DOI: 10.1371/journal.pone.0268440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 04/30/2022] [Indexed: 11/18/2022] Open
Abstract
Spatial heterogeneity in food web structure and interactions may reconcile spatial variation in population and community dynamics in large marine ecosystems. In order to assess food web contributions to the different community recovery dynamics along the Newfoundland and Labrador shelf ecosystem, we quantified species interactions using stable isotope mixing models and food web metrics within three sub-regions. Representative samples of each species caught in trawls and plankton tows were analyzed for stomach contents and stable isotope ratios (δ15N and δ13C) to parameterize isotope mixing models. Regional variation, highlighted by the diets of three economically important species, was observed such that the southern region demonstrated a variety of trophic pathways of nutrient flow into the higher food web while the diets of fish in the northern regions were typically dominated by one or two pathways via dominant prey species, specifically shrimp (Pandalus sp.) and hyperiids. Food web metrics indicated that the low-diversity northern regions had higher connectance and shorter food chain lengths. This observed regional variation contributes to our understanding of the role of specific forage species to the ecosystem which is an essential contribution towards ecosystem-based management decisions.
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Affiliation(s)
- Kyle J. Krumsick
- Centre for Fisheries Ecosystems Research, Fisheries and Marine Institute of Memorial University of Newfoundland, St. John’s, Newfoundland, Canada
- * E-mail:
| | - Jonathan A. D. Fisher
- Centre for Fisheries Ecosystems Research, Fisheries and Marine Institute of Memorial University of Newfoundland, St. John’s, Newfoundland, Canada
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A spatial regime shift from predator to prey dominance in a large coastal ecosystem. Commun Biol 2020; 3:459. [PMID: 32855431 PMCID: PMC7452892 DOI: 10.1038/s42003-020-01180-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 07/23/2020] [Indexed: 11/24/2022] Open
Abstract
Regime shifts in ecosystem structure and processes are typically studied from a temporal perspective. Yet, theory predicts that in large ecosystems with environmental gradients, shifts should start locally and gradually spread through space. Here we empirically document a spatially propagating shift in the trophic structure of a large aquatic ecosystem, from dominance of large predatory fish (perch, pike) to the small prey fish, the three-spined stickleback. Fish surveys in 486 shallow bays along the 1200 km western Baltic Sea coast during 1979–2017 show that the shift started in wave-exposed archipelago areas near the open sea, but gradually spread towards the wave-sheltered mainland coast. Ecosystem surveys in 32 bays in 2014 show that stickleback predation on juvenile predators (predator–prey reversal) generates a feedback mechanism that appears to reinforce the shift. In summary, managers must account for spatial heterogeneity and dispersal to better predict, detect and confront regime shifts within large ecosystems. Eklöf et al. report a spatially propagating shift in the trophic structure along the western Baltic Sea coast. The authors use fish surveys from 1979–2017 to show a shift from dominance of large predatory fish to the small prey fish, the three-spined stickleback, starting in wave-exposed areas and gradually moving to the wave-sheltered coast.
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Kröncke I, Neumann H, Dippner JW, Holbrook S, Lamy T, Miller R, Padedda BM, Pulina S, Reed DC, Reinikainen M, Satta CT, Sechi N, Soltwedel T, Suikkanen S, Lugliè A. Comparison of biological and ecological long-term trends related to northern hemisphere climate in different marine ecosystems. NATURE CONSERVATION 2019. [DOI: 10.3897/natureconservation.34.30209] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Data from five sites of the International Long Term Ecological Research (ILTER) network in the North-Eastern Pacific, Western Arctic Ocean, Northern Baltic Sea, South-Eastern North Sea and in the Western Mediterranean Sea were analyzed by dynamic factor analysis (DFA) to trace common multi-year trends in abundance and composition of phytoplankton, benthic fauna and temperate reef fish. Multiannual trends were related to climate and environmental variables to study interactions. Two common trends in biological responses were detected, with temperature and climate indices as explanatory variables in four of the five LTER sites considered. Only one trend was observed at the fifth site, the Northern Baltic Sea, where no explanatory variables were identified. Our findings revealed quasi-synchronous biological shifts in the different marine ecosystems coincident with the 2000 climatic regime shift and provided evidence on a possible further biological shift around 2010. The observed biological modifications were coupled with abrupt or continuous increase in sea water and air temperature confirming the key-role of temperature in structuring marine communities.
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Triki Z, Bshary R. Fluctuations in coral reef fish densities after environmental disturbances on the northern Great Barrier Reef. PeerJ 2019; 7:e6720. [PMID: 30993047 PMCID: PMC6459176 DOI: 10.7717/peerj.6720] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 03/04/2019] [Indexed: 11/20/2022] Open
Abstract
Global warming is predicted to increase the frequency and or severity of many disturbances including cyclones, storms, and prolonged heatwaves. The coral reef at Lizard Island, part of the Great Barrier Reef, has been recently exposed to a sequence of severe tropical cyclones (i.e., Ita in 2014 and Nathan in 2015) and a coral bleaching in the year 2016. Reef fishes are an essential part of the coral reef ecosystem, and their abundance is thus a good marker to estimate the magnitude of such disturbances. Here, we examined whether the recent disturbances at Lizard Island had an impact on the coral reef fish communities. To do this, we examined fish survey data collected before and after the disturbances for potential changes in total fish density post-disturbance. Also, by sorting fish species into 11 functional groups based on their trophic level (i.e., diet), we further explored the density changes within each functional group. Our findings showed an overall decline of 68% in fish density post-disturbance, with a significant density decrease in nine of 11 trophic groups. These nine groups were: browsers, corallivores, detritivores, excavator/scrapers, grazers, macro-invertivores, pisci-invertivores, planktivores, and spongivores. The piscivores, on the other hand, were the only "winners," wherein their density showed an increase post-disturbance. These changes within functional groups might have a further impact on the trophodynamics of the food web. In summary, our findings provide evidence that the fish assemblage on the reefs around Lizard Island was considerably affected by extreme weather events, leading to changes in the functional composition of the reef fish assemblage.
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Affiliation(s)
- Zegni Triki
- Institute of Biology, University of Neuchâtel, Neuchâtel, NE, Switzerland
| | - Redouan Bshary
- Institute of Biology, University of Neuchâtel, Neuchâtel, NE, Switzerland
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Möllmann C, Folke C, Edwards M, Conversi A. Marine regime shifts around the globe: theory, drivers and impacts. Philos Trans R Soc Lond B Biol Sci 2015; 370:20130260. [PMCID: PMC4247398 DOI: 10.1098/rstb.2013.0260] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023] Open
Affiliation(s)
- Christian Möllmann
- Institute for Hydrobiology and Fisheries Science, University of Hamburg, Grosse Elbstrasse 133, 22767 Hamburg, Germany
| | - Carl Folke
- Beijer Institute, Royal Swedish Academy of Sciences, PO Box 50005, 104 05 Stockholm, Sweden
- Stockholm Resilience Centre, Stockholm University, Kräftriket 2B, 106 91 Stockholm, Sweden
| | - Martin Edwards
- SAHFOS, The Laboratory, Citadel Hill, The Hoe, Plymouth PL1 2PB, UK
| | - Alessandra Conversi
- SAHFOS, The Laboratory, Citadel Hill, The Hoe, Plymouth PL1 2PB, UK
- Institute of Marine Sciences ISMAR, National Research Council of Italy CNR, Forte Santa Teresa, Loc Pozzuolo, Lerici, 19032 La Spezia, Italy
- Centre for Marine and Coastal Policy Research, Marine Institute, Plymouth University, Plymouth PL4 8AA, UK
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Gårdmark A, Casini M, Huss M, van Leeuwen A, Hjelm J, Persson L, de Roos AM. Regime shifts in exploited marine food webs: detecting mechanisms underlying alternative stable states using size-structured community dynamics theory. Philos Trans R Soc Lond B Biol Sci 2015; 370:20130262. [PMCID: PMC4247399 DOI: 10.1098/rstb.2013.0262] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023] Open
Abstract
Many marine ecosystems have undergone ‘regime shifts’, i.e. abrupt reorganizations across trophic levels. Establishing whether these constitute shifts between alternative stable states is of key importance for the prospects of ecosystem recovery and for management. We show how mechanisms underlying alternative stable states caused by predator–prey interactions can be revealed in field data, using analyses guided by theory on size-structured community dynamics. This is done by combining data on individual performance (such as growth and fecundity) with information on population size and prey availability. We use Atlantic cod (Gadus morhua) and their prey in the Baltic Sea as an example to discuss and distinguish two types of mechanisms, ‘cultivation-depensation’ and ‘overcompensation’, that can cause alternative stable states preventing the recovery of overexploited piscivorous fish populations. Importantly, the type of mechanism can be inferred already from changes in the predators' body growth in different life stages. Our approach can thus be readily applied to monitored stocks of piscivorous fish species, for which this information often can be assembled. Using this tool can help resolve the causes of catastrophic collapses in marine predatory–prey systems and guide fisheries managers on how to successfully restore collapsed piscivorous fish stocks.
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Affiliation(s)
- Anna Gårdmark
- Department of Aquatic Resources, Institute of Coastal Research, Swedish University of Agricultural Sciences, Skolgatan 6, Öregrund 742 42, Sweden
| | - Michele Casini
- Department of Aquatic Resources, Institute of Marine Research, Swedish University of Agricultural Sciences, Turistgatan 5, Lysekil 453 30, Sweden
| | - Magnus Huss
- Department of Aquatic Resources, Institute of Coastal Research, Swedish University of Agricultural Sciences, Skolgatan 6, Öregrund 742 42, Sweden
| | - Anieke van Leeuwen
- Department of Ecology and Evolutionary Biology, Princeton University, 106A Guyot Hall, Princeton, NJ 8544–2016, USA
| | - Joakim Hjelm
- Department of Aquatic Resources, Institute of Marine Research, Swedish University of Agricultural Sciences, Turistgatan 5, Lysekil 453 30, Sweden
| | - Lennart Persson
- Department of Ecology and Environmental Sciences, Umeå University, Umeå 901 87, Sweden
| | - André M. de Roos
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94248, Amsterdam 1090 GE, The Netherlands
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Conversi A, Dakos V, Gårdmark A, Ling S, Folke C, Mumby PJ, Greene C, Edwards M, Blenckner T, Casini M, Pershing A, Möllmann C. A holistic view of marine regime shifts. Philos Trans R Soc Lond B Biol Sci 2015; 370:20130279. [PMCID: PMC4247413 DOI: 10.1098/rstb.2013.0279] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023] Open
Abstract
Understanding marine regime shifts is important not only for ecology but also for developing marine management that assures the provision of ecosystem services to humanity. While regime shift theory is well developed, there is still no common understanding on drivers, mechanisms and characteristic of abrupt changes in real marine ecosystems. Based on contributions to the present theme issue, we highlight some general issues that need to be overcome for developing a more comprehensive understanding of marine ecosystem regime shifts. We find a great divide between benthic reef and pelagic ocean systems in how regime shift theory is linked to observed abrupt changes. Furthermore, we suggest that the long-lasting discussion on the prevalence of top-down trophic or bottom-up physical drivers in inducing regime shifts may be overcome by taking into consideration the synergistic interactions of multiple stressors, and the special characteristics of different ecosystem types. We present a framework for the holistic investigation of marine regime shifts that considers multiple exogenous drivers that interact with endogenous mechanisms to cause abrupt, catastrophic change. This framework takes into account the time-delayed synergies of these stressors, which erode the resilience of the ecosystem and eventually enable the crossing of ecological thresholds. Finally, considering that increased pressures in the marine environment are predicted by the current climate change assessments, in order to avoid major losses of ecosystem services, we suggest that marine management approaches should incorporate knowledge on environmental thresholds and develop tools that consider regime shift dynamics and characteristics. This grand challenge can only be achieved through a holistic view of marine ecosystem dynamics as evidenced by this theme issue.
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Affiliation(s)
- Alessandra Conversi
- Institute of Marine Sciences, National Research Council of Italy, Forte Santa Teresa, Loc Pozzuolo, Lerici, La Spezia 19032, Italy
- Centre for Marine and Coastal Policy, Marine Institute, Plymouth University, Plymouth PL4 8AA, UK
- SAHFOS, The Laboratory, Citadel Hill, The Hoe, Plymouth PL1 2PB, UK
| | - Vasilis Dakos
- Integrative Ecology Group, Estación Biológica de Doñana (CSIC), Américo Vespucio s/n, Sevilla 41092, Spain
| | - Anna Gårdmark
- Department of Aquatic Resources, Swedish University of Agricultural Sciences, Institute of Coastal Research, Skolgatan 6, Öregrund 742 42, Sweden
| | - Scott Ling
- Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129, HOBART TAS 7001, Tasmania
| | - Carl Folke
- Beijer Institute, Royal Swedish Academy of Sciences, PO Box 50005, Stockholm 104 05, Sweden
- Stockholm Resilience Centre, Stockholm University, Kräftriket 2B, Stockholm 106 91, Sweden
| | - Peter J. Mumby
- Marine Spatial Ecology Lab, School of Biological Sciences and ARC Centre of Excellence for Coral Reef Studies, University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Charles Greene
- Ocean Resources and Ecosystems Program, Cornell University, Ithaca, New York, NY, USA
| | - Martin Edwards
- SAHFOS, The Laboratory, Citadel Hill, The Hoe, Plymouth PL1 2PB, UK
| | - Thorsten Blenckner
- Stockholm Resilience Centre, Stockholm University, Kräftriket 2B, Stockholm 106 91, Sweden
| | - Michele Casini
- Swedish University of Agricultural Sciences, Department of Aquatic Resources, Institute of Marine Research, Turistgatan 5, Lysekil 45330, Sweden
| | - Andrew Pershing
- Gulf of Maine Research Institute, 350 Commercial Street, Portland, ME 04101, USA
| | - Christian Möllmann
- Institute for Hydrobiology and Fisheries Science, University of Hamburg, Grosse Elbstrasse 133, Hamburg 22767, Germany
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