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Sguotti C, Vasilakopoulos P, Tzanatos E, Frelat R. Resilience assessment in complex natural systems. Proc Biol Sci 2024; 291:20240089. [PMID: 38807517 DOI: 10.1098/rspb.2024.0089] [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: 09/18/2023] [Accepted: 04/09/2024] [Indexed: 05/30/2024] Open
Abstract
Ecological resilience is the capability of an ecosystem to maintain the same structure and function and avoid crossing catastrophic tipping points (i.e. undergoing irreversible regime shifts). While fundamental for management, concrete ways to estimate and interpret resilience in real ecosystems are still lacking. Here, we develop an empirical approach to estimate resilience based on the stochastic cusp model derived from catastrophe theory. The cusp model models tipping points derived from a cusp bifurcation. We extend cusp in order to identify the presence of stable and unstable states in complex natural systems. Our Cusp Resilience Assessment (CUSPRA) has three characteristics: (i) it provides estimates on how likely a system is to cross a tipping point (in the form of a cusp bifurcation) characterized by hysteresis, (ii) it assesses resilience in relation to multiple external drivers and (iii) it produces straightforward results for ecosystem-based management. We validate our approach using simulated data and demonstrate its application using empirical time series of an Atlantic cod population and marine ecosystems in the North Sea and the Mediterranean Sea. We show that Cusp Resilience Assessment is a powerful method to empirically estimate resilience in support of a sustainable management of our constantly adapting ecosystems under global climate change.
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Affiliation(s)
- Camilla Sguotti
- Department of Biology, University of Padova , Padova 35100, Italy
- Institute of Marine Ecosystems and Fishery Science (IMF), Center for Earth System Research and Sustainability (CEN), University of Hamburg , Hamburg 22767, Germany
| | | | | | - Romain Frelat
- PO Box 30709, International Livestock Research Institute , Nairobi 00100, Kenya
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2
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Hua T, He L, Jiang Q, Chou LM, Xu Z, Yao Y, Ye G. Spatio-temporal coupling analysis and tipping points detection of China's coastal integrated land-human activity-ocean system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 914:169981. [PMID: 38215845 DOI: 10.1016/j.scitotenv.2024.169981] [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: 10/22/2023] [Revised: 12/10/2023] [Accepted: 01/05/2024] [Indexed: 01/14/2024]
Abstract
The coastal zone is typically highly developed and its ocean environment is vastly exposed to the onshore activities. Land-based pollution, as the "metabolite" of terrestrial human activities, significantly impacts the ocean environment. Although numerous studies have investigated these effects, few have quantified the interactions among land-human activity-ocean across both spatial and temporal scales. In this study, we have developed a land-human activity-ocean systemic framework integrating the coupling coordination degree model and tipping point to quantify the spatiotemporal dynamic interaction mechanism among the land-based pollution, human activities, and ocean environment in China from 2001 to 2020. Our findings revealed that the overall coupling coordination degree of the China's coastal zone increased by 36.9 % over last two decades. Furthermore, the effect of human activities on China's coastal environment remained within acceptable thresholds, as no universal tipping points for coastal pollution or ocean environment has been found over the 20-year period. Notably, the lag time for algal blooms, the key indicator of ocean environment health, was found to be 0-3 years in response to the land economic development and 0-4 years in response to land-based pollution. Based on the differences in spatiotemporal interactions among land-human activity-ocean system, we employed cluster analysis to categorize China's coastal provinces into four types and to develop appropriate management measures. Quantifying the interaction mechanism within the land-human activity-ocean system could aid decision-makers in creating sustainable coastal development strategies. This enables efficient use of land and ocean resources, supports coastal conservation and restoration efforts, and fosters effective management recommendations to enhance coastal sustainability and resilience.
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Affiliation(s)
- Tianran Hua
- Ocean College, Zhejiang University, Zhoushan, Zhejiang, China; Hainan Institute of Zhejiang University, Sanya, Hainan, China
| | - Liuyue He
- Ocean College, Zhejiang University, Zhoushan, Zhejiang, China; Donghai Laboratory, Zhoushan, Zhejiang, China
| | - Qutu Jiang
- Department of Geography, The University of Hong Kong, Hong Kong
| | | | - Zhenci Xu
- Department of Geography, The University of Hong Kong, Hong Kong
| | - Yanming Yao
- Ocean College, Zhejiang University, Zhoushan, Zhejiang, China
| | - Guanqiong Ye
- Ocean College, Zhejiang University, Zhoushan, Zhejiang, China; Hainan Institute of Zhejiang University, Sanya, Hainan, China; Second Institute of Oceanography of MNR, Hanghou, Zhejiang, China.
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3
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Garcia AG, Mesquita Filho W, Flechtmann CAH, Lockwood JL, Bonachela JA. Alternative stable ecological states observed after a biological invasion. Sci Rep 2022; 12:20830. [PMID: 36460722 PMCID: PMC9718761 DOI: 10.1038/s41598-022-24367-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 11/14/2022] [Indexed: 12/05/2022] Open
Abstract
Although biological invasions play an important role in ecosystem change worldwide, little is known about how invasions are influenced by local abiotic stressors. Broadly, abiotic stressors can cause large-scale community changes in an ecosystem that influence its resilience. The possibility for these stressors to increase as global changes intensify highlights the pressing need to understand and characterize the effects that abiotic drivers may have on the dynamics and composition of a community. Here, we analyzed 26 years of weekly abundance data using the theory of regime shifts to understand how the structure of a resident community of dung beetles (composed of dweller and tunneler functional groups) responds to climatic changes in the presence of the invasive tunneler Digitonthophagus gazella. Although the community showed an initial dominance by the invader that decreased over time, the theory of regime shifts reveals the possibility of an ecological transition driven by climate factors (summarized here in a climatic index that combines minimum temperature and relative humidity). Mid and low values of the driver led to the existence of two alternative stable states for the community structure (i.e. dominance of either dwellers or tunnelers for similar values of the climatic driver), whereas large values of the driver led to the single dominance by tunnelers. We also quantified the stability of these states against climatic changes (resilience), which provides insight on the conditions under which the success of an invasion and/or the recovery of the previous status quo for the ecosystem are expected. Our approach can help understand the role of climatic changes in community responses, and improve our capacity to deal with regime shifts caused by the introduction of exotic species in new ecosystems.
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Affiliation(s)
- Adriano G. Garcia
- grid.430387.b0000 0004 1936 8796Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, 08901 USA
| | - Walter Mesquita Filho
- grid.11899.380000 0004 1937 0722Departamento de Entomologia e Acarologia, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo (USP), Piracicaba, SP CEP 13418-900 Brazil
| | - Carlos A. H. Flechtmann
- grid.410543.70000 0001 2188 478XDepartamento de Fitossanidade, Engenharia Rural e Solos, Faculdade de Engenharia, Universidade Estadual Paulista (UNESP), Ilha Solteira, SP CEP 15385-00 Brazil
| | - Julie L. Lockwood
- grid.430387.b0000 0004 1936 8796Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, 08901 USA
| | - Juan A. Bonachela
- grid.430387.b0000 0004 1936 8796Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, 08901 USA
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4
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Sguotti C, Bischoff A, Conversi A, Mazzoldi C, Möllmann C, Barausse A. Stable landings mask irreversible community reorganizations in an overexploited Mediterranean ecosystem. J Anim Ecol 2022; 91:2465-2479. [PMID: 36415049 DOI: 10.1111/1365-2656.13831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 09/23/2022] [Indexed: 11/24/2022]
Abstract
Cumulative human pressures and climate change can induce nonlinear discontinuous dynamics in ecosystems, known as regime shifts. Regime shifts typically imply hysteresis, a lacking or delayed system response when pressures are reverted, which can frustrate restoration efforts. Here, we investigate whether the northern Adriatic Sea fish and macroinvertebrate community, as depicted by commercial fishery landings, has undergone regime shifts over the last 40 years, and the reversibility of such changes. We use a stochastic cusp model to show that, under the interactive effect of fishing pressure and water warming, the community reorganized through discontinuous changes. We found that part of the community has now reached a new stable state, implying that a recovery towards previous baselines might be impossible. Interestingly, total landings remained constant across decades, masking the low resilience of the community. Our study reveals the importance of carefully assessing regime shifts and resilience in marine ecosystems under cumulative pressures and advocates for their inclusion into management.
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Affiliation(s)
- Camilla Sguotti
- Institute for Marine Ecosystem and Fisheries Science (IFM), Center for Earth System Research and Sustainability (CEN), University of Hamburg, Hamburg, Germany.,Department of Biology, University of Padova, Padova, Italy
| | - Aurelia Bischoff
- Institute for Marine Ecosystem and Fisheries Science (IFM), Center for Earth System Research and Sustainability (CEN), University of Hamburg, Hamburg, Germany
| | - Alessandra Conversi
- National Research Council of Italy, Marine Science Institute, CNR - ISMAR - LERICI, Forte Santa Teresa, Lerici, SP, Italy
| | - Carlotta Mazzoldi
- Department of Biology, University of Padova, Padova, Italy.,CoNISMa, National Inter-University Consortium for Marine Sciences, Rome, Italy
| | - Christian Möllmann
- Institute for Marine Ecosystem and Fisheries Science (IFM), Center for Earth System Research and Sustainability (CEN), University of Hamburg, Hamburg, Germany
| | - Alberto Barausse
- Department of Biology, University of Padova, Padova, Italy.,CoNISMa, National Inter-University Consortium for Marine Sciences, Rome, Italy
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5
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Durant JM, Ono K, Langangen Ø. Empirical evidence of nonlinearity in bottom up effect in a marine predator-prey system. Biol Lett 2022; 18:20220309. [PMID: 36321432 PMCID: PMC9627449 DOI: 10.1098/rsbl.2022.0309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The strength of species interactions may have profound effects on population dynamics. Empirical estimates of interaction strength are often based on the assumption that the interaction strengths are constant. Barents Sea (BS) cod and capelin are two fish populations for which such an interaction has been acknowledged and used, under the assumption of constant interaction strength, when studying their population dynamics. However, species interactions can often be nonlinear in marine ecosystems and might profoundly change our understanding of food chains. Analysing long-term time series data comprising a survey over 37 years in the Arcto-boreal BS, using a state-space modelling framework, we demonstrate that the effect of capelin on cod is not linear but shifts depending on capelin abundance: while capelin is beneficial for cod populations at high abundance; below the threshold, it becomes less important for cod. Our analysis therefore shows the importance of investigating nonlinearity in species interactions and may contribute to an improved understanding on species assemblages.
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Affiliation(s)
- Joël M. Durant
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, NO-0316 Oslo, Norway
| | - Kotaro Ono
- Institute for Marine Research (IMR), PO Box 1870 Nordnes, Bergen 5817, Norway
| | - Øystein Langangen
- Section for Aquatic Biology and Toxicology (AQUA), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, NO-0316 Oslo, Norway
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Jarillo J, Cao-García FJ, De Laender F. Spatial and Ecological Scaling of Stability in Spatial Community Networks. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.861537] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
There are many scales at which to quantify stability in spatial and ecological networks. Local-scale analyses focus on specific nodes of the spatial network, while regional-scale analyses consider the whole network. Similarly, species- and community-level analyses either account for single species or for the whole community. Furthermore, stability itself can be defined in multiple ways, including resistance (the inverse of the relative displacement caused by a perturbation), initial resilience (the rate of return after a perturbation), and invariability (the inverse of the relative amplitude of the population fluctuations). Here, we analyze the scale-dependence of these stability properties. More specifically, we ask how spatial scale (local vs. regional) and ecological scale (species vs. community) influence these stability properties. We find that regional initial resilience is the weighted arithmetic mean of the local initial resiliences. The regional resistance is the harmonic mean of local resistances, which makes regional resistance particularly vulnerable to nodes with low stability, unlike regional initial resilience. Analogous results hold for the relationship between community- and species-level initial resilience and resistance. Both resistance and initial resilience are “scale-free” properties: regional and community values are simply the biomass-weighted means of the local and species values, respectively. Thus, one can easily estimate both stability metrics of whole networks from partial sampling. In contrast, invariability generally is greater at the regional and community-level than at the local and species-level, respectively. Hence, estimating the invariability of spatial or ecological networks from measurements at the local or species level is more complicated, requiring an unbiased estimate of the network (i.e., region or community) size. In conclusion, we find that scaling of stability depends on the metric considered, and we present a reliable framework to estimate these metrics.
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7
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Tirronen M, Perälä T, Kuparinen A. Temporary Allee effects among non-stationary recruitment dynamics in depleted gadid and flatfish populations. FISH AND FISHERIES (OXFORD, ENGLAND) 2022; 23:392-406. [PMID: 35875511 PMCID: PMC9298083 DOI: 10.1111/faf.12623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 09/28/2021] [Accepted: 10/05/2021] [Indexed: 06/15/2023]
Abstract
Many considerably declined fish populations have not fully recovered despite reductions in fishing pressure. One of the possible causes of impaired recovery is the (demographic) Allee effect. To investigate whether low-abundance recruitment dynamics can switch between compensation and depensation, the latter implying the presence of the Allee effect, we analysed the stock-recruitment time series of 17 depleted cod-type and flatfish populations using a Bayesian change point model. The recruitment dynamics were represented with the sigmoidal Beverton-Holt and the Saila-Lorda stock-recruitment models, allowing the parameters of the models to shift at a priori unknown change points. Our synthesis study questions the common assumption that recruitment is stationary and compensatory and the high amount of scatteredness often present in stock-recruitment data is only due to random variation. When a moderate amount of such variation was assumed, stock-recruitment dynamics were best explained by a non-stationary model for 53% of the populations, which suggests that these populations exhibit temporal changes in the stock-recruitment relationship. For four populations, we found shifts between compensation and depensation, suggesting the presence of temporary Allee effects. However, the evidence of Allee effects was highly dependent on the priors of the stock-recruitment model parameters and the amount of random variation assumed. Nonetheless, detection of changes in low-abundance recruitment is essential in stock assessment since such changes affect the renewal ability of the population and, ultimately, its sustainable harvest limits.
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Affiliation(s)
- Maria Tirronen
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
| | - Tommi Perälä
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
| | - Anna Kuparinen
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
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8
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Hidalgo M, Vasilakopoulos P, García-Ruiz C, Esteban A, López-López L, García-Gorriz E. Resilience dynamics and productivity-driven shifts in the marine communities of the Western Mediterranean Sea. J Anim Ecol 2021; 91:470-483. [PMID: 34873693 PMCID: PMC9300018 DOI: 10.1111/1365-2656.13648] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 11/29/2021] [Indexed: 11/29/2022]
Abstract
Ecological resilience has become a conceptual cornerstone bridging ecological processes to conservation needs. Global change is increasingly associated with local changes in environmental conditions that can cause abrupt ecosystem reorganizations attending to system‐specific resilience fluctuations with time (i.e. resilience dynamics). Here we assess resilience dynamics associated with climate‐driven ecosystems transitions, expressed as changes in the relevant contribution of species with different life‐history strategies, in two benthopelagic systems. We analysed data from 1994 to 2019 coming from a scientific bottom trawl survey in two environmentally contrasting ecosystems in the Western Mediterranean Sea—Northern Spain and Alboran Sea. Benthopelagic species were categorized according to their life‐history strategies (opportunistic, periodic and equilibrium), ecosystem functions and habitats. We implemented an Integrated Resilience Assessment (IRA) to elucidate the response mechanism of the studied ecosystems to several candidate environmental stressors and quantify the ecosystems’ resilience. We demonstrate that both ecosystems responded discontinuously to changes in chlorophyll‐a concentration more than any other stressor. The response in Northern Spain indicated a more overarching regime shift than in the Alboran Sea. Opportunistic fish were unfavoured in both ecosystems in the recent periods, while invertebrate species of short life cycle were generally favoured, particularly benthic species in the Alboran Sea. The study illustrates that the resilience dynamics of the two ecosystems were mostly associated with fluctuating productivity, but subtle and long‐term effects from sea warming and fishing reduction were also discernible. Such dynamics are typical of systems with wide environmental gradient such as the Northern Spain, as well as systems with highly hydrodynamic and of biogeographical complexity such as the Alboran Sea. We stress that management should become more adaptive by utilizing the knowledge on the systems’ productivity thresholds and underlying shifts to help anticipate both short‐term/less predictable events and long‐term/expected effects of climate change.
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Affiliation(s)
- Manuel Hidalgo
- Instituto Español de Oceanografía (IEO, CSIC), Centro Oceanográfico de Baleares (COB), Ecosystem Oceanography Group (GRECO), Palma, Balearic Islands, Spain
| | | | - Cristina García-Ruiz
- Instituto Español de Oceanografía (IEO, CSIC), Centro Oceanográfico de Málaga, Fuengirola, Málaga, Spain
| | - Antonio Esteban
- Instituto Español de Oceanografía (IEO, CSIC), Centro Oceanográfico de Murcia, San Pedro del Pinar, Murcia, Spain
| | - Lucía López-López
- Instituto Español de Oceanografía (IEO, CSIC), Centro Oceanográfico de Baleares (COB), Ecosystem Oceanography Group (GRECO), Palma, Balearic Islands, Spain
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9
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Durant JM, Aarvold L, Langangen Ø. Stock collapse and its effect on species interactions: Cod and herring in the Norwegian-Barents Seas system as an example. Ecol Evol 2021; 11:16993-17004. [PMID: 34938487 PMCID: PMC8668721 DOI: 10.1002/ece3.8336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 10/19/2021] [Accepted: 10/22/2021] [Indexed: 11/25/2022] Open
Abstract
Both the Norwegian Spring Spawning herring (Clupea harengus) and the Northeast Arctic (NEA) cod (Gadus morhua) are examples of strong stock reduction and decline of the associated fisheries due to overfishing followed by a recovery. Cod and herring are both part of the Barents Sea ecosystem, which has experienced major warming events in the early (1920-1940) and late 20th century. While the collapse or near collapse of these stocks seems to be linked to an instability created by overfishing and climate, the difference of population dynamics before and after is not fully understood. In particular, it is unclear how the changes in population dynamics before and after the collapses are associated with biotic interactions. The combination of the availability of unique long-term time series for herring and cod makes it a well-suited study system to investigate the effects of collapse. We examine how species interactions may differently affect the herring and cod population dynamic before and after a collapse. Particularly we explore, using a GAM modeling approach, how herring could affect cod and vice versa. We found that the effect of cod biomass on herring that was generally positive (i.e., covariation) but the effect became negative after the collapse (i.e., predation or competition). Likewise a change occurred for the cod, the juvenile herring biomass that had no effect before the collapse had a negative effect after. Our results indicate that the population collapses may alter the inter-specific interactions and response to abiotic environmental changes. While the stocks are at similar abundance levels before and after the collapses, the system is potentially different in its functioning and may require different management action.
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Affiliation(s)
- Joël M. Durant
- Centre for Ecological and Evolutionary Synthesis (CEES)Department of BiosciencesUniversity of OsloOsloNorway
| | - Leana Aarvold
- Centre for Ecological and Evolutionary Synthesis (CEES)Department of BiosciencesUniversity of OsloOsloNorway
| | - Øystein Langangen
- Section for Aquatic biology and toxicology (AQUA)Department of BiosciencesUniversity of OsloOsloNorway
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Damalas D, Sgardeli V, Vasilakopoulos P, Tserpes G, Maravelias C. Evidence of climate-driven regime shifts in the Aegean Sea's demersal resources: A study spanning six decades. Ecol Evol 2021; 11:16951-16971. [PMID: 34938484 PMCID: PMC8668738 DOI: 10.1002/ece3.8330] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 09/03/2021] [Accepted: 10/14/2021] [Indexed: 11/17/2022] Open
Abstract
Climate change (CC) can alter the configuration of marine ecosystems; however, ecosystem response and resilience to change are usually case-specific. The effect of CC on the demersal resources of the Aegean Sea (east Mediterranean Sea) was investigated during the past six decades applying a combination of multivariate analysis, non-additive modeling and the Integrated Resilience Assessment (IRA) framework. We focused on the study of: (i) the biological "system" complex, using proxies of biomass (landings per unit of capacity) for 12 demersal taxa, and (ii) the environmental "stressor" complex, described by 12 abiotic variables. Pronounced changes have occurred in both the environmental and biological system over the studied period. The majority of the environmental stressors exhibited strikingly increasing trends (temperature, salinity, primary production indices) with values started exceeding the global historical means during late 1980s-early 1990s. It is suggested that the biological system exhibited a discontinuous response to CC, with two apparently climate-induced regime shifts occurring in the past 25 years. There is evidence for two-fold bifurcations and four tipping points in the system, forming a folded stability landscape with three basins of attraction. The shape of the stability landscape for the Aegean Sea's biological system suggests that while the initial state (1966-1991) was rather resilient to CC, absorbing two environmental step-changes, this was not the case for the two subsequent ones (intermediate: 1992-2002; recent: 2003-2016). Given the current trajectory of environmental change, it is highly unlikely that the biological system will ever return to its pre-1990s state, as it is entering areas of unprecedented climatic conditions and there is some evidence that the system may be even shifting toward a new state. Our approach and findings may be relevant to other marine areas of the Mediterranean and beyond, undergoing climate-driven regime shifts, and can assist to their adaptive management.
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Affiliation(s)
- Dimitrios Damalas
- Hellenic Centre for Marine ResearchInstitute of Marine Biological Resources and Inland WatersHeraklionGreece
| | - Vasiliki Sgardeli
- Hellenic Centre for Marine ResearchInstitute of Marine Biological Resources and Inland WatersHeraklionGreece
| | | | - Georgios Tserpes
- Hellenic Centre for Marine ResearchInstitute of Marine Biological Resources and Inland WatersHeraklionGreece
| | - Christos Maravelias
- Department of Ichthyology and Aquatic EnvironmentUniversity of ThessalyVolosGreece
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Ma S, Liu D, Tian Y, Fu C, Li J, Ju P, Sun P, Ye Z, Liu Y, Watanabe Y. Critical transitions and ecological resilience of large marine ecosystems in the Northwestern Pacific in response to global warming. GLOBAL CHANGE BIOLOGY 2021; 27:5310-5328. [PMID: 34309964 DOI: 10.1111/gcb.15815] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 07/04/2021] [Accepted: 07/20/2021] [Indexed: 06/13/2023]
Abstract
Natural systems can undergo critical transitions, leading to substantial socioeconomic and ecological outcomes. "Ecological resilience" has been proposed to describe the capacity of natural systems to absorb external perturbation and reorganize while undergoing change so as to still retain essentially the same function, structure, identity, and feedbacks. However, the mere application of ecological resilience in theoretical research and the lack of quantitative approaches present considerable obstacles for predicting critical transitions and understanding their mechanisms. Large marine ecosystems (LMEs) in the Northwestern Pacific are characterized by great biodiversity and productivity, as well as remarkable warming in recent decades. However, no information is available on the critical transitions and ecological resilience of LMEs in response to warming. Therefore, we applied an integrated resilience assessment framework to fisheries catch data from seven LMEs covering a wide range of regions, from tropical to subarctic, in the Northwestern Pacific to identify critical transitions, assess ecological resilience, and reconstruct folded stability landscapes, with a specific focus on the effects of warming. The results provide evidence of the occurrence of critical transitions, with fold bifurcation and hysteresis in response to increasing sea surface temperatures (SSTs) in the seven LMEs. In addition, these LMEs show similarities and synchronies in structure variations and critical transitions forced by warming. Both dramatic increases in SST and small fluctuations at the corresponding thresholds may trigger critical transitions. Ecological resilience decreases when approaching the tipping points and is repainted as the LMEs shift to alternative stable states with different resilient dynamics. Folded stability landscapes indicate that the responses of LMEs to warming are discontinuous, which may be caused by the reorganization of LMEs as their sensitivity to warming changes. Our study clarifies the nonlinear responses of LMEs to anthropogenic warming and provides examples of quantifying ecological resilience in empirical systems at unprecedented spatial and temporal scales.
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Affiliation(s)
- Shuyang Ma
- Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, China
| | - Dan Liu
- Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, China
| | - Yongjun Tian
- Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
| | - Caihong Fu
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, Canada
| | - Jianchao Li
- Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, China
| | - Peilong Ju
- Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, China
| | - Peng Sun
- Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, China
| | - Zhenjiang Ye
- Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, China
| | - Yang Liu
- Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
| | - Yoshiro Watanabe
- Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, China
- Atmosphere and Ocean Research Institute, University of Tokyo, Chiba, Japan
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12
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Tsimara E, Vasilakopoulos P, Koutsidi M, Raitsos DE, Lazaris A, Tzanatos E. An Integrated Traits Resilience Assessment of Mediterranean fisheries landings. J Anim Ecol 2021; 90:2122-2134. [PMID: 34013517 DOI: 10.1111/1365-2656.13533] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/14/2021] [Indexed: 11/28/2022]
Abstract
An increasing number of studies have been examining the functional configuration of biological communities or ecosystems using biological traits. Here, we investigated the temporal dynamics and resilience of the traits composition in Mediterranean fisheries landings over 31 years (1985-2015). We transcribed the FAO Mediterranean landings dataset for 101 marine species into a dataset of 23 traits related to the life cycle, distribution, ecology and behaviour. Mediterranean mean Sea Surface Temperature (SST) was evaluated as a potential driver of the traits composition. Trait dynamics were evaluated both individually and holistically by developing an Integrated Traits Resilience Assessment (ITRA). ITRA is a variation of the Integrated Resilience Assessment (IRA), a method to infer resilience dynamics and build stability landscapes of complex natural systems. Changes in landings trait dynamics were documented both for individual traits and for the entire traits 'system', and a relevant regime shift was detected in the second half of the 1990s. The traits system switched to higher optimal temperature, more summer spawning, shorter life span, smaller maximum size, shallower optimal depth and planktivorous diet. This shift was found to be a lagged discontinuous response to sea warming, which gradually eroded the resilience of the original state of the traits system, leading it into a new basin of attraction. The inclusion of ecological/response traits (related to environmental preferences) in our analyses indicates potential mechanisms that explain the observed shift, while changes in functional/effect traits indicate potential impacts on ecosystem functioning. Our findings suggest that changes in the Mediterranean ecosystems are evidently larger than previously thought, with profound implications for the management of this highly impacted sea. .
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Affiliation(s)
- Eleni Tsimara
- Department of Biology, University of Patras, Patras, Greece
| | | | | | - Dionysios E Raitsos
- Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Alexis Lazaris
- Department of Biology, University of Patras, Patras, Greece
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13
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Smoliński S, Denechaud C, von Leesen G, Geffen AJ, Grønkjær P, Godiksen JA, Campana SE. Differences in metabolic rate between two Atlantic cod (Gadus morhua) populations estimated with carbon isotopic composition in otoliths. PLoS One 2021; 16:e0248711. [PMID: 33793572 PMCID: PMC8016290 DOI: 10.1371/journal.pone.0248711] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 03/03/2021] [Indexed: 11/18/2022] Open
Abstract
The isotopic composition of inorganic carbon in otoliths (δ13Coto) can be a useful tracer of metabolic rates and a method to study ecophysiology in wild fish. We evaluated environmental and physiological sources of δ13Coto variation in Icelandic and Northeast Arctic (NEA) cod (Gadus morhua) over the years 1914–2013. Individual annual growth increments of otoliths formed at age 3 and 8 were micromilled and measured by isotope-ratio mass spectrometry. Simultaneously, all annual increment widths of the otoliths were measured providing a proxy of fish somatic growth. We hypothesized that changes in the physiological state of the organism, reflected by the isotopic composition of otoliths, can affect the growth rate. Using univariate and multivariate mixed-effects models we estimated conditional correlations between carbon isotopic composition and growth of fish at different levels (within individuals, between individuals, and between years), controlling for intrinsic and extrinsic effects on both otolith measurements. δ13Coto was correlated with growth within individuals and between years, which was attributed to the intrinsic effects (fish age or total length). There was no significant correlation between δ13Coto and growth between individuals, which suggests that caution is needed when interpreting δ13Coto signals. We found a significant decrease in δ13Coto through the century which was explained by the oceanic Suess effect-admixture of isotopically light carbon from fossil fuel. We calculated the proportion of the respired carbon in otolith carbonate (Cresp) using carbon isotopic composition in diet and dissolved inorganic carbon of the seawater. This approach allowed us to correct the values for each stock in relation to these two environmental baselines. Cresp was on average 0.275 and 0.295 in Icelandic and NEA stock, respectively. Our results provide an insight into the physiological basis for differences in growth characteristics between these two cod stocks, and how that may vary over time.
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Affiliation(s)
- Szymon Smoliński
- Institute of Marine Research, Nordnes, Bergen, Norway
- Department of Fisheries Resources, National Marine Fisheries Research Institute, Gdynia, Poland
- * E-mail:
| | - Côme Denechaud
- Institute of Marine Research, Nordnes, Bergen, Norway
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Gotje von Leesen
- Faculty of Life and Environmental Sciences, University of Iceland, Reykjavik, Iceland
| | - Audrey J. Geffen
- Institute of Marine Research, Nordnes, Bergen, Norway
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Peter Grønkjær
- Aquatic Biology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | | | - Steven E. Campana
- Faculty of Life and Environmental Sciences, University of Iceland, Reykjavik, Iceland
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14
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Durant JM, Ono K, Stenseth NC, Langangen Ø. Nonlinearity in interspecific interactions in response to climate change: Cod and haddock as an example. GLOBAL CHANGE BIOLOGY 2020; 26:5554-5563. [PMID: 32623765 DOI: 10.1111/gcb.15264] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/14/2020] [Accepted: 06/25/2020] [Indexed: 06/11/2023]
Abstract
Climate change has profound ecological effects, yet our understanding of how trophic interactions among species are affected by climate change is still patchy. The sympatric Atlantic haddock and cod are co-occurring across the North Atlantic. They compete for food at younger stages and thereafter the former is preyed by the latter. Climate change might affect the interaction and coexistence of these two species. Particularly, the increase in sea temperature (ST) has been shown to affect distribution, population growth and trophic interactions in marine systems. We used 33-year long time series of haddock and cod abundances estimates from two data sources (acoustic and trawl survey) to analyse the dynamic effect of climate on the coexistence of these two sympatric species in the Arcto-Boreal Barents Sea. Using a Bayesian state-space threshold model, we demonstrated that long-term climate variation, as expressed by changes of ST, affected species demography through different influences on density-independent processes. The interaction between cod and haddock has shifted in the last two decades due to an increase in ST, altering the equilibrium abundances and the dynamics of the system. During warm years (ST over ca. 4°C), the increase in the cod abundance negatively affected haddock abundance while it did not during cold years. This change in interactions therefore changed the equilibrium population size with a higher population size during warm years. Our analyses show that long-term climate change in the Arcto-Boreal system can generate differences in the equilibrium conditions of species assemblages.
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Affiliation(s)
- Joël M Durant
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Kotaro Ono
- Institute for Marine Research (IMR), Bergen, Norway
| | - Nils Chr Stenseth
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Coastal Research (CCR), Department of Natural Sciences, University of Agder, Kristiansand, Norway
| | - Øystein Langangen
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
- Section for Aquatic Biology and Toxicology (AQUA), Department of Biosciences, University of Oslo, Oslo, Norway
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15
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Sguotti C, Otto SA, Frelat R, Langbehn TJ, Ryberg MP, Lindegren M, Durant JM, Chr Stenseth N, Möllmann C. Catastrophic dynamics limit Atlantic cod recovery. Proc Biol Sci 2020; 286:20182877. [PMID: 30862289 PMCID: PMC6458326 DOI: 10.1098/rspb.2018.2877] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Collapses and regime changes are pervasive in complex systems (such as marine ecosystems) governed by multiple stressors. The demise of Atlantic cod (Gadus morhua) stocks constitutes a text book example of the consequences of overexploiting marine living resources, yet the drivers of these nearly synchronous collapses are still debated. Moreover, it is still unclear why rebuilding of collapsed fish stocks such as cod is often slow or absent. Here, we apply the stochastic cusp model, based on catastrophe theory, and show that collapse and recovery of cod stocks are potentially driven by the specific interaction between exploitation pressure and environmental drivers. Our statistical modelling study demonstrates that for most of the cod stocks, ocean warming could induce a nonlinear discontinuous relationship between fishing pressure and stock size, which would explain hysteresis in their response to reduced exploitation pressure. Our study suggests further that a continuing increase in ocean temperatures will probably limit productivity and hence future fishing opportunities for most cod stocks of the Atlantic Ocean. Moreover, our study contributes to the ongoing discussion on the importance of climate and fishing effects on commercially exploited fish stocks, highlighting the importance of considering discontinuous dynamics in holistic ecosystem-based management approaches, particularly under climate change.
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Affiliation(s)
- Camilla Sguotti
- 1 Institute for Marine Ecosystem and Fisheries Science (IMF), Center for Earth System Research and Sustainability (CEN), University of Hamburg , 22767 Hamburg , Germany
| | - Saskia A Otto
- 1 Institute for Marine Ecosystem and Fisheries Science (IMF), Center for Earth System Research and Sustainability (CEN), University of Hamburg , 22767 Hamburg , Germany
| | - Romain Frelat
- 1 Institute for Marine Ecosystem and Fisheries Science (IMF), Center for Earth System Research and Sustainability (CEN), University of Hamburg , 22767 Hamburg , Germany
| | - Tom J Langbehn
- 2 Department of Biological Sciences, University of Bergen , 5006 Bergen , Norway
| | - Marie Plambech Ryberg
- 3 National Institute of Aquatic Resources, Technical University of Denmark (DTU Aqua) , 2800 Kgs Lyngby , Denmark
| | - Martin Lindegren
- 3 National Institute of Aquatic Resources, Technical University of Denmark (DTU Aqua) , 2800 Kgs Lyngby , Denmark
| | - Joël M Durant
- 4 Department of Biosciences, Centre for Ecological and Evolutionary Synthesis (CEES), University of Oslo , 0316 Oslo , Norway
| | - Nils Chr Stenseth
- 4 Department of Biosciences, Centre for Ecological and Evolutionary Synthesis (CEES), University of Oslo , 0316 Oslo , Norway
| | - Christian Möllmann
- 1 Institute for Marine Ecosystem and Fisheries Science (IMF), Center for Earth System Research and Sustainability (CEN), University of Hamburg , 22767 Hamburg , Germany
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16
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Abstract
The replacement of forest areas with human-dominated landscapes usually leads to fragmentation, altering the structure and function of the forest. Here we studied the dynamics of forest patch sizes at a global level, examining signals of a critical transition from an unfragmented to a fragmented state, using the MODIS vegetation continuous field. We defined wide regions of connected forest across continents and big islands, and combined five criteria, including the distribution of patch sizes and the fluctuations of the largest patch over the last sixteen years, to evaluate the closeness of each region to a fragmentation threshold. Regions with the highest deforestation rates-South America, Southeast Asia, Africa-all met these criteria and may thus be near a critical fragmentation threshold. This implies that if current forest loss rates are maintained, wide continental areas could suddenly fragment, triggering extensive species loss and degradation of ecosystems services.
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17
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Chevalier M, Grenouillet G. Global assessment of early warning signs that temperature could undergo regime shifts. Sci Rep 2018; 8:10058. [PMID: 29968797 PMCID: PMC6030089 DOI: 10.1038/s41598-018-28386-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 06/15/2018] [Indexed: 11/09/2022] Open
Abstract
Climate change metrics have been used to quantify the exposure of geographic areas to different facets of change and relate these facets to different threats and opportunities for biodiversity at a global scale. In parallel, a suite of indicators have been developed to detect approaching transitions between alternative stable states in ecological systems at a local scale. Here, we explore whether particular geographic areas over the world display evidence for upcoming critical transitions in the temperature regime using five Early Warning Indicators (EWIs) commonly used in the literature. Although all EWIs revealed strong spatial variations regarding the likelihood of approaching transitions we found differences regarding the strength and the distribution of trends across the world, suggesting either that different mechanisms might be at play or that EWIs differ in their ability to detect approaching transitions. Nonetheless, a composite EWI, constructed from individual EWIs, showed congruent trends in several areas and highlighted variations across latitudes, between marine and terrestrial systems and among ecoregions within systems. Although the underlying mechanisms are unclear, our results suggest that some areas over the world might change toward an alternative temperature regime in the future with potential implications for the organisms inhabiting these areas.
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Affiliation(s)
- Mathieu Chevalier
- CNRS, Université Toulouse III Paul Sabatier, ENFA; UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), 118 route de Narbonne, F-31062, Toulouse, France.
- Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, 750 07, Uppsala, Sweden.
| | - Gaël Grenouillet
- CNRS, Université Toulouse III Paul Sabatier, ENFA; UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), 118 route de Narbonne, F-31062, Toulouse, France
- Institut Universitaire de France, Paris, France
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18
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Ratajczak Z, Carpenter SR, Ives AR, Kucharik CJ, Ramiadantsoa T, Stegner MA, Williams JW, Zhang J, Turner MG. Abrupt Change in Ecological Systems: Inference and Diagnosis. Trends Ecol Evol 2018; 33:513-526. [PMID: 29784428 DOI: 10.1016/j.tree.2018.04.013] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 04/21/2018] [Accepted: 04/23/2018] [Indexed: 02/07/2023]
Abstract
Abrupt ecological changes are, by definition, those that occur over short periods of time relative to typical rates of change for a given ecosystem. The potential for such changes is growing due to anthropogenic pressures, which challenges the resilience of societies and ecosystems. Abrupt ecological changes are difficult to diagnose because they can arise from a variety of circumstances, including rapid changes in external drivers (e.g., climate, or resource extraction), nonlinear responses to gradual changes in drivers, and interactions among multiple drivers and disturbances. We synthesize strategies for identifying causes of abrupt ecological change and highlight instances where abrupt changes are likely. Diagnosing abrupt changes and inferring causation are increasingly important as society seek to adapt to rapid, multifaceted environmental changes.
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Affiliation(s)
- Zak Ratajczak
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | - Stephen R Carpenter
- Center for Limnology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Anthony R Ives
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | | | - Tanjona Ramiadantsoa
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - M Allison Stegner
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - John W Williams
- Department of Geography and Center for Climatic Research, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Jien Zhang
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Monica G Turner
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA.
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19
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20
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Clements CF, Ozgul A. Indicators of transitions in biological systems. Ecol Lett 2018; 21:905-919. [PMID: 29601665 DOI: 10.1111/ele.12948] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 11/22/2017] [Accepted: 02/22/2018] [Indexed: 12/13/2022]
Abstract
In the face of global biodiversity declines, predicting the fate of biological systems is a key goal in ecology. One popular approach is the search for early warning signals (EWSs) based on alternative stable states theory. In this review, we cover the theory behind nonlinearity in dynamic systems and techniques to detect the loss of resilience that can indicate state transitions. We describe the research done on generic abundance-based signals of instability that are derived from the phenomenon of critical slowing down, which represent the genesis of EWSs research. We highlight some of the issues facing the detection of such signals in biological systems - which are inherently complex and show low signal-to-noise ratios. We then document research on alternative signals of instability, including measuring shifts in spatial autocorrelation and trait dynamics, and discuss potential future directions for EWSs research based on detailed demographic and phenotypic data. We set EWSs research in the greater field of predictive ecology and weigh up the costs and benefits of simplicity vs. complexity in predictive models, and how the available data should steer the development of future methods. Finally, we identify some key unanswered questions that, if solved, could improve the applicability of these methods.
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Affiliation(s)
- Christopher F Clements
- School of Biosciences, The University of Melbourne, Parkville, Vic., 3010, Australia.,Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, 8057, Switzerland
| | - Arpat Ozgul
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, 8057, Switzerland
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21
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Chen N, Jayaprakash C, Yu K, Guttal V. Rising Variability, Not Slowing Down, as a Leading Indicator of a Stochastically Driven Abrupt Transition in a Dryland Ecosystem. Am Nat 2018; 191:E1-E14. [DOI: 10.1086/694821] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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22
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Vasilakopoulos P, Raitsos DE, Tzanatos E, Maravelias CD. Resilience and regime shifts in a marine biodiversity hotspot. Sci Rep 2017; 7:13647. [PMID: 29057946 PMCID: PMC5651905 DOI: 10.1038/s41598-017-13852-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 09/29/2017] [Indexed: 11/09/2022] Open
Abstract
Complex natural systems, spanning from individuals and populations to ecosystems and social-ecological systems, often exhibit abrupt reorganizations in response to changing stressors, known as regime shifts or critical transitions. Theory suggests that such systems feature folded stability landscapes with fluctuating resilience, fold-bifurcations, and alternate basins of attraction. However, the implementation of such features to elucidate response mechanisms in an empirical context is scarce, due to the lack of generic approaches to quantify resilience dynamics in individual natural systems. Here, we introduce an Integrated Resilience Assessment (IRA) framework: a three-step analytical process to assess resilience and construct stability landscapes of empirical systems. The proposed framework involves a multivariate analysis to estimate holistic system indicator variables, non-additive modelling to estimate alternate attractors, and a quantitative resilience assessment to scale stability landscapes. We implement this framework to investigate the temporal development of the Mediterranean marine communities in response to sea warming during 1985–2013, using fisheries landings data. Our analysis revealed a nonlinear tropicalisation of the Mediterranean Sea, expressed as abrupt shifts to regimes dominated by thermophilic species. The approach exemplified here for the Mediterranean Sea, revealing previously unknown resilience dynamics driven by climate forcing, can elucidate resilience and shifts in other complex systems.
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Affiliation(s)
- Paraskevas Vasilakopoulos
- Institute of Marine Biological Resources and Inland Waters, Hellenic Centre for Marine Research (HCMR), 46.7 km Athens-Sounio ave., Anavyssos, 19013, Greece. .,European Commission, Joint Research Centre, Directorate D - Sustainable Resources, Unit D.02 Water and Marine Resources, Via Enrico Fermi 2749, 21027, Ispra (VA), Italy.
| | - Dionysios E Raitsos
- Remote Sensing Group, Plymouth Marine Laboratory (PML), Plymouth, Devon, PL1 3DH, UK.,National Centre for Earth Observation, PML, Plymouth, UK
| | | | - Christos D Maravelias
- Institute of Marine Biological Resources and Inland Waters, Hellenic Centre for Marine Research (HCMR), 46.7 km Athens-Sounio ave., Anavyssos, 19013, Greece
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23
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Clements CF, Ozgul A. Rate of forcing and the forecastability of critical transitions. Ecol Evol 2016; 6:7787-7793. [PMID: 30128129 PMCID: PMC6093161 DOI: 10.1002/ece3.2531] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 09/02/2016] [Accepted: 09/06/2016] [Indexed: 11/21/2022] Open
Abstract
Critical transitions are qualitative changes of state that occur when a stochastic dynamical system is forced through a critical point. Many critical transitions are preceded by characteristic fluctuations that may serve as model‐independent early warning signals, implying that these events may be predictable in applications ranging from physics to biology. In nonbiological systems, the strength of such early warning signals has been shown partly to be determined by the speed at which the transition occurs. It is currently unknown whether biological systems, which are inherently high dimensional and typically display low signal‐to‐noise ratios, also exhibit this property, which would have important implications for how ecosystems are managed, particularly where the forces exerted on a system are anthropogenic. We examine whether the rate of forcing can alter the strength of early warning signals in (1) a model exhibiting a fold bifurcation where a state shift is driven by the harvesting of individuals, and (2) a model exhibiting a transcritical bifurcation where a state shift is driven by increased grazing pressure. These models predict that the rate of forcing can alter the detectability of early warning signals regardless of the underlying bifurcation the system exhibits, but that this result may be more pronounced in fold bifurcations. These findings have important implications for the management of biological populations, particularly harvested systems such as fisheries, and suggest that knowing the class of bifurcations a system will manifest may help discriminate between true‐positive and false‐positive signals.
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Affiliation(s)
- Christopher F Clements
- Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich Switzerland
| | - Arpat Ozgul
- Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich Switzerland
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