James Grace, Ph.D. (Former Employee)
Science and Products
Coastal Wetland Vulnerability to Climate Change and Sea-Level Rise: Understanding Ecological Thresholds and Ecosystem Transformations
Eighteen USGS coastal scientists from all four coasts of the conterminous United States are working together to advance the understanding of climate change and sea-level rise impacts to coastal wetlands.
By
California Water Science Center, Chesapeake Bay Activities, Eastern Ecological Science Center, Florence Bascom Geoscience Center, Great Lakes Science Center, Pacific Coastal and Marine Science Center, St. Petersburg Coastal and Marine Science Center, Western Ecological Research Center (WERC), Western Geographic Science Center, Wetland and Aquatic Research Center , Woods Hole Coastal and Marine Science Center
Synthesizing Surface Elevation Change Data to Advance Understanding of Sea-level Rise Impacts to Mangrove Forests and Salt Marshes
USGS and NPS partners are working together to analyze and synthesize long-term SET-MH measurements to improve understanding of coastal wetland soil elevation change and ecological responses to sea-level rise.
The Response of Coastal Wetlands to Sea-level Rise: Understanding how Macroscale Drivers Influence Local Processes and Feedbacks
The purpose of this work is to advance our understanding of how coastal wetland responses to sea-level rise (SLR) within the conterminous United States are likely to vary as a function of local, regional, and macroscale drivers, including climate. Based on our interactions with managers and decision makers, as well as our knowledge of the current state of the science, we propose to: (a) conduct a...
The response of coastal wetlands to sea-level rise: Understanding how macroscale drivers influence local processes and feedbacks
The purpose of this work is to advance our understanding of how coastal wetland responses to SLR within the conterminous United States are likely to vary as a function of local, regional, and macroscale drivers, including climate. Based on our interactions with managers and decision makers, as well as our knowledge of the current state of the science, we propose to (a) conduct a national synoptic...
Development of a Multimetric Index for Integrated Assessment of Salt Marsh Condition in the Northeast Coastal and Barrier Network
Salt marsh ecosystems along all US coastlines have been altered, degraded, and destroyed by human activities, including ditching and drainage of the marsh platform, tidal restrictions, discharge of pollutants, and introduction of invasive species. The National Park Service conducts long-term monitoring of salt marsh vegetation and nekton (fish and free-swimming crustaceans) to provide information...
Quantitative Analysis Using Structural Equation Modeling
USGS scientists have been involved for a number of years in the development and use of Structural Equation Modeling (SEM). This methodology represents an approach to statistical modeling that focuses on the study of complex cause-effect hypotheses about the mechanisms operating in systems. SEM is increasingly used in ecological and environmental studies and this site seeks to provide educational...
Improving Our Ability to Forecast Tidal Marsh Response to Sea Level Rise
Our overall objective is to understand what controls the vulnerability of coastal marshes to risks associated with global change drivers and rising sea levels. Fundamental questions pertaining to coastal wetland vulnerability still need to be addressed. What factors explain spatial and geographic variation in tidal wetland vulnerability? How do short term climatic events (storms) influence the...
Structural Equation Modeling in Support of Conservation
Understanding systems sometimes requires approaches that allow for both the discovery of the a system's structure and the estimation of its implications. Structural Equation Modeling - SEM - is one tool scientists use to better understand the complex world in which we live.
Mechanisms of Coastal Marsh Elevation Regulation
Sediment deposition serves an important role in the long-term maintenance of coastal marshes. USGS investigates the mechanisms of coastal marsh elevation regulation to help predict marsh sediment requirements under various sea level rise scenarios.
Filter Total Items: 188
Climate and local environment structure asynchrony and the stability of primary production in grasslands Climate and local environment structure asynchrony and the stability of primary production in grasslands
Aim Climate variability threatens to destabilize production in many ecosystems. Asynchronous species dynamics may buffer against such variability when a decrease in performance by some species is offset by an increase in performance of others. However, high climatic variability can eliminate species through stochastic extinctions or cause similar stress responses among species that...
Authors
B. Gilbert, A.S. MacDougall, T. Kadoya, M. Akasaka, J. R. Bennett, E.M. Lind, H. Flores-Moreno, J. Firn, Y. Hautier, E.T. Borer, E.W. Seabloom, P.B. Adler, E.E. Cleland, James B. Grace, W.S. Harpole, E.H. Esch, J.L. Moore, J. Knops, R. McCulley, B. Mortensen, J. Bakker, P.A. Fay
A 'weight of evidence' approach to evaluating structural equation models A 'weight of evidence' approach to evaluating structural equation models
It is possible that model selection has been the most researched and most discussed topic in the history of both statistics and structural equation modeling (SEM). The reason for this is because selecting one model for interpretive use from amongst many possible models is both essential and difficult. The published protocols and advice for model evaluation and selection in SEM studies...
Authors
James B. Grace
Structural equation modeling Structural equation modeling
This chapter introduces background and historical information on how structural equation modeling (SEM) came to be developed. Then, the main differences between SEM and earlier multivariate methods are explained. The chapter describes three main applications of SEM: path analysis, factor analysis, and hybrid models. Some computer programs are recommended for these applications. The step...
Authors
Matt Miller, Ivana Tasic, Torrey Lyons, Reid Ewing, James B. Grace
Conceptual frameworks Conceptual frameworks
The chapter starts by addressing some of the issues that come from not using a conceptual framework. This point is illustrated using an example with causal factors. The chapter then goes on to explain the mechanics of establishing conceptual frameworks. Lastly, it lays out a step-by-step guide on how to create a framework—generating a set of concepts, specifying the relations between...
Authors
Keunhyun Park, James B. Grace, Reid Ewing
Scientist’s guide to developing explanatory statistical models using causal analysis principles Scientist’s guide to developing explanatory statistical models using causal analysis principles
Recent discussions of model selection and multimodel inference highlight a general challenge for researchers, which is how to clearly convey the explanatory content of a hypothesized model or set of competing models. The advice from statisticians for scientists employing multimodel inference is to develop a well‐thought‐out set of candidate models for comparison, though precise...
Authors
James B. Grace, Kathryn Irvine
The importance of natural versus human factors for ecological conditions of streams and rivers The importance of natural versus human factors for ecological conditions of streams and rivers
Streams are influenced by watershed-scale factors, such as climate, geology, topography, hydrology, and soils, which mostly vary naturally among sites, as well as human factors, agriculture and urban development. Thus, natural factors could complicate assessment of human disturbance. In the present study, we use structural equation modeling and data from the 2008-2009 United States...
Authors
Tao Tang, R. Jan Stevenson, James Grace
Climatic controls on the distribution of foundation plant species in coastal wetlands of the conterminous United States: Knowledge gaps and emerging research needs Climatic controls on the distribution of foundation plant species in coastal wetlands of the conterminous United States: Knowledge gaps and emerging research needs
Foundation plant species play a critical role in coastal wetlands, often modifying abiotic conditions that are too stressful for most organisms and providing the primary habitat features that support entire ecological communities. Here, we consider the influence of climatic drivers on the distribution of foundation plant species within coastal wetlands of the conterminous USA. Using...
Authors
Michael J. Osland, James B. Grace, Glenn R. Guntenspergen, Karen Thorne, Joel A. Carr, Laura Feher
Discoveries and novel insights in ecology using structural equation modeling Discoveries and novel insights in ecology using structural equation modeling
As we enter the era of data science (Lortie 2018), quantitative analysis methodologies are proliferating rapidly, leaving ecologists with the task of choosing among many alternatives. The use of structural equation modeling (SEM) by ecologists has increased in recent years, prompting us to ask users a number of questions about their experience with the methodology. Responses indicate an
Authors
Daniel C. Laughlin, James B. Grace
Patterns of resource allocation in a coastal marsh plant (Schoenoplectus americanus) along a sediment-addition gradient Patterns of resource allocation in a coastal marsh plant (Schoenoplectus americanus) along a sediment-addition gradient
Reductions in sediment delivery to coastal marshes increase their vulnerability to relative sea-level rise. Sediment pulses from storm events and commercial dredge-spray operations (e.g., beneficial use) represent increasingly important sediment sources to otherwise sediment-deprived marshes. These sediments can stimulate plant growth by providing nutrient and elevation subsidies, with...
Authors
Nigel A. Temple, James B. Grace, Julia A Cherry
Hurricane Sandy impacts on coastal wetland resilience Hurricane Sandy impacts on coastal wetland resilience
The goal of this research was to evaluate the impacts of Hurricane Sandy on surface elevation trends in estuarine marshes located across the northeast region of the United States from Virginia to Maine using data from an opportunistic (in other words, not strategic) and collaborative network (from here on, an opportunistic network) of surface elevation table-marker horizon (SET-MH)...
Authors
Donald R. Cahoon, Jennifer H. Olker, Alice G. Yeates, Glenn R. Guntenspergen, James B. Grace, Susan C. Adamowicz, Shimon C. Anisfeld, Andrew H. Baldwin, Nels Barrett, Leah Beckett, Alice Benzecry, Linda K. Blum, David M. Burdick, William Crouch, Marci Cole Ekberg, Sarah Fernald, Kristin Wilson Grimes, Joseph Grzyb, Ellen Kracauer Hartig, Danielle A. Kreeger, Marit Larson, Scott Lerberg, James C. Lynch, Nicole Maher, Martha Maxwell-Doyle, Laura R. Mitchell, Jordan Mora, Victoria O’Neill, Angela Padeletti, Diann J. Prosser, Tracy Quirk, Kenneth B. Raposa, William G. Reay, Drexel Siok, Christopher Snow, Adam Starke, J. Court Stevenson, Lorie Staver, Vincent Turner
The plant diversity sampling design for The National Ecological Observatory Network The plant diversity sampling design for The National Ecological Observatory Network
The National Ecological Observatory Network (NEON) is designed to facilitate an understanding of the impact of environmental change on ecological systems. Observations of plant diversity—responsive to changes in climate, disturbance, and land use, and ecologically linked to soil, biogeochemistry, and organisms—result in NEON data products that cross a range of organizational levels...
Authors
David T. Barnett, Peter B. Adler, Benjamin R. Chemel, Paul A. Duffy, Brian J. Enquist, James B. Grace, Susan P. Harrison, Robert K. Peet, David S. Schimel, Thomas J. Stohlgren, Mark Vellend
Climate and plant controls on soil organic matter in coastal wetlands Climate and plant controls on soil organic matter in coastal wetlands
Coastal wetlands are among the most productive and carbon‐rich ecosystems on Earth. Long‐term carbon storage in coastal wetlands occurs primarily belowground as soil organic matter (SOM). In addition to serving as a carbon sink, SOM influences wetland ecosystem structure, function, and stability. To anticipate and mitigate the effects of climate change, there is a need to advance...
Authors
Michael J. Osland, Christopher A. Gabler, James B. Grace, Richard H. Day, Meagan L. McCoy, Jennie L. McLeod, Andrew S. From, Nicholas M. Enwright, Laura C. Feher, Camille L. Stagg, Stephen B. Hartley
Science and Products
Coastal Wetland Vulnerability to Climate Change and Sea-Level Rise: Understanding Ecological Thresholds and Ecosystem Transformations
Eighteen USGS coastal scientists from all four coasts of the conterminous United States are working together to advance the understanding of climate change and sea-level rise impacts to coastal wetlands.
By
California Water Science Center, Chesapeake Bay Activities, Eastern Ecological Science Center, Florence Bascom Geoscience Center, Great Lakes Science Center, Pacific Coastal and Marine Science Center, St. Petersburg Coastal and Marine Science Center, Western Ecological Research Center (WERC), Western Geographic Science Center, Wetland and Aquatic Research Center , Woods Hole Coastal and Marine Science Center
Synthesizing Surface Elevation Change Data to Advance Understanding of Sea-level Rise Impacts to Mangrove Forests and Salt Marshes
USGS and NPS partners are working together to analyze and synthesize long-term SET-MH measurements to improve understanding of coastal wetland soil elevation change and ecological responses to sea-level rise.
The Response of Coastal Wetlands to Sea-level Rise: Understanding how Macroscale Drivers Influence Local Processes and Feedbacks
The purpose of this work is to advance our understanding of how coastal wetland responses to sea-level rise (SLR) within the conterminous United States are likely to vary as a function of local, regional, and macroscale drivers, including climate. Based on our interactions with managers and decision makers, as well as our knowledge of the current state of the science, we propose to: (a) conduct a...
The response of coastal wetlands to sea-level rise: Understanding how macroscale drivers influence local processes and feedbacks
The purpose of this work is to advance our understanding of how coastal wetland responses to SLR within the conterminous United States are likely to vary as a function of local, regional, and macroscale drivers, including climate. Based on our interactions with managers and decision makers, as well as our knowledge of the current state of the science, we propose to (a) conduct a national synoptic...
Development of a Multimetric Index for Integrated Assessment of Salt Marsh Condition in the Northeast Coastal and Barrier Network
Salt marsh ecosystems along all US coastlines have been altered, degraded, and destroyed by human activities, including ditching and drainage of the marsh platform, tidal restrictions, discharge of pollutants, and introduction of invasive species. The National Park Service conducts long-term monitoring of salt marsh vegetation and nekton (fish and free-swimming crustaceans) to provide information...
Quantitative Analysis Using Structural Equation Modeling
USGS scientists have been involved for a number of years in the development and use of Structural Equation Modeling (SEM). This methodology represents an approach to statistical modeling that focuses on the study of complex cause-effect hypotheses about the mechanisms operating in systems. SEM is increasingly used in ecological and environmental studies and this site seeks to provide educational...
Improving Our Ability to Forecast Tidal Marsh Response to Sea Level Rise
Our overall objective is to understand what controls the vulnerability of coastal marshes to risks associated with global change drivers and rising sea levels. Fundamental questions pertaining to coastal wetland vulnerability still need to be addressed. What factors explain spatial and geographic variation in tidal wetland vulnerability? How do short term climatic events (storms) influence the...
Structural Equation Modeling in Support of Conservation
Understanding systems sometimes requires approaches that allow for both the discovery of the a system's structure and the estimation of its implications. Structural Equation Modeling - SEM - is one tool scientists use to better understand the complex world in which we live.
Mechanisms of Coastal Marsh Elevation Regulation
Sediment deposition serves an important role in the long-term maintenance of coastal marshes. USGS investigates the mechanisms of coastal marsh elevation regulation to help predict marsh sediment requirements under various sea level rise scenarios.
Filter Total Items: 188
Climate and local environment structure asynchrony and the stability of primary production in grasslands Climate and local environment structure asynchrony and the stability of primary production in grasslands
Aim Climate variability threatens to destabilize production in many ecosystems. Asynchronous species dynamics may buffer against such variability when a decrease in performance by some species is offset by an increase in performance of others. However, high climatic variability can eliminate species through stochastic extinctions or cause similar stress responses among species that...
Authors
B. Gilbert, A.S. MacDougall, T. Kadoya, M. Akasaka, J. R. Bennett, E.M. Lind, H. Flores-Moreno, J. Firn, Y. Hautier, E.T. Borer, E.W. Seabloom, P.B. Adler, E.E. Cleland, James B. Grace, W.S. Harpole, E.H. Esch, J.L. Moore, J. Knops, R. McCulley, B. Mortensen, J. Bakker, P.A. Fay
A 'weight of evidence' approach to evaluating structural equation models A 'weight of evidence' approach to evaluating structural equation models
It is possible that model selection has been the most researched and most discussed topic in the history of both statistics and structural equation modeling (SEM). The reason for this is because selecting one model for interpretive use from amongst many possible models is both essential and difficult. The published protocols and advice for model evaluation and selection in SEM studies...
Authors
James B. Grace
Structural equation modeling Structural equation modeling
This chapter introduces background and historical information on how structural equation modeling (SEM) came to be developed. Then, the main differences between SEM and earlier multivariate methods are explained. The chapter describes three main applications of SEM: path analysis, factor analysis, and hybrid models. Some computer programs are recommended for these applications. The step...
Authors
Matt Miller, Ivana Tasic, Torrey Lyons, Reid Ewing, James B. Grace
Conceptual frameworks Conceptual frameworks
The chapter starts by addressing some of the issues that come from not using a conceptual framework. This point is illustrated using an example with causal factors. The chapter then goes on to explain the mechanics of establishing conceptual frameworks. Lastly, it lays out a step-by-step guide on how to create a framework—generating a set of concepts, specifying the relations between...
Authors
Keunhyun Park, James B. Grace, Reid Ewing
Scientist’s guide to developing explanatory statistical models using causal analysis principles Scientist’s guide to developing explanatory statistical models using causal analysis principles
Recent discussions of model selection and multimodel inference highlight a general challenge for researchers, which is how to clearly convey the explanatory content of a hypothesized model or set of competing models. The advice from statisticians for scientists employing multimodel inference is to develop a well‐thought‐out set of candidate models for comparison, though precise...
Authors
James B. Grace, Kathryn Irvine
The importance of natural versus human factors for ecological conditions of streams and rivers The importance of natural versus human factors for ecological conditions of streams and rivers
Streams are influenced by watershed-scale factors, such as climate, geology, topography, hydrology, and soils, which mostly vary naturally among sites, as well as human factors, agriculture and urban development. Thus, natural factors could complicate assessment of human disturbance. In the present study, we use structural equation modeling and data from the 2008-2009 United States...
Authors
Tao Tang, R. Jan Stevenson, James Grace
Climatic controls on the distribution of foundation plant species in coastal wetlands of the conterminous United States: Knowledge gaps and emerging research needs Climatic controls on the distribution of foundation plant species in coastal wetlands of the conterminous United States: Knowledge gaps and emerging research needs
Foundation plant species play a critical role in coastal wetlands, often modifying abiotic conditions that are too stressful for most organisms and providing the primary habitat features that support entire ecological communities. Here, we consider the influence of climatic drivers on the distribution of foundation plant species within coastal wetlands of the conterminous USA. Using...
Authors
Michael J. Osland, James B. Grace, Glenn R. Guntenspergen, Karen Thorne, Joel A. Carr, Laura Feher
Discoveries and novel insights in ecology using structural equation modeling Discoveries and novel insights in ecology using structural equation modeling
As we enter the era of data science (Lortie 2018), quantitative analysis methodologies are proliferating rapidly, leaving ecologists with the task of choosing among many alternatives. The use of structural equation modeling (SEM) by ecologists has increased in recent years, prompting us to ask users a number of questions about their experience with the methodology. Responses indicate an
Authors
Daniel C. Laughlin, James B. Grace
Patterns of resource allocation in a coastal marsh plant (Schoenoplectus americanus) along a sediment-addition gradient Patterns of resource allocation in a coastal marsh plant (Schoenoplectus americanus) along a sediment-addition gradient
Reductions in sediment delivery to coastal marshes increase their vulnerability to relative sea-level rise. Sediment pulses from storm events and commercial dredge-spray operations (e.g., beneficial use) represent increasingly important sediment sources to otherwise sediment-deprived marshes. These sediments can stimulate plant growth by providing nutrient and elevation subsidies, with...
Authors
Nigel A. Temple, James B. Grace, Julia A Cherry
Hurricane Sandy impacts on coastal wetland resilience Hurricane Sandy impacts on coastal wetland resilience
The goal of this research was to evaluate the impacts of Hurricane Sandy on surface elevation trends in estuarine marshes located across the northeast region of the United States from Virginia to Maine using data from an opportunistic (in other words, not strategic) and collaborative network (from here on, an opportunistic network) of surface elevation table-marker horizon (SET-MH)...
Authors
Donald R. Cahoon, Jennifer H. Olker, Alice G. Yeates, Glenn R. Guntenspergen, James B. Grace, Susan C. Adamowicz, Shimon C. Anisfeld, Andrew H. Baldwin, Nels Barrett, Leah Beckett, Alice Benzecry, Linda K. Blum, David M. Burdick, William Crouch, Marci Cole Ekberg, Sarah Fernald, Kristin Wilson Grimes, Joseph Grzyb, Ellen Kracauer Hartig, Danielle A. Kreeger, Marit Larson, Scott Lerberg, James C. Lynch, Nicole Maher, Martha Maxwell-Doyle, Laura R. Mitchell, Jordan Mora, Victoria O’Neill, Angela Padeletti, Diann J. Prosser, Tracy Quirk, Kenneth B. Raposa, William G. Reay, Drexel Siok, Christopher Snow, Adam Starke, J. Court Stevenson, Lorie Staver, Vincent Turner
The plant diversity sampling design for The National Ecological Observatory Network The plant diversity sampling design for The National Ecological Observatory Network
The National Ecological Observatory Network (NEON) is designed to facilitate an understanding of the impact of environmental change on ecological systems. Observations of plant diversity—responsive to changes in climate, disturbance, and land use, and ecologically linked to soil, biogeochemistry, and organisms—result in NEON data products that cross a range of organizational levels...
Authors
David T. Barnett, Peter B. Adler, Benjamin R. Chemel, Paul A. Duffy, Brian J. Enquist, James B. Grace, Susan P. Harrison, Robert K. Peet, David S. Schimel, Thomas J. Stohlgren, Mark Vellend
Climate and plant controls on soil organic matter in coastal wetlands Climate and plant controls on soil organic matter in coastal wetlands
Coastal wetlands are among the most productive and carbon‐rich ecosystems on Earth. Long‐term carbon storage in coastal wetlands occurs primarily belowground as soil organic matter (SOM). In addition to serving as a carbon sink, SOM influences wetland ecosystem structure, function, and stability. To anticipate and mitigate the effects of climate change, there is a need to advance...
Authors
Michael J. Osland, Christopher A. Gabler, James B. Grace, Richard H. Day, Meagan L. McCoy, Jennie L. McLeod, Andrew S. From, Nicholas M. Enwright, Laura C. Feher, Camille L. Stagg, Stephen B. Hartley