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Thermal pollution from the cooling system of the nuclear power plants greatly changes the environmental and the ecological conditions of the receiving marine water body, but we know little about their impact on the steady-state transition of marine bacterioplankton communities. In this study, we used high-throughput sequencing based on the 16S rRNA gene to investigate the impact of the thermal pollution on the bacterioplankton communities in a subtropical bay (the Daya Bay). We observed that thermal pollution from the cooling system of the nuclear power plant caused a pronounced thermal gradient ranging from 19.6°C to 24.12°C over the whole Daya Bay. A temperature difference of 4.5°C between the northern and southern parts of the bay led to a regime shift in the bacterioplankton community structure. In the three typical scenarios of regime shifts, the steady-state transition of bacterioplankton community structure in response to temperature increasing was more likely consistent with an abrupt regime shift rather than a smooth regime or a discontinuous regime model. Water temperature was a decisive factor on the regime shift of bacterioplankton community structure. High temperature significantly decreased bacterioplankton diversity and shifted its community compositions. Cyanobium and Synechococcus of Cyanobacteria, NS5 marine group of Bacteroidota, and Vibrio of Gammaproteobacteria were found that favored high temperature environments. Furthermore, the increased water temperature significantly altered the community assembly of bacterioplankton in Daya Bay, with a substantial decrease in the proportion of drift and others, and a marked increase in the proportion of homogeneous selection. In summary, we proposed that seawater temperature increasing induced by the thermal pollution resulted in an abrupt regime shift of bacterioplankton community in winter subtropical bay. Our research might broad our understanding of marine microbial ecology under future conditions of global warming., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Shan, Chen, Deng, He and Ren.)

Ecosystems respond to climatic and anthropogenic forcings with regime shifts and reorganizations of their system structures. In river basins, changes in sediment transport can have cascading effects that cause ecosystem regime shifts. The Yellow River, once the world's most sediment-rich river, has experienced dramatic regime shifts. Although recent intervention has returned sediment discharge in the Yellow River to pristine levels, our understanding of previous regime shifts remains inadequate, particularly for the regime shift to a sediment rich period during early historical time. We reanalyzed previous datasets to clarify the first historical sediment transport regime shift in the Yellow River. Our results show that while historical climatic changes (e.g., the Medieval Warm Period, about 900–1100 AD) caused changes in sediment transport, a regime shift occurred only under increased forcing from anthropogenic stresses (started from about 1350 AD, reached the tipping point after 1900 AD). This unique behavior of the Yellow River under increasing anthropogenic forces may provide perspective for sustainable river basin management. [ABSTRACT FROM AUTHOR]

The small, shallow lake Littoistenjärvi (SW Finland) experienced in 1978–2019 rapid fluctuations between extreme ecological states, initially associated with mass occurrences of the submerged macrophyte Elodea canadensis Michx. In collapse years following abundance peaks, water was turbid, in other years clear. Aeration prevented anoxia under ice-cover, but this favoured Elodea. Mechanical plant removal accelerated Elodea growth, and had to be abandoned. Recurrent cyanobacterial blooms started in 2000, and by 2006 phosphorus and chlorophyll reached new high levels because of increased internal loading. During this turbid state, internal loading showed significant positive correlation with maximum water temperature and pH. External loading was reduced in 2011 by one-third by diverting runoff from a former arable field transformed into a wetland. Precipitation of phosphorus with polyaluminium chloride in 2017 restored the clear-water state. The case of Littoistenjärvi shows that if internal loading has become the major factor controlling water quality, traditional restoration methods (external load reduction, aeration, removal fishing) provide limited possibilities to improve water quality. Instead, chemical precipitation of phosphorus seems a promising measure which can break the vicious circle of algal blooms and internal loading. Unfortunately, the uncontrollable growth of invasive submerged macrophytes may jeopardise the positive development. [ABSTRACT FROM AUTHOR]

The complexity and spatio–temporal scale of populations' dynamics influence how populations respond to large‐scale ecological pressures. Detecting and attributing synchrony (i.e. temporally coincident fluctuations in populations' parameters) is key as synchronous populations can become more vulnerable to stochastic events that can affect the viability of harvest and have profound consequences to community structure. Here, we aimed to estimate the level of synchrony in fish growth within and among species across 1 million km2 and identify the environmental drivers contributing to synchronous population fluctuations. We developed otolith increment‐based growth chronologies for two deep‐sea scorpaenid fishes (Helicolenus dactylopterus and Pontinus kuhlii) from geographically and bathymetrically disjunct populations in the northeast Atlantic (one species in three locations; two species with different depth preferences). We used hierarchical models to partition variation in growth within and between populations attributing it to intrinsic (age, species, population) and extrinsic (environmental variables) drivers. We assessed synchrony in growth variation within and among species and identified common change points in population specific growth patterns. We documented time‐variant synchrony in growth variation of geographically and bathymetrically segregated deep‐sea fish populations, lasting 25 and 18 years, respectively. The observed synchrony was likely driven by shared environmental forcing (Moran effect) as large‐scale climate indices (East Atlantic pattern and North Atlantic Oscillation) were important environmental drivers of overall growth variation while the onset of synchrony in growth variation was likely related to marine regime shifts occurring in a wide area of the northeast Atlantic that affected the entire ecosystem. However, our capacity to extrapolate growth information across species and locations was dependent on the timing and magnitude of environmental change. Developing a better understanding of the mechanisms driving growth synchrony is key to ensure sustainable management of populations in habitats that are fragile and highly sensible to environmental change, such as the deep‐sea. [ABSTRACT FROM AUTHOR]

Increasing human population size and mobility have accelerated the translocation of nonnative species globally, which has become a major threat to conservation of biodiversity and ecosystem services. Introduced species can disrupt species interactions of the recipient ecosystem, triggering system‐wide events, and amplify or dampen effects of existing pressures. We show how two pervasive intercontinental invasive consumers in North American lakes, dreissenids (filter‐feeding mussels) and Bythotrephes (carnivorous zooplankton), nonlinearly modify consumer–resource dynamics and undermine management interventions to rebuild cold‐water predatory fish biomass. Synthesizing 30 yr (1986–2015) of lake‐wide monitoring data with a dynamic mass‐balance food‐web model (consisting of 61 species and trophic groups), we reconstructed historical food‐web dynamics of Lake Simcoe, a large, temperate lake in Ontario, Canada that has shifted from a turbid to clear‐water state. We then analyzed patterns of biomass fluctuations of three recreationally harvested, ecologically connected populations; lake trout (Salvelinus namaycush, a piscivore), lake whitefish (Coregonus clupeaformis, a benthivore), and cisco (C. artedi, a planktivore) before and after the invasions by testing hypotheses on their delayed recoveries under management interventions–predator manipulations (fishery removal and stocking) and nutrient (phosphorus) load reduction. Analyses suggest that fishery harvest primarily regulated early recovery trajectories of the piscivore and planktivore, weakening top‐down control prior to the establishment of the invasive consumers. By contrast, the benthivore biomass patterns were shaped, in part, by the invasive mussels (via diet shift), independently of management actions. Although improved water quality (with reduced hypoxia in deeper water) and, in turn, higher macrophyte production are projected to expand the predation refuge for young fish, intensified planktivory (by Bythotrephes) and herbivory (by dreissenids) have triggered shifts in community composition (from pelagic to demersal dominance). These system‐wide shifts, in turn, have substantially diminished ecosystem productivity, thereby shrinking fishery yields. Novel consumers can rewire food webs, disrupt energy flows, and suppress predator recoveries, underscoring the need to account for altered ecological reality when sustainably managing fishery resources in invaded ecosystems. [ABSTRACT FROM AUTHOR]

The Sala fire in the Västmanland County of central Sweden that burned about 14,000 ha in 2014 has been the largest fire recorded in the modern history of Sweden. To understand the long-term fire history of this area, we dendrochronologically dated fire scars on Scots pine (Pinus sylvestris L.) trees (live and deadwood) to reconstruct the fire cycle and fire occurrence in the area affected by the 2014 fire. We identified 64 fire years, using a total of 378 pine samples. The earliest reconstructed fire dated back to 1113 AD. The spatial reconstruction extended over the period of 1480–2018 AD. Lower levels of fire activity (fire cycle, FC = 43 years, with the central 90% of the distribution limited by 35 to 57 years) dominated in the earlier period (1480–1690 AD) that was followed by a strong decrease in fire activity since 1700 (FC = 403 years, with 90% of the distribution being within 149 to 7308 years), with a fire-free period between 1756 and 2014. Sala area, therefore, features the earliest known onset of fire suppression in Scandinavia. The high demand for timber during the peak in mining activities in the study area around the 1700–1800s, accompanied by passive fire suppression policies, were possibly the main drivers of the decline in fire activity. Superposed epoch analysis (SEA) did not show significant departures in the drought proxy during the ten years with the largest area burned between 1480 and1690. It is unclear whether the result is due to the relatively small area sampled or an indication that human controls of fires dominated during that period. However, significant departures during the following period with low fire activity (1700–1756), which just preceded the last fire-free period, suggested that the climate became an increasingly important driver of fire during the onset of the suppression period. We speculate that the lack of major firebreaks, the homogenization of forests, and the lack of burned areas with low fuel loads might contribute to the occurrence of the exceptionally large 2014 fire in Sala. [ABSTRACT FROM AUTHOR]

We model optimal policy when the probability of a tipping point, the welfare change due to a tipping point, and knowledge about a tipping point's trigger all depend on the policy path. Analytic results demonstrate how optimal policy depends on the ability to affect both the probability of a tipping point and also welfare in a post-threshold world. Simulations with a numerical climate-economy model show that possible tipping points in the climate system increase the optimal near-term carbon tax by up to 45% in base case speciffcations. The resulting policy paths lower peak warming by up to 0.5 C compared to a model without possible tipping points. Different types of tipping points have qualitatively different effects on policy, demonstrating the importance of explicitly modeling tipping points' effects on system dynamics. Aversion to ambiguity in the threshold's distribution can amplify or dampen the effect of tipping points on optimal policy, but in our numerical model, ambiguity aversionincreases the optimal carbon tax.

In order to understand how North Pacific (NP) marine ecosystems have varied, 120 marine biological time series for both the western (29 time series) and eastern (91 time series) NP were analyzed with a Principal Component Analysis (PCA) for the period 1965–2006. This is the first attempt to conduct a multivariate analysis for a large number of marine biological data in the western and eastern NP combined. We used Monte-Carlo simulation to evaluate confidence levels of correlations and explained variance ratio of PCA modes while accounting for auto-correlation within the analyzed time series. All first mode principal components (PC1s), which are the time coefficients of the first PCA modes, calculated for the data in the whole, western, and eastern NP exhibit a long-term trend. The PC1s were associated with an overall increase of Alaskan and Japanese/Russian salmon, and decreases of groundfish across the basin. This mode was closely related to the warming of sea-surface temperature over the NP and over the global oceans, thereby suggesting that the strongest mode of the NP marine ecosystem was already influenced by global warming. The eastern NP PC2, characterized by multi-decadal variability, was correlated positively with salmon and negatively with groundfish. On the other hand, the western NP PC2 exhibited slightly shorter timescale interdecadal variability than the eastern NP PC2 and was negatively correlated with zooplankton and two small pelagic fish time series around Japan. The eastern NP PC2 was most strongly related to the Pacific (inter-)Decadal Oscillation index, while the western NP PC2 was most closely related to the North Pacific Gyre Oscillation index. Consequently, the present analysis provides a new and unified view of climate change and marine ecosystem variations across the western and eastern NP. In particular, it is suggested that global warming has already substantially influenced the NP marine ecosystem, and that groundfish may suffer more than pelagic fish in response to future global warming.

Abstract Algal blooms in lakes and reservoirs can be considered regime shifts from a clear‐water to algae‐dominated state that often occurs abruptly. Under experimental conditions, these regime shifts have been predicted from rises in variance and autocorrelation (generic resilience indicators) of state variables monitored at a high frequency. The goal of this study was to evaluate the behavior of resilience indicators prior to a critical transition in lakes that naturally experience algal blooms. Ambient lake conditions provide several potential hurdles that could inhibit the detection of meaningful changes in resilience indicators prior to a critical transition such as stochastic nutrient loading, spatial complexity, and decreased resilience due to higher baseline nutrient concentrations. We compiled five lake‐years of high‐frequency monitoring of chlorophyll a, phycocyanin, dissolved oxygen, and pH from four hypereutrophic lakes. Despite the factors that might hinder detecting statistical indicators of changing resilience in hypereutrophic ecosystems, we found that a rise in resilience indicators did occur prior to a critical transition in three out of four possible lake‐years, with rise beginning between 5 and 33 d prior. In one lake‐year, a critical transition occurred soon after the monitoring began, preventing detection of rising variance or autocorrelation signals which are calculated using a 21‐d rolling window. These results add to the growing body of evidence that rises in resilience indicators can be detected in ecosystems prior to a regime shift if monitoring programs are properly designed to capture the dynamics; however, continued research is needed to better understand the conditions under which resilience indicators may be useful as an early warning detection tool for lake management.

We here assess long-term trends in marine primary producers in the southern North Sea (SNS) with respect to ongoing regional Earth system changes. We applied a coupled high-resolution (1.5–4.5 km) 3d-physical-biogeochemical regional Earth System model that includes an advanced phytoplankton growth model and benthic biogeochemistry to hindcast ecosystem dynamics in the period 1961–2012. We analyzed the simulation together with in situ observations. Coinciding with the decreasing nutrient level at the beginning of the 1990s, we find a surprising increase in phytoplankton in the German Bight, but not in the more offshore parts of the SNS. We explain these complex patterns by a series of factors which are lacking in many state-of-the-art coupled ecosystem models such as changed light availability and physiological acclimation in phytoplankton. We also show that many coastal time-series stations in the SNS are located in small patches where our model predicts an opposite trend than found for the surrounding waters. Together, these findings call for a reconsideration of current modeling and monitoring schemes.

Fens and bogs are distinct in terms of their biogeochemistry, water table behavior, and net peat-accumulation regimes. While most peatlands start developing as fens, a large fraction of them eventually shift to bogs in a step-like ecosystem shift. This transition has traditionally been assumed to be primarily controlled by the ecosystem itself (autogenic control). Here we use 90 peat profiles from southernmost South America (SSA) as a case study that illustrates a synchronous, regional-scale shift from fen to bog around 4200 years ago. In light of these results, we propose and discuss conceptual models that link environmental change (allogenic control) as a trigger to the fen-bog transition (FBT). In addition, our stratigraphic analyses show that Sphagnum deposits are associated with greater peat masses, larger soil-carbon stocks, and higher rates of peat-carbon accumulation than their non-Sphagnum counterparts, with Sphagnum bogs being characterized by soil-carbon densities over twice that of non-Sphagnum peatlands (medians = 141 vs. 56 kgC/m2). Since fens and bogs also behave differently in terms of their carbon exchanges with the atmosphere, a better appraisal of the processes involved in the FBT could help elucidate the role of this critical ecosystem shift in the past and future global carbon cycle.

The main seasonal characteristics in the tropics include both spatial patterns and temporal parameters of onset, cessation, duration, and the number of wet and dry seasons. Previous studies showed that wet seasons shortened and dry seasons extended with global warming, but the changes in spatial distribution and the number of wet and dry seasons are still unclear. Here, we analyze the climatic characteristics of once wet and dry season a year (annual regime) and twice wet and dry seasons a year (biannual regime), and find that regimes of wet and dry seasons have changed from 1935 to 2014. Across the equator and the Tropic of Cancer and Capricorn, some regions where there used to be an annual regime have become a biannual regime; instead, other regions have shifted from a biannual regime into an annual regime. With seasonal regimes shifting, areas of the biannual regime have expanded at a rate of 31 000 km ^2 /decade. Meanwhile, in annual regime regions, wet seasons have been shortened in 60.3% of regions, with an average of 7 d; the onset dates of wet seasons have been delayed in 64.8%, with an average of 6 d. Besides, wet seasons have become wetter in 51.1% of regions, and dry seasons have become drier in 59.9%. In biannual regime regions, the shortened wet seasons have occurred in 83.7% of regions, with an average shortening of 8 d, and precipitation has decreased in both wet and dry seasons. Moreover, the shorter wet seasons will amplify further by the end of the 21st century. The continuous seasonal changes will threaten agricultural, ecological security, and even human well-being.

Critical transitions between ecosystem states can be triggered by relatively small external forces or internal perturbations and may show time-lagged or hysteretic recovery. Understanding the precise mechanisms of a transition is important for ecosystem management, but it is hampered by a lack of information about the preceding interactions and associated feedback between different components in an ecosystem. This paper employs a range of data, including paleolimnological, environmental monitoring and documentary sources from lake Erhai and its catchment, to investigate the ecosystem structure and dynamics across multiple trophic levels through the process of eutrophication. A long-term perspective shows the growth and decline of two distinct, but coupled, positive feedback loops: a macrophyte-loop and a phosphorus-recycling-loop. The macrophyte-loop became weaker, and the phosphorus-recycling-loop became stronger during the process of lake eutrophication, indicating that the critical transition was propelled by the interaction of two positive feedback loops with different strengths. For lake restoration, future weakening of the phosphorus-recycling loop or a reduction in external pressures is expected to trigger macrophyte growth and eventually produce clear water conditions, but the speed of recovery will probably depend on the rates of feedback loops and the strength of their coupling.

Understanding changes in Antarctic ice shelf basal melting is a major challenge for predicting future sea level. Currently, warm Circumpolar Deep Water surrounding Antarctica has limited access to the Weddell Sea continental shelf; consequently, melt rates at Filchner‐Ronne Ice Shelf are low. However, large‐scale model projections suggest that changes to the Antarctic Slope Front and the coastal circulation may enhance warm inflows within this century. We use a regional high‐resolution ice shelf cavity and ocean circulation model to explore forcing changes that may trigger this regime shift. Our results suggest two necessary conditions for supporting a sustained warm inflow into the Filchner Ice Shelf cavity: (i) an extreme relaxation of the Antarctic Slope Front density gradient and (ii) substantial freshening of the dense shelf water. We also find that the on‐shelf transport over the western Weddell Sea shelf is sensitive to the Filchner Trough overflow characteristics. Plain Language Summary: The Weddell Sea continental shelf is presently filled with water masses that are too cold to melt the Filchner‐Ronne Ice Shelf from below. If warmer offshore water masses gain access to the Weddell Sea continental shelf and flow into the ice shelf cavity, the ocean‐driven melting would increase rapidly and cause ice shelf thinning. Increased ice shelf melting would supply the continental shelf with freshwater that influence sea ice production and generation of dense water masses and cause an increased discharge of grounded ice, which would contribute to global sea level rise. Two main factors currently prevent warm water from accessing the Weddell Sea continental shelf. First, the warm water is located deeper than the continental shelf and does not have direct access. Second, the Weddell Sea continental shelf is filled with dense water masses that block an inflow of warmer and lighter water. We use a regional ocean model to investigate what would happen if the warm offshore water is lifted higher up or if the dense water masses become fresher and lighter. We find that the Weddell Sea system is robust, and we need to make extreme changes to both factors to allow warm water access to the continental shelf. Key Points: Thermocline heaving and freshening of the high‐density shelf water are both needed to cause a cold‐to‐warm regime shift in the Weddell SeaThe presence of dense shelf water in Filchner Trough limits inflow of warm water toward the Filchner Ice Shelf frontReduced Filchner Trough overflow may cause increased on‐shelf transport, and thus warming, in the western Weddell Sea [ABSTRACT FROM AUTHOR]

In this paper, we consider sequential online prediction (SOP) for streaming data in the presence of outliers and change points. We propose an INstant TEmporal structure Learning (INTEL) algorithm to address this problem. Our INTEL algorithm is developed based on a full consideration of the duality between online prediction and anomaly detection. We first employ a mixture of weighted Gaussian process models (WGPs) to cover the expected possible temporal structures of the data. Then, based on the rich modeling capacity of this WGP mixture, we develop an efficient technique to instantly learn (capture) the temporal structure of the data that follows a regime shift. This instant learning is achieved only by adjusting one hyper-parameter of the mixture model. A weighted generalization of the product of experts (POE) model is used for fusing predictions yielded from multiple GP models. An outlier is declared once a real observation seriously deviates from the fused prediction. If a certain number of outliers are consecutively declared, then a change point is declared. Extensive experiments are performed using a diverse of real datasets. Results show that the proposed algorithm is significantly better than benchmark methods for SOP in the presence of outliers and change points. [ABSTRACT FROM AUTHOR]

The aim of this paper is to find economic factors that could be helpful in explaining the market's shifts between periods of prosperity and crisis. The study took into account the main stock indices from developed markets of the USA, Germany and Great Britain, and from two emerging markets, i.e. Poland and Turkey. The analysis confirms the existence of two different states of volatility in these markets, namely the state with a positive returns' mean and low volatility, and the state with a negative or insignificant mean and high volatility. The Markov-switching model with a dynamic probability matrix was applied in the study. The subject of the analysis was the impact of domestic and global factors, such as VIX and TED spread, oil prices, sentiment indices (ZEW), and macroeconomic indices (unemployment, long-term interest rate, CPI), on the probability of switching between the states. The authors concluded that in all the examined countries, changes in long-term interest rates have an influence on market returns. However, the direction of this impact is different for developed and emerging markets. As regards developed markets, high prices of oil, 10-year bonds, and the ZEW index can suggest a high probability of the countries remaining in the first state, whereas an increase in the VIX index and the TED spread significantly reduces the probability of staying in this state. The other studied factors proved to be rather local in nature. [ABSTRACT FROM AUTHOR]

Algal blooms in lakes and reservoirs can be considered regime shifts from a clear‐water to algae‐dominated state that often occurs abruptly. Under experimental conditions, these regime shifts have been predicted from rises in variance and autocorrelation (generic resilience indicators) of state variables monitored at a high frequency. The goal of this study was to evaluate the behavior of resilience indicators prior to a critical transition in lakes that naturally experience algal blooms. Ambient lake conditions provide several potential hurdles that could inhibit the detection of meaningful changes in resilience indicators prior to a critical transition such as stochastic nutrient loading, spatial complexity, and decreased resilience due to higher baseline nutrient concentrations. We compiled five lake‐years of high‐frequency monitoring of chlorophyll a, phycocyanin, dissolved oxygen, and pH from four hypereutrophic lakes. Despite the factors that might hinder detecting statistical indicators of changing resilience in hypereutrophic ecosystems, we found that a rise in resilience indicators did occur prior to a critical transition in three out of four possible lake‐years, with rise beginning between 5 and 33 d prior. In one lake‐year, a critical transition occurred soon after the monitoring began, preventing detection of rising variance or autocorrelation signals which are calculated using a 21‐d rolling window. These results add to the growing body of evidence that rises in resilience indicators can be detected in ecosystems prior to a regime shift if monitoring programs are properly designed to capture the dynamics; however, continued research is needed to better understand the conditions under which resilience indicators may be useful as an early warning detection tool for lake management. [ABSTRACT FROM AUTHOR]

Managers are increasingly being asked to integrate climate change adaptation into public land management. The literature discusses a range of adaptation approaches, including managing for resistance, resilience, and transformation; but many strategies have not yet been widely tested. This study employed in-depth interviews and scenario-based focus groups in the Upper Gunnison Basin in Colorado to learn how public land managers envision future ecosystem change, and how they plan to utilize different management approaches in the context of climate adaptation. While many managers evoked the past in thinking about projected climate impacts and potential responses, most managers in this study acknowledged and even embraced (if reluctantly) that many ecosystems will experience regime shifts in the face of climate change. However, accepting that future ecosystems will be different from past ecosystems led managers in different directions regarding how to respond and the appropriate role of management intervention. Some felt management actions should assist and even guide ecosystems toward future conditions. Others were less confident in projections and argued against transformation. Finally, some suggested that resilience could provide a middle path, allowing managers to help ecosystems adapt to change without predicting future ecosystem states. Scalar challenges and institutional constraints also influenced how managers thought about adaptation. Lack of institutional capacity was believed to constrain adaptation at larger scales. Resistance, in particular, was considered impractical at almost any scale due to institutional constraints. Managers negotiated scalar challenges and institutional constraints by nesting different approaches both spatially and temporally. [ABSTRACT FROM AUTHOR]

Temperature is an important factor in defining the habitats of marine resource species. While satellite sensors operationally measure ocean surface temperatures, we depend on in situ measurements to characterize benthic habitats. Ship‐based measurements were interpolated to develop a time series of gridded spring and fall, surface and bottom temperature fields for the US Northeast Shelf. Surface and bottom temperatures have increased over the study period (1968–2018) at rates between 0.18–0.31°C per decade and over a shorter time period (2004–2018) at rates between 0.26–1.49°C per decade. A change point analysis suggests that a warming regime began in the surface waters in 2011 centered on Georges Bank and the Nantucket Shoals; in following years, most of the Northeast Shelf had experienced a shift in surface temperature. A similar analysis of bottom temperature suggests a warming regime began in 2008 in the eastern Gulf of Maine; in following years, change points in temperature occurred further to the west in the Gulf of Maine, finally reaching the Middle Atlantic Bight by 2010. The spatial pattern in bottom water warming is consistent with well‐known oceanographic patterns that advect warming North Atlantic waters into the Gulf of Maine. The varying spatial and temporal progression of warming in the two layers suggests they were actuated by different sets of forcing factors. We then compared these trends and change points to responses of lower and higher trophic level organisms and identified a number of coincident shifts in distribution and biomass of key forage and fisheries species. [ABSTRACT FROM AUTHOR]

Social–ecological systems (SES) exhibit complex cause‐and‐effect relationships. Capturing, interpreting, and responding to signals that indicate changes in ecosystems is key for sustainable management in SES. Breaks in this signal–response chain, when feedbacks are missing, will allow change to continue until a point when abrupt ecological surprises may occur.In these situations, societies and local ecosystems can often become uncoupled. In this paper, we demonstrate how the red loop–green loop (RL–GL) concept can be used to uncover missing feedbacks and to better understand past social–ecological dynamics. Reinstating these feedbacks in order to recouple the SES may ultimately create more sustainable systems on local scales.The RL–GL concept can uncover missing feedbacks through the characterization of SES dynamics along a spectrum of human resource dependence. Drawing on diverse qualitative and quantitative data sources, we classify SES dynamics throughout the history of Jamaican coral reefs along the RL–GL spectrum. We uncover missing feedbacks in red‐loop and red‐trap scenarios from around the year 600 until now. The Jamaican coral reef SES dynamics have moved between all four dynamic states described in the RL–GL concept: green loop, green trap, red loop and red trap.We then propose mechanisms to guide the current unsustainable red traps back to more sustainable green loops, involving mechanisms of seafood trade and ecological monitoring. By gradually moving away from seafood exports, Jamaica may be able to return to green‐loop dynamics between the local society and their locally sourced seafood. We discuss the potential benefits and drawbacks of this proposed intervention and give indications of why an export ban may insure against future missing feedbacks and could prolong the sustainability of the Jamaican coral reef ecosystem.Our approach demonstrates how the RL–GL approach can uncover missing feedbacks in a coral reef SES, a way the concept has not been used before. We advocate for how the RL–GL concept in a feedback setting can be used to synthesize various types of data and to gain an understanding of past, present and future sustainability that can be applied in diverse social–ecological settings. A free Plain Language Summary can be found within the Supporting Information of this article. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

This short paper provides a modeling framework for unifying the economy, climate change and the outbreak of infectious diseases such as the recent COVID-19 pandemic. We stress that continuous growth of consumption activities, capital accumulation and climate change could increase the potential of the epidemic, its contact number or the probability of its arrival. This framework of analysis allows us to think of infectious disease policies in two stages. In the short run, containment policies like social distancing could help to stop the epidemic. In the medium and the long run, economic policies could help to reduce the potential of the epidemic or the probability of its emergence. [ABSTRACT FROM AUTHOR]

Category five hurricanes Irma and María (September 2017) caused significant damage to shallow seagrass communities across Puerto Rico. The magnitude and spatial extent of hurricane impacts on representative seagrass habitats of Culebra Island were addressed using a combination of random photo-quadrats and before–after hurricanes GIS-based imagery analyses. There was a significant loss of shallow seagrasses across all nine surveyed locations. Most of the documented impacts were associated with sediment bedload (horizontal transport), which resulted in burial and suffocation. There was also localized physical disruption of the seagrass habitat matrix across locations exposed to stronger wave action, creating major scars and exposing below-ground structure to further disintegration by future storm events. Displaced coral rubble also caused seagrass burial. Aerial imagery analyses (2007, 2010, 2017) showed a significant decline in seagrass percent cover. Seagrass decline was positively correlated with wave exposure (p < 0.05). Seagrass cover, density, and changes in benthic community structure were documented across five of the surveyed locations during 2018, and these data were further compared to data collected in 2004 at these same sites. There was a decline in percent seagrass cover and density and a change in benthic community structure favoring habitat homogenization. A remarkable finding was the rapid recovery, expansion, and increased localized dominance of the invasive seagrass, Halophila stipulacea. This was particularly evident in areas impacted by recurrent land-based runoff pulses, anchoring, sediment resuspension due to navigation, trampling or by the accumulation of decaying Sargassum mats. Hurricanes triggered a localized shift in marine vegetation, favoring the invasion of H. stipulacea, with potentially significant consequences on ecosystem resilience and on the ability of native in seagrasses to persist and adapt to projected climate change impacts. [ABSTRACT FROM AUTHOR]

Palaeoecological data are unique historical archives that extend back far beyond the last several decades of ecological observations. However, the fossil record of continental shelves has been perceived as too coarse (with centennial-millennial resolution) and incomplete to detect processes occurring at yearly or decadal scales relevant to ecology and conservation. Here, we show that the youngest (Anthropocene) fossil record on the northern Adriatic continental shelf provides decadal-scale resolution that accurately documents an abrupt ecological change affecting benthic communities during the twentieth century. The magnitude and the duration of the twentieth century shift in body size of the bivalve Corbula gibba is unprecedented given that regional populations of this species were dominated by small-size classes throughout the Holocene. The shift coincided with compositional changes in benthic assemblages, driven by an increase from approximately 25% to approximately 70% in median per-assemblage abundance of C. gibba. This regime shift increase occurred preferentially at sites that experienced at least one hypoxic event per decade in the twentieth century. Larger size and higher abundance of C. gibba probably reflect ecological release as it coincides with an increase in the frequency of seasonal hypoxia that triggered mass mortality of competitors and predators. Higher frequency of hypoxic events is coupled with a decline in the depth of intense sediment mixing by burrowing benthic organisms from several decimetres to less than 20 cm, significantly improving the stratigraphic resolution of the Anthropocene fossil record and making it possible to detect sub-centennial ecological changes on continental shelves. [ABSTRACT FROM AUTHOR]

Habitat alterations that result from anthropogenic disturbance impact both the abiotic and biotic conditions of ecosystems, causing changes in biodiversity in many parts of the world. Recently, the use of functional diversity has been suggested as an approach to better evaluate the effects of such disturbance on particular communities. Here, we investigated the temporal changes in species and functional diversities of fish communities in the downstream area of the Three Gorges Dam (TGD) before, during, and after impoundment. We found two regime shifts in the fish community in 2004 and 2013 following impoundment. Although taxonomic diversity declined sharply at the first regime shift, it increased at the second shift. On the other hand, functional diversity declined throughout the same period, indicating the loss of functional diversity despite increased species diversity. Our analysis also showed that the fish communities shifted from under‐dispersion to over‐dispersion due to both a decrease in the relative abundance of migratory fish and an increase in the number of fish adapted to the new hydrologic conditions. Our results indicated that the impacts of dams on downstream fish communities may change over time. Interactions between species may become more important when the environment is stable. [ABSTRACT FROM AUTHOR]

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The storied Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri; YCT) population of Yellowstone Lake, Yellowstone National Park, Wyoming, USA, has shown a profound and mostly continuous decline since the 1970s despite pristine habitat and vanishing angler harvests. An age-structured Leslie model that had a broad climate index as its only driver (regulating age-0 YCT survival) was Bayesian-fitted to data for a key YCT spawning stock from 1977 to 1992, arguably before predation from an introduced lake trout (Salvelinus namaycush) population (1994 discovery) measurably affected YCT population dynamics. The middle 50% of model fits encompassed 12 of 14 observed spawning populations and nominally excluded the others. Forecasting to 2007 (the final empirical data year) showed the new climate regime largely explained declining YCT numbers, but a growing predation effect became evident soon after lake trout discovery and quickly became the major YCT population driver. The climate effect may have involved the fatal blockage of out-emigrating YCT fry by natural alluvial deposits at spawning tributary mouths in warm, dry years. The previously reported Yellowstone Lake ecosystem shift suggested by the YCT population decline actually began with the 1977 North Pacific Basin climate shift and was only later enhanced by lake trout predation. This study showed identifying and accounting for the overarching population drivers is important to structuring statistical models intended to detect and assess the effects of new and emerging population impacts across historic data sets. Management actions intended to protect these YCT must consider climate effects and probable future climates. [ABSTRACT FROM AUTHOR]

Canopy‐forming algae play a key role in temperate coastal ecosystems sustaining complex habitats that provide food and refuge for rich associated biotic communities. These macroalgae are in decline in many coastal areas, where overgrazing by herbivores can lead to the loss of these highly structured and diverse habitats toward less complex sea urchin barren grounds. Once established, low productive barren grounds are considered stable states maintained by several positive feedback mechanisms that prevent the recovery of marine forests. To revert this global decline, restoration efforts and measures are being encouraged by EU regulations and local actions. Here, we tested the success of active revegetation techniques as a tool to promote functional and productive Treptacantha elegans forests in sea urchin barren grounds under different restoration strategies (active, and combined active with passive strategies). Active revegetation was performed in 6 barren grounds, 3 located inside a Mediterranean No‐Take marine reserve (active and passive strategy) and 3 outside (active strategy alone), following a three‐step protocol: (1) sea urchin population eradication, (2) seeding with Treptacantha elegans, and (3) enhancement of T. elegans recruitment. Revegetation success was assessed 1 year later in the six barren grounds, but was only achieved after combining active with passive restoration strategies. Our results encourage revegetation of barren grounds to shift from less productive habitats to complex T. elegans forests, highlight the potential of the combined passive and active restoration strategies, as well as the important role of marine reserves not only in conservation but also in ecological restoration. [ABSTRACT FROM AUTHOR]

The Indo‐Gangetic plains (IGP) in India witness widespread fog during winter months of December–January–February (DJF) since 1970s at temperatures between 5 and 20°C. Despite its vast spatial extent, the localized physical nature of fog over various time and space scales limits successful attempts of its accurate prediction. This poses a challenge towards reducing calamities and huge economic losses associated with the consequent visibility degradation. Increasing rate of urbanization and both enhanced natural and anthropogenic forcing influence fog formation, persistence, and dissipation. It is imperative to understand the associated changes in fog trends to ascertain the effect of these forcing on fog and quantify its prediction. Therefore, the trends in fog occurrence over the Indo‐Gangetic plains are assessed for a period of 37 years from 1977/1978–2013/2014 (DJF). A statistically significant increasing trend in fog frequency is found to be related to changes in associated meteorological parameters. The shift of visibility around year of 1998 is indicated by important changes occurred in temperature, humidity, and wind speed. Distinct patterns before and after 1998 are observed for fog visibility conditions and that may have significant implications for weather forecasts and local climate change. [ABSTRACT FROM AUTHOR]

Ecologists have long studied patterns, directions and tempos of change, but there is a pressing need to extend current understanding to empirical observations of abrupt changes as climate warming accelerates. Abrupt changes in ecological systems (ACES)--changes that are fast in time or fast relative to their drivers--are ubiquitous and increasing in frequency. Powerful theoretical frameworks exist, yet applications in real-world landscapes to detect, explain and anticipate ACES have lagged. We highlight five insights emerging from empirical studies of ACES across diverse ecosystems: (i) ecological systems show ACES in some dimensions but not others; (ii) climate extremes may be more important than mean climate in generating ACES; (iii) interactions among multiple drivers often produce ACES; (iv) contingencies, such as ecological memory, frequency and sequence of disturbances, and spatial context are important; and (v) tipping points are often (but not always) associated with ACES. We suggest research priorities to advance understanding of ACES in the face of climate change. Progress in understanding ACES requires strong integration of scientific approaches (theory, observations, experiments and process-based models) and high-quality empirical data drawn from a diverse array of ecosystems. [ABSTRACT FROM AUTHOR]

The loss of canopy‐forming seaweeds from urbanized coasts has intensified in response to warming seas and non‐climatic pressures such as population growth and declining water quality. Surprisingly, there has been little information on the extent of historical losses in the South‐western Atlantic, which limits our ability to place this large marine ecosystem in a global context. Here, we use meta‐analysis to examine long‐term (1969–2017) changes to the cover and biomass of Sargassum spp. and structurally simple algal turfs along more than 1,000 kilometres of Brazil's warm temperate coastline. Analysis revealed major declines in canopy cover that were independent of season (i.e., displaying similar trends for both summer and winter) but varied with coastal environmental setting, whereby sheltered bays experienced greater losses than coastal locations. On average, covers of Sargassum spp. declined by 2.6% per year, to show overall losses of 52% since records began (ranging from 20% to 89%). This contrasted with increases in the cover of filamentous turfs (24% over the last 27 years) which are known to proliferate along human‐impacted coasts. To test the relative influence of climatic versus non‐climatic factors as drivers of this apparent canopy‐to‐turf shift, we examined how well regional warming trends (decadal changes to sea surface temperature) and local proxies of coastal urbanization (population density, thermal pollution, turbidity and nutrient inputs) were able to predict the changes in seaweed communities. Our results revealed that the most pronounced canopy losses over the past 50 years were at sites exhibiting the greatest degree of coastal warming, the highest population growth and those located in semi‐enclosed sheltered bays. These findings contribute knowledge on the drivers of canopy loss in the South‐western Atlantic and join with global efforts to understand and mitigate declines of marine keystone species. [ABSTRACT FROM AUTHOR]

The distributions of ice season characteristics in the Baltic Sea during 1982-2016 were studied. A shift in the ice season regime was observed in 2006-2007. Ice season characteristics before and after the shift were determined in the northern and southern regions of the Baltic Sea, and the contributions of these areas to the shift regime were evaluated. To study changes in ice conditions, satellite data on the daily ice concentration over the Baltic Sea provided by the Copernicus Marine Environment Monitoring Service were used. The ice cover extent and number of ice days were calculated. The maximal ice extent event of the ice season shifted from the beginning of March to the end of January in 2007. The average ice concentration over the Baltic Sea was 18% and 10% before and after the shift, respectively. On average, 32 and 19 ice days occurred before and after the shift, respectively. The average ice concentration in the northern Baltic was 54% before and 34% after the shift, and the concentration in the southern Baltic was 8% before and 7% after the shift. The determined shift of the ice season characteristics indicated that extensive ice cover does not last long during the after-shift seasons. [ABSTRACT FROM AUTHOR]

Studies of small-scale, self-organized social-ecological systems have contributed to our understanding of successful governance of shared resources. However, the lack of formal analytically tractable models of such coupled infrastructure systems makes it difficult to connect this understanding to such concepts as stability, robustness, and resilience, which are increasingly important in considering such systems. In this paper, we mathematically operationalize a widely used conceptual framework via a stylized dynamical model. The model yields a wide range of system outcomes: sustainability or collapse, infrastructure at full or partial capacity, and social agents seeking outside opportunities or exclusively engaging in the system. The low dimensionality of the model enables us to derive these conditions in clear relationships of biophysical and social factors describing the coupled system. Analysis of the model further reveals regime shifts, trade-offs, and potential pitfalls that one may face in governing these selforganized systems. The intuition and insights derived from the model lay ground for more rigorous treatment of robustness and resilience of self-organized coupled infrastructure systems, which can lead to more effective governance. [ABSTRACT FROM AUTHOR]

This paper discusses the recent progress in understanding the properties of transient dynamics in complex ecological systems. Predicting long-term trends as well as sudden changes and regime shifts in ecosystems dynamics is a major issue for ecology as such changes often result in population collapse and extinctions. Analysis of population dynamics has traditionally been focused on their long-term, asymptotic behavior whilst largely disregarding the effect of transients. However, there is a growing understanding that in ecosystems the asymptotic behavior is rarely seen. A big new challenge for theoretical and empirical ecology is to understand the implications of long transients. It is believed that the identification of the corresponding mechanisms along with the knowledge of scaling laws of the transient's lifetime should substantially improve the quality of long-term forecasting and crisis anticipation. Although transient dynamics have received considerable attention in physical literature, research into ecological transients is in its infancy and systematic studies are lacking. This text aims to partially bridge this gap and facilitate further progress in quantitative analysis of long transients in ecology. By revisiting and critically examining a broad variety of mathematical models used in ecological applications as well as empirical facts, we reveal several main mechanisms leading to the emergence of long transients and hence lays the basis for a unifying theory. • Ecosystems dynamics are usually transient and the analysis of the asymptotic properties of corresponding models is not always relevant. • Transient regimes can last very long time and finish with abrupt transition to another state or regime, hence resembling a regime shift. • We identify several basic dynamical mechanisms resulting in the long transient dynamics in both nonspatial and spatial systems. • Theoretical considerations are linked to available laboratory and field observations, implications for ecosystems management are discussed. [ABSTRACT FROM AUTHOR]

The formation mechanism as well as its temporal change of the North Pacific subtropical mode water (NPSTMW) is investigated using a 50‐year (1960–2009) ocean general circulation model hindcast. The volume budget analysis suggests that the formation of the NPSTMW is mainly controlled by the air‐sea interaction and ocean dynamics, but there is a regime shift of the relative importance between the two around late‐1980s. While the local air‐sea interaction process is a main driver of the NPSTMW formation prior to late‐1980s, ocean dynamics including the vertical entrainment become dominant since then. The NPSTMW formation is affected by the North Pacific Oscillation simultaneously in the early period, but with a few years lag in the later period. The interdecadal change of the driving mechanism of the interannual variability of the NPSTMW is probably due to the stronger (weaker) influence of local atmospheric forcing in the western North Pacific and unfavorable (favorable) wind stress curl condition for the remote oceanic forcing from the central North Pacific during the former (later) period. This regime shift may be related to the change of centers of the actions of the wind stress curl since the late‐1980s. Plain Language Summary: Using a three‐dimensional ocean model, we conduct a numerical simulation for 1960–2009. The ocean model reproduces well the feature of the North Pacific subtropical mode water (NPSTMW), which is characterized by a thick subsurface layer of the relatively uniform temperature and potential density, to the east and south of Japan. During cooling seasons (from December to following March), the NPSTMW is formed by the atmospheric cooling and the oceanic processes, such as the deepening of the mixed layer depth and advective flux. Our study found that the relative contributions from the two factors differ in two different epochs, before and after late‐1980s. Before late‐1980s, the atmospheric cooling mainly controls the NPSTMW formation, while the oceanic processes driven by remote forcing significantly contribute the NPSTMW formation after late‐1980s. The variability of the NPSTMW formation is related to the basin‐scale climate variability, particularly the North Pacific Oscillation. Key Points: The air‐sea interaction primarily drives the formation of the North Pacific subtropical mode water prior to late‐1980sSince late‐1980s, the formation of the subtropical mode water is mainly controlled by the ocean dynamics driven by remote forcingThe variability of the formation rate is associated to the North Pacific Oscillation [ABSTRACT FROM AUTHOR]

Background and Aims Coastal wetlands have evolved to withstand stressful abiotic conditions through the maintenance of hydrologic feedbacks between vegetation production and flooding. However, disruption of these feedbacks can lead to ecosystem collapse, or a regime shift from vegetated wetland to open water. To prevent the loss of critical coastal wetland habitat, we must improve understanding of the abiotic–biotic linkages among flooding and wetland stability. The aim of this research was to identify characteristic landscape patterns and thresholds of wetland degradation that can be used to identify areas of vulnerability, reduce flooding threats and improve habitat quality. Methods We measured local- and landscape-scale responses of coastal wetland vegetation to flooding stress in healthy and degrading coastal wetlands. We hypothesized that conversion of Spartina patens wetlands to open water could be defined by a distinct change in landscape configuration pattern, and that this change would occur at a discrete elevation threshold. Key Results Despite similarities in total land and water cover, we observed differences in the landscape configuration of vegetated and open water pixels in healthy and degrading wetlands. Healthy wetlands were more aggregated, and degrading wetlands were more fragmented. Generally, greater aggregation was associated with higher wetland elevation and better drainage, compared with fragmented wetlands, which had lower elevation and poor drainage. The relationship between vegetation cover and elevation was non-linear, and the conversion from vegetated wetland to open water occurred beyond an elevation threshold of hydrologic stress. Conclusions The elevation threshold defined a transition zone where healthy, aggregated, wetland converted to a degrading, fragmented, wetland beyond an elevation threshold of 0.09 m [1988 North American Vertical Datum (NAVD88)] [0.27 m mean sea level (MSL)], and complete conversion to open water occurred beyond 0.03 m NAVD88 (0.21 m MSL). This work illustrates that changes in landscape configuration can be used as an indicator of wetland loss. Furthermore, in conjunction with specific elevation thresholds, these data can inform restoration and conservation planning to maximize wetland stability in anticipation of flooding threats. [ABSTRACT FROM AUTHOR]

Ecosystems can experience sudden regime shifts due to a variety of mechanisms. Two of the ways a system can cross a tipping point include when a perturbation to the system state is large enough to push the system beyond the basin of attraction of one stable state and into that of another (state tipping), and alternately, when slow changes to some underlying parameter lead to a fold bifurcation that annihilates one of the stable states. The first mechanism does not generate the phenomenon of critical slowing down (CSD), whereas the latter does generate CSD, which has been postulated as a way to detect early warning signs ahead of a sudden shift. Yet distinguishing between the two mechanisms (s-tipping and b-tipping) is not always as straightforward as it might seem. The distinction between "state" and "parameter" that may seem self-evident in mathematical equations depends fundamentally on ecological details in model formulation. This distinction is particularly relevant when considering high-dimensional models involving trophic webs of interacting species, which can only be reduced to a one-dimensional model of a tipping point under appropriate consideration of both the mathematics and biology involved. Here we illustrate that process of dimension reduction and distinguishing between s- and b-tipping for a highly influential trophic cascade model used to demonstrate tipping points and test CSD predictions in silico, and later, in a natural lake ecosystem. Our analysis resolves a previously unclear issue as to the nature of the tipping point involved. [ABSTRACT FROM AUTHOR]

While marine populations change all the time, sometimes regime shifts involve an entire ecosystem, resulting in crucial and sometimes permanent alterations in the ecosystem trophic web and services. A commonly used method to detect shifts in marine systems is the Sequential t-test Analysis of Regime Shifts (STARS). In this work, we chose to analyse the limits and performance of STARS because of its free open-source software and wide use. For the first time, we tested the STARS algorithm using synthetic time series and autoregressive integrated moving average time series, designed to resemble natural observations. We then applied the information obtained from these tests to investigate the STARS detections on an observed time series, that of Calanus finmarchicus in the North Sea. Our tests indicated that in no experiments did STARS detect 100% of the artificial change points at the exact time of the shift. In most cases, STARS tended to anticipate the shift by a few time units. Overall, we determined STARS to be a good method to detect shifts in observed natural time series, so long as the exact time of the shift is not necessary and the possibility of false positives is taken into account. [ABSTRACT FROM AUTHOR]

In diverse ecosystems, organisms cluster together in such a manner that the frequency distribution of cluster sizes is a power law function. Spatially explicit computational models of ecosystems suggest that a loss of such power law clustering may indicate a loss of ecosystem resilience; the empirical evidence in support for this hypothesis has been mixed. On the other hand, a well‐known dynamical feature of systems with reduced resilience is the slower recovery from perturbations, a phenomenon known as critical slowing down (CSD). Here, we examine the relationship between spatial clustering and CSD to better understand the use of cluster size distributions as indicators of ecosystem resilience.Local positive feedback is an important driver of spatial clustering, while also affecting the dynamics of the ecosystem: Studies have demonstrated that positive feedback promotes abrupt regime shifts. Here, we analyse a spatial model of ecosystem transitions that enables us to disentangle the roles of local positive feedback and environmental stress on spatial patterns and ecosystem resilience.We demonstrate that, depending on the strength of positive feedback, power law clustering can occur at any distance from the critical threshold of ecosystem collapse. In fact, we find that for systems with strong positive feedback, which are more likely to exhibit abrupt transitions, there may be no loss of power law clustering prior to critical thresholds.Our analyses show that cluster size distributions are unrelated to the phenomenon of CSD and that loss of power law clustering is not a generic indicator of ecosystem resilience. Further, due to CSD, a power law feature does occur near critical thresholds but in a different quantity; specifically, a power law decay of spatial covariance of ecosystem state. Our work highlights the importance of links between local positive feedback, emergent spatial properties and how they may be used to interpret ecosystem resilience. [ABSTRACT FROM AUTHOR]

Conservation efforts and sustainable use of natural populations often seek to reach or maintain viable abundance levels for a target population. Yet, this goal can be undermined by a number of events resulting from out-of-equilibrium dynamics, including large and sudden changes in abundance. The dynamical properties of such temporal changes are valuable indications about population's capacity to cope with environmental changes. Correctly identifying past or anticipating impending occurrences of temporal abrupt shifts in ecological systems is thus of major importance to adjust conservation and management strategies. Despite many available abrupt shift detection methods, few offer the possibility to compare and agree on the best model among linear, nonlinear, or abrupt models. By combining several existing methods, we develop an approach that classifies any timeseries to a trajectory type – no change, linear, nonlinear (quadratic), abrupt – and confirms the occurrence of potential abrupt shifts. We assessed the classification performances using a set of simulated data for which we had deterministic predictions for each type of trajectories. We used various levels of noise and perturbation events to make the simulations more realistic. This classification can be of particular interest when comparing dynamics of many populations across space or time. We show this by applying this classification approach to three different temporal datasets commonly used in conservation: catch tonnage, bird index, and insect occupancy timeseries. With this tool, we hope to promote conservation and management practices that explicitly take into account the likelihood of out-of-equilibrium trajectories and especially abrupt shifts in ecological systems. [ABSTRACT FROM AUTHOR]