Thorsten Blenckner - Academia.edu (original) (raw)

Papers by Thorsten Blenckner

Research paper thumbnail of Regime shifts in marine communities: a complex systems perspective on food web dynamics

Species composition and habitats are changing at unprecedented rates in the world's oceans, poten... more Species composition and habitats are changing at unprecedented rates in the world's oceans, potentially causing entire food webs to shift to structurally and functionally different regimes. Despite the severity of these regime shifts, elucidating the precise nature of their underlying processes has remained difficult. We address this challenge with a new analytic approach to detect and assess the relative strength of different driving processes in food webs. Our study draws on complexity theory, and integrates the network-centric exponential random graph modelling (ERGM) framework developed within the social sciences with community ecology. In contrast to previous research, this approach makes clear assumptions of direction of causality and accommodates a dynamic perspective on the emergence of food webs. We apply our approach to analysing food webs of the Baltic Sea before and after a previously reported regime shift. Our results show that the dominant food web processes have remained largely the same, although we detect changes in their magnitudes. The results indicate that the reported regime shift may not be a system-wide shift, but instead involve a limited number of species. Our study emphasizes the importance of community wide analysis on marine regime shifts and introduces a novel approach to examine food webs.

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Research paper thumbnail of Regime shifts in marine communities: a complex systems perspective on food web dynamics

Proceedings of the Royal Society B: Biological Sciences, 2016

Species composition and habitats are changing at unprecedented rates in the world&amp... more Species composition and habitats are changing at unprecedented rates in the world's oceans, potentially causing entire food webs to shift to structurally and functionally different regimes. Despite the severity of these regime shifts, elucidating the precise nature of their underlying processes has remained difficult. We address this challenge with a new analytic approach to detect and assess the relative strength of different driving processes in food webs. Our study draws on complexity theory, and integrates the network-centric exponential random graph modelling (ERGM) framework developed within the social sciences with community ecology. In contrast to previous research, this approach makes clear assumptions of direction of causality and accommodates a dynamic perspective on the emergence of food webs. We apply our approach to analysing food webs of the Baltic Sea before and after a previously reported regime shift. Our results show that the dominant food web processes have remained largely the same, although we detect changes in their magnitudes. The results indicate that the reported regime shift may not be a system-wide shift, but instead involve a limited number of species. Our study emphasizes the importance of community-wide analysis on marine regime shifts and introduces a novel approach to examine food webs.

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Research paper thumbnail of North Atlantic Oscillation signatures in ecosystems - a meta-analysis

Global Change Biology Pp 203 212, 2002

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Research paper thumbnail of An empirical model of the Baltic Sea reveals the importance of social dynamics for ecological regime shifts

Proceedings of the National Academy of Sciences, 2015

Regime shifts triggered by human activities and environmental changes have led to significant eco... more Regime shifts triggered by human activities and environmental changes have led to significant ecological and socioeconomic consequences in marine and terrestrial ecosystems worldwide. Ecological processes and feedbacks associated with regime shifts have received considerable attention, but human individual and collective behavior is rarely treated as an integrated component of such shifts. Here, we used generalized modeling to develop a coupled social-ecological model that integrated rich social and ecological data to investigate the role of social dynamics in the 1980s Baltic Sea cod boom and collapse. We showed that psychological, economic, and regulatory aspects of fisher decision making, in addition to ecological interactions, contributed both to the temporary persistence of the cod boom and to its subsequent collapse. These features of the social-ecological system also would have limited the effectiveness of stronger fishery regulations. Our results provide quantitative, empirical evidence that incorporating social dynamics into models of natural resources is critical for understanding how resources can be managed sustainably. We also show that generalized modeling, which is well-suited to collaborative model development and does not require detailed specification of causal relationships between system variables, can help tackle the complexities involved in creating and analyzing social-ecological models.

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Research paper thumbnail of Principles for managing marine ecosystems prone to tipping points

Ecosystem Health and Sustainability, 2015

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Research paper thumbnail of Baltic Sea management: Successes and failures

AMBIO, 2015

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Research paper thumbnail of Baltic Sea ecosystem-based management under climate change: Synthesis and future challenges

Ambio, 2015

Ecosystem-based management (EBM) has emerged as the generally agreed strategy for managing ecosys... more Ecosystem-based management (EBM) has emerged as the generally agreed strategy for managing ecosystems, with humans as integral parts of the managed system. Human activities have substantial effects on marine ecosystems, through overfishing, eutrophication, toxic pollution, habitat destruction, and climate change. It is important to advance the scientific knowledge of the cumulative, integrative, and interacting effects of these diverse activities, to support effective implementation of EBM. Based on contributions to this special issue of AMBIO, we synthesize the scientific findings into four components: pollution and legal frameworks, ecosystem processes, scale-dependent effects, and innovative tools and methods. We conclude with challenges for the future, and identify the next steps needed for successful implementation of EBM in general and specifically for the Baltic Sea.

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Research paper thumbnail of Long-term progression and drivers of coastal zoobenthos in a changing system

Marine Ecology Progress Series, 2015

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Research paper thumbnail of Environmental Impacts—Freshwater Biogeochemistry

Regional Climate Studies, 2015

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Research paper thumbnail of Environmental Impacts—Marine Ecosystems

Regional Climate Studies, 2015

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Research paper thumbnail of Circulation Processes in Lakes

Encyclopedia of Earth Sciences Series, 2012

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Research paper thumbnail of Auswirkungen des Kalkens versauerter Seen auf das Phytoplankton: Untersuchungen in einem norwegischen See

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Research paper thumbnail of Synchronous regime shifts in Baltic Sea ecosystems: Similarities and dissimilarities in response to climate, nutrients and fisheries

Synchronous regime shifts in Baltic Sea ecosystems: Similarities and dissimilarities in response ... more Synchronous regime shifts in Baltic Sea ecosystems: Similarities and dissimilarities in response to climate, nutrients and fisheries Thorsten. Blenckner1, Rabea. Diekmann2, Christian. Möllmann2, Anna. Gårdmark3, Michele. Casini4, Lena Bergström3, Juha Flinkman5, ...

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Research paper thumbnail of Långtidsutvärdering Av Det Gemensamma Miljökontrollprogrammet För Fiskodlingarna På Åland 1993-2003

regeringen.ax

Beräkning av omgivningsbeskrivande parametrar....................................................... more Beräkning av omgivningsbeskrivande parametrar........................................................ 5 Analys av jämförbara data............................................................................................ 5 Utvärdering av resultat ....................................... ... ... Bilaga 4. Kontroll-och referenspunkter med jämförbar ...

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Research paper thumbnail of Aquatic Sciences A Swedish case study of contemporary and possible future consequences of climate change on lake function

A physical lake model was employed to obtain a basis of discussing the impact of climate variabil... more A physical lake model was employed to obtain a basis of discussing the impact of climate variability and climate change on the ecology of Lake Erken, Sweden. The validity of this approach was tested by running the PROBE-lake model for a 30-year period (STD) with observed meteorological data. The lake is adequately modelled, as seen in the comparison with actual lake ob­ servations. The validated lake model was then forced with meteorological data obtained from a regional clim­ ate model (RCM) with a horizontal resolution of 44 km for present (CLTR) and 2 x CO, (SCEN) climate condi­ tions. The CLTR lake simulation compares reasonably with the STD. Applying the SCEN simulation leads to a climate change scenario for the lake. The physical changes include elevated temperatures, shorter periods of ice cover combined with two of ten years being totally ice-free, and changes in the mixing regime. The ecolog­ ical consequences of the physical simulation results are derived from the historic...

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Research paper thumbnail of Regime Shifts in Marine and Lake Ecosystems: Teleconnection Patterns

Climatically induced regime shifts in aquatic ecosystems can reorganize plankton communities and ... more Climatically induced regime shifts in aquatic ecosystems can reorganize plankton communities and thus alter structural and functional system properties. These changes may be synchronized over large spatial scales and across different types of aquatic ecosystems. We studied the timing and type of long-term changes for several indicators of abiotic and biotic system components. The synchrony of regime shifts was analyzed with regard to system type (marine, freshwater), season (spring, summer) and geographic location. We choose two marine systems (North Sea, Baltic Sea) and two lakes (Müggelsee, Lake Washington). We hypothesize coherent shifts of all physical system components in spring during the late 1980s in Europe – possibly synchronized by NAO dynamics-regardless of system type and location, but out of phase with the North American system. Further, biological responses were expected to be less coherent but still obvious shifts in ecosystems. In contrast, responses of all system co...

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Research paper thumbnail of Modeling the Effects of Climate Change on the Seasonal Dynamics of Phytoplankton

The Impact of Climate Change on European Lakes, 2009

... between the control and future simulations are the predicted reductions in the early summer b... more ... between the control and future simulations are the predicted reductions in the early summer biomass of ... 15.3.4 Case Study 4: The Increased Incidence of Cyanobacterial Blooms in Galten ... the potential effects of changes in the climate on the growth of cyanobacteria in the most ...

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Research paper thumbnail of Advancing ideas, methods in interdisciplinary climate change research for New Ph.D.s

Eos, Transactions American Geophysical Union, 2003

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Research paper thumbnail of Lake Ice Phenology

The Impact of Climate Change on European Lakes, 2009

In Chapter 5 of this book, it is shown that the formation of ice on the surface of a lake (‘ice-o... more In Chapter 5 of this book, it is shown that the formation of ice on the surface of a lake (‘ice-on’) and its thawing and ultimate disappearance (‘ice-off’) are complex phenomena governed by mechanisms that involve many interacting meteorological (and some non-meteorological) forcing factors. Linking ice phenology – the timing of ice-on and ice-off – to climatic forcing might therefore

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Research paper thumbnail of Past and future challenges in managing European seas

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Research paper thumbnail of Regime shifts in marine communities: a complex systems perspective on food web dynamics

Species composition and habitats are changing at unprecedented rates in the world's oceans, poten... more Species composition and habitats are changing at unprecedented rates in the world's oceans, potentially causing entire food webs to shift to structurally and functionally different regimes. Despite the severity of these regime shifts, elucidating the precise nature of their underlying processes has remained difficult. We address this challenge with a new analytic approach to detect and assess the relative strength of different driving processes in food webs. Our study draws on complexity theory, and integrates the network-centric exponential random graph modelling (ERGM) framework developed within the social sciences with community ecology. In contrast to previous research, this approach makes clear assumptions of direction of causality and accommodates a dynamic perspective on the emergence of food webs. We apply our approach to analysing food webs of the Baltic Sea before and after a previously reported regime shift. Our results show that the dominant food web processes have remained largely the same, although we detect changes in their magnitudes. The results indicate that the reported regime shift may not be a system-wide shift, but instead involve a limited number of species. Our study emphasizes the importance of community wide analysis on marine regime shifts and introduces a novel approach to examine food webs.

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Research paper thumbnail of Regime shifts in marine communities: a complex systems perspective on food web dynamics

Proceedings of the Royal Society B: Biological Sciences, 2016

Species composition and habitats are changing at unprecedented rates in the world&amp... more Species composition and habitats are changing at unprecedented rates in the world's oceans, potentially causing entire food webs to shift to structurally and functionally different regimes. Despite the severity of these regime shifts, elucidating the precise nature of their underlying processes has remained difficult. We address this challenge with a new analytic approach to detect and assess the relative strength of different driving processes in food webs. Our study draws on complexity theory, and integrates the network-centric exponential random graph modelling (ERGM) framework developed within the social sciences with community ecology. In contrast to previous research, this approach makes clear assumptions of direction of causality and accommodates a dynamic perspective on the emergence of food webs. We apply our approach to analysing food webs of the Baltic Sea before and after a previously reported regime shift. Our results show that the dominant food web processes have remained largely the same, although we detect changes in their magnitudes. The results indicate that the reported regime shift may not be a system-wide shift, but instead involve a limited number of species. Our study emphasizes the importance of community-wide analysis on marine regime shifts and introduces a novel approach to examine food webs.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of North Atlantic Oscillation signatures in ecosystems - a meta-analysis

Global Change Biology Pp 203 212, 2002

Bookmarks Related papers MentionsView impact

Research paper thumbnail of An empirical model of the Baltic Sea reveals the importance of social dynamics for ecological regime shifts

Proceedings of the National Academy of Sciences, 2015

Regime shifts triggered by human activities and environmental changes have led to significant eco... more Regime shifts triggered by human activities and environmental changes have led to significant ecological and socioeconomic consequences in marine and terrestrial ecosystems worldwide. Ecological processes and feedbacks associated with regime shifts have received considerable attention, but human individual and collective behavior is rarely treated as an integrated component of such shifts. Here, we used generalized modeling to develop a coupled social-ecological model that integrated rich social and ecological data to investigate the role of social dynamics in the 1980s Baltic Sea cod boom and collapse. We showed that psychological, economic, and regulatory aspects of fisher decision making, in addition to ecological interactions, contributed both to the temporary persistence of the cod boom and to its subsequent collapse. These features of the social-ecological system also would have limited the effectiveness of stronger fishery regulations. Our results provide quantitative, empirical evidence that incorporating social dynamics into models of natural resources is critical for understanding how resources can be managed sustainably. We also show that generalized modeling, which is well-suited to collaborative model development and does not require detailed specification of causal relationships between system variables, can help tackle the complexities involved in creating and analyzing social-ecological models.

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Research paper thumbnail of Principles for managing marine ecosystems prone to tipping points

Ecosystem Health and Sustainability, 2015

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Baltic Sea management: Successes and failures

AMBIO, 2015

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Baltic Sea ecosystem-based management under climate change: Synthesis and future challenges

Ambio, 2015

Ecosystem-based management (EBM) has emerged as the generally agreed strategy for managing ecosys... more Ecosystem-based management (EBM) has emerged as the generally agreed strategy for managing ecosystems, with humans as integral parts of the managed system. Human activities have substantial effects on marine ecosystems, through overfishing, eutrophication, toxic pollution, habitat destruction, and climate change. It is important to advance the scientific knowledge of the cumulative, integrative, and interacting effects of these diverse activities, to support effective implementation of EBM. Based on contributions to this special issue of AMBIO, we synthesize the scientific findings into four components: pollution and legal frameworks, ecosystem processes, scale-dependent effects, and innovative tools and methods. We conclude with challenges for the future, and identify the next steps needed for successful implementation of EBM in general and specifically for the Baltic Sea.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Long-term progression and drivers of coastal zoobenthos in a changing system

Marine Ecology Progress Series, 2015

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Environmental Impacts—Freshwater Biogeochemistry

Regional Climate Studies, 2015

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Environmental Impacts—Marine Ecosystems

Regional Climate Studies, 2015

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Circulation Processes in Lakes

Encyclopedia of Earth Sciences Series, 2012

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Auswirkungen des Kalkens versauerter Seen auf das Phytoplankton: Untersuchungen in einem norwegischen See

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Synchronous regime shifts in Baltic Sea ecosystems: Similarities and dissimilarities in response to climate, nutrients and fisheries

Synchronous regime shifts in Baltic Sea ecosystems: Similarities and dissimilarities in response ... more Synchronous regime shifts in Baltic Sea ecosystems: Similarities and dissimilarities in response to climate, nutrients and fisheries Thorsten. Blenckner1, Rabea. Diekmann2, Christian. Möllmann2, Anna. Gårdmark3, Michele. Casini4, Lena Bergström3, Juha Flinkman5, ...

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Research paper thumbnail of Långtidsutvärdering Av Det Gemensamma Miljökontrollprogrammet För Fiskodlingarna På Åland 1993-2003

regeringen.ax

Beräkning av omgivningsbeskrivande parametrar....................................................... more Beräkning av omgivningsbeskrivande parametrar........................................................ 5 Analys av jämförbara data............................................................................................ 5 Utvärdering av resultat ....................................... ... ... Bilaga 4. Kontroll-och referenspunkter med jämförbar ...

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Research paper thumbnail of Aquatic Sciences A Swedish case study of contemporary and possible future consequences of climate change on lake function

A physical lake model was employed to obtain a basis of discussing the impact of climate variabil... more A physical lake model was employed to obtain a basis of discussing the impact of climate variability and climate change on the ecology of Lake Erken, Sweden. The validity of this approach was tested by running the PROBE-lake model for a 30-year period (STD) with observed meteorological data. The lake is adequately modelled, as seen in the comparison with actual lake ob­ servations. The validated lake model was then forced with meteorological data obtained from a regional clim­ ate model (RCM) with a horizontal resolution of 44 km for present (CLTR) and 2 x CO, (SCEN) climate condi­ tions. The CLTR lake simulation compares reasonably with the STD. Applying the SCEN simulation leads to a climate change scenario for the lake. The physical changes include elevated temperatures, shorter periods of ice cover combined with two of ten years being totally ice-free, and changes in the mixing regime. The ecolog­ ical consequences of the physical simulation results are derived from the historic...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Regime Shifts in Marine and Lake Ecosystems: Teleconnection Patterns

Climatically induced regime shifts in aquatic ecosystems can reorganize plankton communities and ... more Climatically induced regime shifts in aquatic ecosystems can reorganize plankton communities and thus alter structural and functional system properties. These changes may be synchronized over large spatial scales and across different types of aquatic ecosystems. We studied the timing and type of long-term changes for several indicators of abiotic and biotic system components. The synchrony of regime shifts was analyzed with regard to system type (marine, freshwater), season (spring, summer) and geographic location. We choose two marine systems (North Sea, Baltic Sea) and two lakes (Müggelsee, Lake Washington). We hypothesize coherent shifts of all physical system components in spring during the late 1980s in Europe – possibly synchronized by NAO dynamics-regardless of system type and location, but out of phase with the North American system. Further, biological responses were expected to be less coherent but still obvious shifts in ecosystems. In contrast, responses of all system co...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Modeling the Effects of Climate Change on the Seasonal Dynamics of Phytoplankton

The Impact of Climate Change on European Lakes, 2009

... between the control and future simulations are the predicted reductions in the early summer b... more ... between the control and future simulations are the predicted reductions in the early summer biomass of ... 15.3.4 Case Study 4: The Increased Incidence of Cyanobacterial Blooms in Galten ... the potential effects of changes in the climate on the growth of cyanobacteria in the most ...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Advancing ideas, methods in interdisciplinary climate change research for New Ph.D.s

Eos, Transactions American Geophysical Union, 2003

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Lake Ice Phenology

The Impact of Climate Change on European Lakes, 2009

In Chapter 5 of this book, it is shown that the formation of ice on the surface of a lake (‘ice-o... more In Chapter 5 of this book, it is shown that the formation of ice on the surface of a lake (‘ice-on’) and its thawing and ultimate disappearance (‘ice-off’) are complex phenomena governed by mechanisms that involve many interacting meteorological (and some non-meteorological) forcing factors. Linking ice phenology – the timing of ice-on and ice-off – to climatic forcing might therefore

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Past and future challenges in managing European seas

Bookmarks Related papers MentionsView impact