Numerical models of ecological systems are increasingly used by scientists to address complex env... more Numerical models of ecological systems are increasingly used by scientists to address complex environmental questions. One challenge for scientists, managers, and stakeholders is to appraise the performance of these models to answer specific questions of scientific or societal relevance, that is to perform, communicate or access transparent evaluations of ecological models. While there have been substantial developments to support standardised descriptions of ecological models, less has been done to standardise and to report model evaluation practices. We present here a general protocol designed to guide the reporting of model evaluation. The protocol is organised in three major parts: the <em>objective(s)</em> of the modelling application, the ecological <em>patterns</em> of relevance and the <em>evaluation</em> methodology proper, and is termed the OPE (objectives, patterns, evaluation) protocol. We present the 25 questions of the OPE protocol which address the many aspects of the evaluation process and then apply them to six case studies based on a diversity of ecological models. In addition to standardising and increasing the transparency of the model evaluation process, we find that going through the OPE protocol helps modellers to think more deeply about the evaluation of their models. From this last point, we suggest that it would be highly beneficial for modellers to consider the OPE early in the modelling process, in addition to using it as a reporting tool and as a reviewing tool.
The Nansen Legacy workshop on best practices for ecological model evaluation, chaired by Benjamin... more The Nansen Legacy workshop on best practices for ecological model evaluation, chaired by Benjamin Planque (IMR) was held in Tromsø on the 6-7th November 2018. The objective of the workshop was to develop recommendations for best practice in evaluation of the performance of food-web simulation models (deliverable 4-4.1.1 of the Nansen Legacy project).
Human activity has been shown to influence how animals assess the risk of predation, but we know ... more Human activity has been shown to influence how animals assess the risk of predation, but we know little about the spatial scale of such impacts. We quantified how vigilance and flight behavior in mule deer Odocoileus hemionus varied with distance from an area of concentrated human activity—a subalpine field station. An observer walked trails at various distances away from the station looking for deer. Upon encounter, the observer walked toward the focal animal and noted the distance at which it alerted and directed its attention to the approaching human (Alert Distance; AD), and the distance at which it fled (Flight Initiation Distance; FID). AD and FID both increased nonlinearly with distance from the center of the field station, reaching plateaus around 250 m and 750 m, respectively. Deer also tended to flee by stotting or running, rather than by walking, when far from the station but they walked away when near the station. These results indicate that deer perceive lower risk near...
Background/Question/Methods Behavioral ecologists quantify anti-predator behavior via measurement... more Background/Question/Methods Behavioral ecologists quantify anti-predator behavior via measurement of flight initiation distance (FID), the distance at which an animal moves away from an approaching threat. Current theory uses cost-benefit analysis to evaluate the many factors that influence escape behavior; however, the factors determining the economic decision differ among species. The goal of this study was to determine the geographic, social and anthropogenic factors that influence mule deer (Odocoileus hemionus) flight behavior around the Rocky Mountain Biological Laboratory in Gothic, CO. Mule deer at this site are important primary consumers. As such, their browsing patterns, in part determined by predator-prey relationships, have important consequences for the ecosystem. Focal individuals were observed in July and August, during dawn and dusk when deer are most active. An observer approached the focal individual at a measured pace of 1m/sec, noting Alert Distance, the distanc...
We study Marangoni patterns that emerge when common food dye is dropped into a dish of shallow wa... more We study Marangoni patterns that emerge when common food dye is dropped into a dish of shallow water. These patterns consist of tendrils and spots that sharpen over time before eventually fading. We demonstrate that the patterns can be modeled using coupled reaction-diffusion equations, where the "reaction" terms appear due to a nonlinear dependence of surface tension on dye concentration. We show using a spatio-temporal metric that these patterns are distinct from previously described Turing patterns.
ABSTRACT Background/Question/Methods The nature and extent of land-use and land-cover change (LUL... more ABSTRACT Background/Question/Methods The nature and extent of land-use and land-cover change (LULCC) in New England is influenced by large-scale economic, social, and policy conditions which are difficult to predict but that can be bracketed by scenarios describing a range of plausible future land-use conditions. Through engagement of key decision makers from state and federal agencies, and representatives from conservation organizations, academic institutions, and landowner organizations we develop a set of scenarios of future land use in Massachusetts over 50 years (2005-2055) varying from a “free market future” – with large and unregulated forest conversion - to a green future – with extensive conservation easements and clustered forest conversion. These scenarios are then used to parameterize a coupled forest succession and land use change model (PnET/Landis II) with established IPCC climate change projections to estimate landscapes at a high spatial (50m) and temporal (5yr) resolution. Modeled landscapes are used to address the principal research question of: how do projected changes alter a broad suite of ecosystem services at the scale of the state, and for individual towns and watersheds, including carbon storage, water regulation, nutrient retention, and ecosystem fragmentation and degradation, employing both analysis of Landis outputs and the InVEST approach. Results/Conclusions Results highlight the variability of future landscape changes, with simple extrapolation of current trends resulting in an increase in aboveground biomass (AGB) from ~125 to 150 Tg, primarily related to extensive carbon sequestration by aging secondary forests currently dominating the landscape. The conversion of forest to crops and pasture within the “regional self-sufficiency scenario”, however, results in a reduction of AGB from ~125 to ~120 Tg. Forest degradation – using year 2005 forests as a baseline – increases up to 250% in some scenarios over the study period. Dramatic increases in water yield are also observed across all scenarios as forest conversion alters the balance of evapotranspiration and precipitation, and climate change results in large increases in precipitation. This study both develops a novel framework for integrating and quantifying future changes in ecosystem services from coupled land use and climate change, and applies them to a study area at a pivotal transition between different future trajectories. The implications and utility of this approach to other landscapes are also discussed.
The Nansen Legacy Joint Cruise 2, part 1 (JC2-1) 12-29 July 2021, continued the investigation of ... more The Nansen Legacy Joint Cruise 2, part 1 (JC2-1) 12-29 July 2021, continued the investigation of the interannual variability during the late summer season. At the same time will the cruise provide a late summer reference for the seasonal investigation that was separated to late summer and polar night 2019, and winter and spring 2021. The transect represents an environmental gradient going through the northern Barents Sea, and included 7 process stations (P1-P7) lasting 10-39 hrs. Additional CTD stations (NLEG) were taken between the process stations to increase the hydrographic resolution on the transect. The work started at 76°N at the open Atlantic Water dominated station P1, was sea ice covered from station P4 at 79 45.00 °N and included deep water stations at the P7 station at 82°N in the Nansen Basin. The program included measurements and sampling from the atmosphere, sea ice, ocean and sea floor. Data collected includes several disciplines to map the physical environment, th...
Declining biodiversity and ecosystem functions put many of nature’s contributions to people at ri... more Declining biodiversity and ecosystem functions put many of nature’s contributions to people at risk. We review and synthesize the scientific literature to assess 50-y global trends across a broad range of nature’s contributions. We distinguish among trends in potential and realized contributions of nature, as well as environmental conditions and the impacts of changes in nature on human quality of life. We find declining trends in the potential for nature to contribute in the majority of material, nonmaterial, and regulating contributions assessed. However, while the realized production of regulating contributions has decreased, realized production of agricultural and many material commodities has increased. Environmental declines negatively affect quality of life, but social adaptation and the availability of substitutes partially offset this decline for some of nature’s contributions. Adaptation and substitutes, however, are often imperfect and come at some cost. For many of the c...
Research team final presentation at the Complex Systems Summer School 2016, Santa Fe Institute, S... more Research team final presentation at the Complex Systems Summer School 2016, Santa Fe Institute, Santa Fe, New Mexico – USA, 7th July 2016. The paper will be presented also at the Satellite Conference “Complexity History. Complexity for History and History for Complexity” of the Complex Systems Conference 2016, Amsterdam, 20th September 2016.
Globalization is a phenomenon lasting centuries. Contributing factors, including the import and export dynamics of major nations, are many in number and complex in their interactions. This study considers the behavior of one of the worlds 10 largest ports - Trieste - within the Austria-Hungarian empire from the mid 19th century through to the start of World War I (WWI), a time of profound globalization.
Trade in the mid 19th century largely followed the British World System; a free world market centered in London and its financial web. However this system was unstable, experiencing a long depression (1873-96), state defaults, and regular financial panics. Challenges from competitors, especially Germany, soon followed, and by the end of the 19th century the trade landscape had shifted, and a new nationalist era ushered in. New boarders appeared, trade restrictions were imposed, and strong cartels limited competition, within the multinational Austro-Hungarian Empire as well. The European powers competed for African resources and parted the continent. This age culminated into a denser cluster of wars and deeper crisis, from WWI to the close of WWII in 1945.
To understand how trade dynamics might evidence and interact with these various processes, information measures - including Shannon entropy and KL-divergence - were calculated on the distribution of imported and exported tonnages by nation over time and on the balance sheets of the Generali insurance company, the largest Austro-Hungarian insurer, from 1851 to 1910.
The next phase of the project will include more detailed analysis, involving data on goods per country and Generali's marine insurance contracts.
Bulletin of the American Physical Society, Nov 22, 2010
We study Marangoni patterns that emerge when common food dye is dropped into a dish of shallow wa... more We study Marangoni patterns that emerge when common food dye is dropped into a dish of shallow water. These patterns consist of tendrils and spots that sharpen over time before eventually fading. We demonstrate that the patterns can be modeled using coupled reaction-diffusion equations, where the``reaction''terms appear due to a nonlinear dependence of surface tension on dye concentration. We show using a spatio-temporal metric that these patterns are distinct from previously described Turing patterns.
In 1855, Lord Kelvin's brother, James Thomson, wrote a paper describing “certain curious mot... more In 1855, Lord Kelvin's brother, James Thomson, wrote a paper describing “certain curious motions” on liquid surfaces. In the present paper, we describe several curious motions produced in the simplest possible manner: by introducing a droplet of food coloring into a shallow dish of water. These motions include the spontaneous formation of labyrinthine stripes, the periodic pulsation leading to chaotic stretching and folding, and the formation of migrating slugs of coloring. We use this simple experiment to demonstrate that the ...
Numerical models of ecological systems are increasingly used by scientists to address complex env... more Numerical models of ecological systems are increasingly used by scientists to address complex environmental questions. One challenge for scientists, managers, and stakeholders is to appraise the performance of these models to answer specific questions of scientific or societal relevance, that is to perform, communicate or access transparent evaluations of ecological models. While there have been substantial developments to support standardised descriptions of ecological models, less has been done to standardise and to report model evaluation practices. We present here a general protocol designed to guide the reporting of model evaluation. The protocol is organised in three major parts: the <em>objective(s)</em> of the modelling application, the ecological <em>patterns</em> of relevance and the <em>evaluation</em> methodology proper, and is termed the OPE (objectives, patterns, evaluation) protocol. We present the 25 questions of the OPE protocol which address the many aspects of the evaluation process and then apply them to six case studies based on a diversity of ecological models. In addition to standardising and increasing the transparency of the model evaluation process, we find that going through the OPE protocol helps modellers to think more deeply about the evaluation of their models. From this last point, we suggest that it would be highly beneficial for modellers to consider the OPE early in the modelling process, in addition to using it as a reporting tool and as a reviewing tool.
The Nansen Legacy workshop on best practices for ecological model evaluation, chaired by Benjamin... more The Nansen Legacy workshop on best practices for ecological model evaluation, chaired by Benjamin Planque (IMR) was held in Tromsø on the 6-7th November 2018. The objective of the workshop was to develop recommendations for best practice in evaluation of the performance of food-web simulation models (deliverable 4-4.1.1 of the Nansen Legacy project).
Human activity has been shown to influence how animals assess the risk of predation, but we know ... more Human activity has been shown to influence how animals assess the risk of predation, but we know little about the spatial scale of such impacts. We quantified how vigilance and flight behavior in mule deer Odocoileus hemionus varied with distance from an area of concentrated human activity—a subalpine field station. An observer walked trails at various distances away from the station looking for deer. Upon encounter, the observer walked toward the focal animal and noted the distance at which it alerted and directed its attention to the approaching human (Alert Distance; AD), and the distance at which it fled (Flight Initiation Distance; FID). AD and FID both increased nonlinearly with distance from the center of the field station, reaching plateaus around 250 m and 750 m, respectively. Deer also tended to flee by stotting or running, rather than by walking, when far from the station but they walked away when near the station. These results indicate that deer perceive lower risk near...
Background/Question/Methods Behavioral ecologists quantify anti-predator behavior via measurement... more Background/Question/Methods Behavioral ecologists quantify anti-predator behavior via measurement of flight initiation distance (FID), the distance at which an animal moves away from an approaching threat. Current theory uses cost-benefit analysis to evaluate the many factors that influence escape behavior; however, the factors determining the economic decision differ among species. The goal of this study was to determine the geographic, social and anthropogenic factors that influence mule deer (Odocoileus hemionus) flight behavior around the Rocky Mountain Biological Laboratory in Gothic, CO. Mule deer at this site are important primary consumers. As such, their browsing patterns, in part determined by predator-prey relationships, have important consequences for the ecosystem. Focal individuals were observed in July and August, during dawn and dusk when deer are most active. An observer approached the focal individual at a measured pace of 1m/sec, noting Alert Distance, the distanc...
We study Marangoni patterns that emerge when common food dye is dropped into a dish of shallow wa... more We study Marangoni patterns that emerge when common food dye is dropped into a dish of shallow water. These patterns consist of tendrils and spots that sharpen over time before eventually fading. We demonstrate that the patterns can be modeled using coupled reaction-diffusion equations, where the "reaction" terms appear due to a nonlinear dependence of surface tension on dye concentration. We show using a spatio-temporal metric that these patterns are distinct from previously described Turing patterns.
ABSTRACT Background/Question/Methods The nature and extent of land-use and land-cover change (LUL... more ABSTRACT Background/Question/Methods The nature and extent of land-use and land-cover change (LULCC) in New England is influenced by large-scale economic, social, and policy conditions which are difficult to predict but that can be bracketed by scenarios describing a range of plausible future land-use conditions. Through engagement of key decision makers from state and federal agencies, and representatives from conservation organizations, academic institutions, and landowner organizations we develop a set of scenarios of future land use in Massachusetts over 50 years (2005-2055) varying from a “free market future” – with large and unregulated forest conversion - to a green future – with extensive conservation easements and clustered forest conversion. These scenarios are then used to parameterize a coupled forest succession and land use change model (PnET/Landis II) with established IPCC climate change projections to estimate landscapes at a high spatial (50m) and temporal (5yr) resolution. Modeled landscapes are used to address the principal research question of: how do projected changes alter a broad suite of ecosystem services at the scale of the state, and for individual towns and watersheds, including carbon storage, water regulation, nutrient retention, and ecosystem fragmentation and degradation, employing both analysis of Landis outputs and the InVEST approach. Results/Conclusions Results highlight the variability of future landscape changes, with simple extrapolation of current trends resulting in an increase in aboveground biomass (AGB) from ~125 to 150 Tg, primarily related to extensive carbon sequestration by aging secondary forests currently dominating the landscape. The conversion of forest to crops and pasture within the “regional self-sufficiency scenario”, however, results in a reduction of AGB from ~125 to ~120 Tg. Forest degradation – using year 2005 forests as a baseline – increases up to 250% in some scenarios over the study period. Dramatic increases in water yield are also observed across all scenarios as forest conversion alters the balance of evapotranspiration and precipitation, and climate change results in large increases in precipitation. This study both develops a novel framework for integrating and quantifying future changes in ecosystem services from coupled land use and climate change, and applies them to a study area at a pivotal transition between different future trajectories. The implications and utility of this approach to other landscapes are also discussed.
The Nansen Legacy Joint Cruise 2, part 1 (JC2-1) 12-29 July 2021, continued the investigation of ... more The Nansen Legacy Joint Cruise 2, part 1 (JC2-1) 12-29 July 2021, continued the investigation of the interannual variability during the late summer season. At the same time will the cruise provide a late summer reference for the seasonal investigation that was separated to late summer and polar night 2019, and winter and spring 2021. The transect represents an environmental gradient going through the northern Barents Sea, and included 7 process stations (P1-P7) lasting 10-39 hrs. Additional CTD stations (NLEG) were taken between the process stations to increase the hydrographic resolution on the transect. The work started at 76°N at the open Atlantic Water dominated station P1, was sea ice covered from station P4 at 79 45.00 °N and included deep water stations at the P7 station at 82°N in the Nansen Basin. The program included measurements and sampling from the atmosphere, sea ice, ocean and sea floor. Data collected includes several disciplines to map the physical environment, th...
Declining biodiversity and ecosystem functions put many of nature’s contributions to people at ri... more Declining biodiversity and ecosystem functions put many of nature’s contributions to people at risk. We review and synthesize the scientific literature to assess 50-y global trends across a broad range of nature’s contributions. We distinguish among trends in potential and realized contributions of nature, as well as environmental conditions and the impacts of changes in nature on human quality of life. We find declining trends in the potential for nature to contribute in the majority of material, nonmaterial, and regulating contributions assessed. However, while the realized production of regulating contributions has decreased, realized production of agricultural and many material commodities has increased. Environmental declines negatively affect quality of life, but social adaptation and the availability of substitutes partially offset this decline for some of nature’s contributions. Adaptation and substitutes, however, are often imperfect and come at some cost. For many of the c...
Research team final presentation at the Complex Systems Summer School 2016, Santa Fe Institute, S... more Research team final presentation at the Complex Systems Summer School 2016, Santa Fe Institute, Santa Fe, New Mexico – USA, 7th July 2016. The paper will be presented also at the Satellite Conference “Complexity History. Complexity for History and History for Complexity” of the Complex Systems Conference 2016, Amsterdam, 20th September 2016.
Globalization is a phenomenon lasting centuries. Contributing factors, including the import and export dynamics of major nations, are many in number and complex in their interactions. This study considers the behavior of one of the worlds 10 largest ports - Trieste - within the Austria-Hungarian empire from the mid 19th century through to the start of World War I (WWI), a time of profound globalization.
Trade in the mid 19th century largely followed the British World System; a free world market centered in London and its financial web. However this system was unstable, experiencing a long depression (1873-96), state defaults, and regular financial panics. Challenges from competitors, especially Germany, soon followed, and by the end of the 19th century the trade landscape had shifted, and a new nationalist era ushered in. New boarders appeared, trade restrictions were imposed, and strong cartels limited competition, within the multinational Austro-Hungarian Empire as well. The European powers competed for African resources and parted the continent. This age culminated into a denser cluster of wars and deeper crisis, from WWI to the close of WWII in 1945.
To understand how trade dynamics might evidence and interact with these various processes, information measures - including Shannon entropy and KL-divergence - were calculated on the distribution of imported and exported tonnages by nation over time and on the balance sheets of the Generali insurance company, the largest Austro-Hungarian insurer, from 1851 to 1910.
The next phase of the project will include more detailed analysis, involving data on goods per country and Generali's marine insurance contracts.
Bulletin of the American Physical Society, Nov 22, 2010
We study Marangoni patterns that emerge when common food dye is dropped into a dish of shallow wa... more We study Marangoni patterns that emerge when common food dye is dropped into a dish of shallow water. These patterns consist of tendrils and spots that sharpen over time before eventually fading. We demonstrate that the patterns can be modeled using coupled reaction-diffusion equations, where the``reaction''terms appear due to a nonlinear dependence of surface tension on dye concentration. We show using a spatio-temporal metric that these patterns are distinct from previously described Turing patterns.
In 1855, Lord Kelvin's brother, James Thomson, wrote a paper describing “certain curious mot... more In 1855, Lord Kelvin's brother, James Thomson, wrote a paper describing “certain curious motions” on liquid surfaces. In the present paper, we describe several curious motions produced in the simplest possible manner: by introducing a droplet of food coloring into a shallow dish of water. These motions include the spontaneous formation of labyrinthine stripes, the periodic pulsation leading to chaotic stretching and folding, and the formation of migrating slugs of coloring. We use this simple experiment to demonstrate that the ...
Uploads
Papers by Evelyn Strombom
Globalization is a phenomenon lasting centuries. Contributing factors, including the import and export dynamics of major nations, are many in number and complex in their interactions. This study considers the behavior of one of the worlds 10 largest ports - Trieste - within the Austria-Hungarian empire from the mid 19th century through to the start of World War I (WWI), a time of profound globalization.
Trade in the mid 19th century largely followed the British World System; a free world market centered in London and its financial web. However this system was unstable, experiencing a long depression (1873-96), state defaults, and regular financial panics. Challenges from competitors,
especially Germany, soon followed, and by the end of the 19th century the trade landscape had shifted, and a new nationalist era ushered in. New boarders appeared, trade restrictions were imposed, and strong cartels limited competition, within the multinational Austro-Hungarian Empire as well. The European powers competed for African resources and parted the continent. This age culminated into a denser cluster of wars and deeper crisis, from WWI to the close of WWII in 1945.
To understand how trade dynamics might evidence and interact with these various processes, information measures - including Shannon entropy and KL-divergence - were calculated on the distribution of imported and exported tonnages by nation over time and on the balance sheets of the Generali insurance company, the largest Austro-Hungarian insurer, from 1851 to 1910.
The next phase of the project will include more detailed analysis, involving data on goods per country and Generali's marine insurance contracts.
Globalization is a phenomenon lasting centuries. Contributing factors, including the import and export dynamics of major nations, are many in number and complex in their interactions. This study considers the behavior of one of the worlds 10 largest ports - Trieste - within the Austria-Hungarian empire from the mid 19th century through to the start of World War I (WWI), a time of profound globalization.
Trade in the mid 19th century largely followed the British World System; a free world market centered in London and its financial web. However this system was unstable, experiencing a long depression (1873-96), state defaults, and regular financial panics. Challenges from competitors,
especially Germany, soon followed, and by the end of the 19th century the trade landscape had shifted, and a new nationalist era ushered in. New boarders appeared, trade restrictions were imposed, and strong cartels limited competition, within the multinational Austro-Hungarian Empire as well. The European powers competed for African resources and parted the continent. This age culminated into a denser cluster of wars and deeper crisis, from WWI to the close of WWII in 1945.
To understand how trade dynamics might evidence and interact with these various processes, information measures - including Shannon entropy and KL-divergence - were calculated on the distribution of imported and exported tonnages by nation over time and on the balance sheets of the Generali insurance company, the largest Austro-Hungarian insurer, from 1851 to 1910.
The next phase of the project will include more detailed analysis, involving data on goods per country and Generali's marine insurance contracts.