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
Structural equation models of VMT growth in US urbanised areas. Structural equation models of VMT growth in US urbanised areas.
Vehicle miles travelled (VMT) is a primary performance indicator for land use and transportation, bringing with it both positive and negative externalities. This study updates and refines previous work on VMT in urbanised areas, using recent data, additional metrics and structural equation modelling (SEM). In a cross-sectional model for 2010, population, income and freeway capacity are...
Authors
Reid Ewing, Shima Hamidi, Frank Gallivan, Arthur C. Nelson, James B. Grace
Functional diversity supports the physiological tolerance hypothesis for plant species richness along climatic gradients Functional diversity supports the physiological tolerance hypothesis for plant species richness along climatic gradients
1. The physiological tolerance hypothesis proposes that plant species richness is highest in warm and/or wet climates because a wider range of functional strategies can persist under such conditions. Functional diversity metrics, combined with statistical modeling, offer new ways to test whether diversity-environment relationships are consistent with this hypothesis. 2. In a classic...
Authors
Marko J. Spasojevic, James B. Grace, Susan Harrison, Ellen Ingman Damschen
Resilience to stress and disturbance, and resistance to Bromus tectorum L. invasion in cold desert shrublands of western North America Resilience to stress and disturbance, and resistance to Bromus tectorum L. invasion in cold desert shrublands of western North America
Alien grass invasions in arid and semi-arid ecosystems are resulting in grass–fire cycles and ecosystem-level transformations that severely diminish ecosystem services. Our capacity to address the rapid and complex changes occurring in these ecosystems can be enhanced by developing an understanding of the environmental factors and ecosystem attributes that determine resilience of native...
Authors
Jeanne C. Chambers, Bethany A. Bradley, Cynthia S. Brown, Carla D'Antonio, Matthew J. Germino, James B. Grace, Stuart P. Hardegree, Richard F. Miller, David A. Pyke
Direct and indirect effects of land use on floral resources and flower-visiting insects across an urban landscape Direct and indirect effects of land use on floral resources and flower-visiting insects across an urban landscape
Although urban areas are often considered to have uniformly negative effects on biodiversity, cities are most accurately characterized as heterogeneous mosaics of buildings, streets, parks, and gardens that include both ‘good’ and ‘bad’ areas for wildlife. However, to date, few studies have evaluated how human impacts vary in direction and magnitude across a heterogeneous urban landscape...
Authors
K.C. Matteson, James B. Grace, E.S. Minor
Evidence that acidification-induced declines in plant diversity and productivity are mediated by changes in below-ground communities and soil properties in a semi-arid steppe Evidence that acidification-induced declines in plant diversity and productivity are mediated by changes in below-ground communities and soil properties in a semi-arid steppe
Anthropogenic acid deposition–induced soil acidification is one of the major threats to biodiversity, ecosystem functioning and services. Few studies, however, have explored in detail how above-ground changes in plant species richness and productivity resulting from soil acidification are mediated by effects on below-ground biota and soil properties. To increase our understanding of this...
Authors
Dima Chen, Zhichun Lan, Xue Bai, James B. Grace, Yongfei Bai
Conditions favouring Bromus tectorum dominance of endangered sagebrush steppe ecosystems Conditions favouring Bromus tectorum dominance of endangered sagebrush steppe ecosystems
1. Ecosystem invasibility is determined by combinations of environmental variables, invader attributes, disturbance regimes, competitive abilities of resident species and evolutionary history between residents and disturbance regimes. Understanding the relative importance of each factor is critical to limiting future invasions and restoring ecosystems. 2. We investigated factors...
Authors
Michael D. Reisner, James B. Grace, David A. Pyke, Paul S. Doescher
Predicting ecosystem stability from community composition and biodiversity Predicting ecosystem stability from community composition and biodiversity
As biodiversity is declining at an unprecedented rate, an important current scientific challenge is to understand and predict the consequences of biodiversity loss. Here, we develop a theory that predicts the temporal variability of community biomass from the properties of individual component species in monoculture. Our theory shows that biodiversity stabilises ecosystems through three...
Authors
Claire de Mazancourt, Forest Isbell, Allen Larocque, Frank Berendse, Enrica De Luca, James B. Grace, Bart Haegeman, H. Wayne Polley, Christiane Roscher, Bernhard Schmid, David Tilman, Jasper van Ruijven, Alexandra Weigelt, Brian J. Wilsey, Michel Loreau
Controls of biological soil crust cover and composition shift with succession in sagebrush shrub-steppe Controls of biological soil crust cover and composition shift with succession in sagebrush shrub-steppe
Successional stage may determine strength and causal direction of interactions among abiotic and biotic factors; e.g., species that facilitate the establishment of other species may later compete with them. We evaluated multivariate hypotheses about abiotic and biotic factors shaping biological soil crusts (BSCs) in early and late successional stages. We surveyed vegetation and BSC in...
Authors
E. Dettweiler-Robinson, J.D. Bakker, J.B. Grace
How does pedogenesis drive plant diversity? How does pedogenesis drive plant diversity?
Some of the most species-rich plant communities occur on ancient, strongly weathered soils, whereas those on recently developed soils tend to be less diverse. Mechanisms underlying this well-known pattern, however, remain unresolved. Here, we present a conceptual model describing alternative mechanisms by which pedogenesis (the process of soil formation) might drive plant diversity. We...
Authors
Etienne Laliberte, James B. Grace, Michael A. Huston, Hans Lambers, Francois P. Teste, Benjamin L. Turner, David A. Wardle
A causal examination of the effects of confounding factors on multimetric indices A causal examination of the effects of confounding factors on multimetric indices
The development of multimetric indices (MMIs) as a means of providing integrative measures of ecosystem condition is becoming widespread. An increasingly recognized problem for the interpretability of MMIs is controlling for the potentially confounding influences of environmental covariates. Most common approaches to handling covariates are based on simple notions of statistical control...
Authors
Donald R. Schoolmaster, James B. Grace, E. William Schweiger, Brian R. Mitchell, Glenn R. Guntenspergen
Streams in the urban heat island: spatial and temporal variability in temperature Streams in the urban heat island: spatial and temporal variability in temperature
Streams draining urban heat islands tend to be hotter than rural and forested streams at baseflow because of warmer urban air and ground temperatures, paved surfaces, and decreased riparian canopy. Urban infrastructure efficiently routes runoff over hot impervious surfaces and through storm drains directly into streams and can lead to rapid, dramatic increases in temperature. Thermal...
Authors
Kayleigh A. Somers, Emily S. Bernhardt, James B. Grace, Brooke A. Hassett, Elizabeth B. Sudduth, Siyi Wang, Dean L. Urban
Temporal shifts in top-down vs. bottom-up control of epiphytic algae in a seagrass ecosystem Temporal shifts in top-down vs. bottom-up control of epiphytic algae in a seagrass ecosystem
In coastal marine food webs, small invertebrate herbivores (mesograzers) have long been hypothesized to occupy an important position facilitating dominance of habitat-forming macrophytes by grazing competitively superior epiphytic algae. Because of the difficulty of manipulating mesograzers in the field, however, their impacts on community organization have rarely been rigorously...
Authors
Matthew A. Whalen, J. Emmett Duffy, James B. Grace
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
Structural equation models of VMT growth in US urbanised areas. Structural equation models of VMT growth in US urbanised areas.
Vehicle miles travelled (VMT) is a primary performance indicator for land use and transportation, bringing with it both positive and negative externalities. This study updates and refines previous work on VMT in urbanised areas, using recent data, additional metrics and structural equation modelling (SEM). In a cross-sectional model for 2010, population, income and freeway capacity are...
Authors
Reid Ewing, Shima Hamidi, Frank Gallivan, Arthur C. Nelson, James B. Grace
Functional diversity supports the physiological tolerance hypothesis for plant species richness along climatic gradients Functional diversity supports the physiological tolerance hypothesis for plant species richness along climatic gradients
1. The physiological tolerance hypothesis proposes that plant species richness is highest in warm and/or wet climates because a wider range of functional strategies can persist under such conditions. Functional diversity metrics, combined with statistical modeling, offer new ways to test whether diversity-environment relationships are consistent with this hypothesis. 2. In a classic...
Authors
Marko J. Spasojevic, James B. Grace, Susan Harrison, Ellen Ingman Damschen
Resilience to stress and disturbance, and resistance to Bromus tectorum L. invasion in cold desert shrublands of western North America Resilience to stress and disturbance, and resistance to Bromus tectorum L. invasion in cold desert shrublands of western North America
Alien grass invasions in arid and semi-arid ecosystems are resulting in grass–fire cycles and ecosystem-level transformations that severely diminish ecosystem services. Our capacity to address the rapid and complex changes occurring in these ecosystems can be enhanced by developing an understanding of the environmental factors and ecosystem attributes that determine resilience of native...
Authors
Jeanne C. Chambers, Bethany A. Bradley, Cynthia S. Brown, Carla D'Antonio, Matthew J. Germino, James B. Grace, Stuart P. Hardegree, Richard F. Miller, David A. Pyke
Direct and indirect effects of land use on floral resources and flower-visiting insects across an urban landscape Direct and indirect effects of land use on floral resources and flower-visiting insects across an urban landscape
Although urban areas are often considered to have uniformly negative effects on biodiversity, cities are most accurately characterized as heterogeneous mosaics of buildings, streets, parks, and gardens that include both ‘good’ and ‘bad’ areas for wildlife. However, to date, few studies have evaluated how human impacts vary in direction and magnitude across a heterogeneous urban landscape...
Authors
K.C. Matteson, James B. Grace, E.S. Minor
Evidence that acidification-induced declines in plant diversity and productivity are mediated by changes in below-ground communities and soil properties in a semi-arid steppe Evidence that acidification-induced declines in plant diversity and productivity are mediated by changes in below-ground communities and soil properties in a semi-arid steppe
Anthropogenic acid deposition–induced soil acidification is one of the major threats to biodiversity, ecosystem functioning and services. Few studies, however, have explored in detail how above-ground changes in plant species richness and productivity resulting from soil acidification are mediated by effects on below-ground biota and soil properties. To increase our understanding of this...
Authors
Dima Chen, Zhichun Lan, Xue Bai, James B. Grace, Yongfei Bai
Conditions favouring Bromus tectorum dominance of endangered sagebrush steppe ecosystems Conditions favouring Bromus tectorum dominance of endangered sagebrush steppe ecosystems
1. Ecosystem invasibility is determined by combinations of environmental variables, invader attributes, disturbance regimes, competitive abilities of resident species and evolutionary history between residents and disturbance regimes. Understanding the relative importance of each factor is critical to limiting future invasions and restoring ecosystems. 2. We investigated factors...
Authors
Michael D. Reisner, James B. Grace, David A. Pyke, Paul S. Doescher
Predicting ecosystem stability from community composition and biodiversity Predicting ecosystem stability from community composition and biodiversity
As biodiversity is declining at an unprecedented rate, an important current scientific challenge is to understand and predict the consequences of biodiversity loss. Here, we develop a theory that predicts the temporal variability of community biomass from the properties of individual component species in monoculture. Our theory shows that biodiversity stabilises ecosystems through three...
Authors
Claire de Mazancourt, Forest Isbell, Allen Larocque, Frank Berendse, Enrica De Luca, James B. Grace, Bart Haegeman, H. Wayne Polley, Christiane Roscher, Bernhard Schmid, David Tilman, Jasper van Ruijven, Alexandra Weigelt, Brian J. Wilsey, Michel Loreau
Controls of biological soil crust cover and composition shift with succession in sagebrush shrub-steppe Controls of biological soil crust cover and composition shift with succession in sagebrush shrub-steppe
Successional stage may determine strength and causal direction of interactions among abiotic and biotic factors; e.g., species that facilitate the establishment of other species may later compete with them. We evaluated multivariate hypotheses about abiotic and biotic factors shaping biological soil crusts (BSCs) in early and late successional stages. We surveyed vegetation and BSC in...
Authors
E. Dettweiler-Robinson, J.D. Bakker, J.B. Grace
How does pedogenesis drive plant diversity? How does pedogenesis drive plant diversity?
Some of the most species-rich plant communities occur on ancient, strongly weathered soils, whereas those on recently developed soils tend to be less diverse. Mechanisms underlying this well-known pattern, however, remain unresolved. Here, we present a conceptual model describing alternative mechanisms by which pedogenesis (the process of soil formation) might drive plant diversity. We...
Authors
Etienne Laliberte, James B. Grace, Michael A. Huston, Hans Lambers, Francois P. Teste, Benjamin L. Turner, David A. Wardle
A causal examination of the effects of confounding factors on multimetric indices A causal examination of the effects of confounding factors on multimetric indices
The development of multimetric indices (MMIs) as a means of providing integrative measures of ecosystem condition is becoming widespread. An increasingly recognized problem for the interpretability of MMIs is controlling for the potentially confounding influences of environmental covariates. Most common approaches to handling covariates are based on simple notions of statistical control...
Authors
Donald R. Schoolmaster, James B. Grace, E. William Schweiger, Brian R. Mitchell, Glenn R. Guntenspergen
Streams in the urban heat island: spatial and temporal variability in temperature Streams in the urban heat island: spatial and temporal variability in temperature
Streams draining urban heat islands tend to be hotter than rural and forested streams at baseflow because of warmer urban air and ground temperatures, paved surfaces, and decreased riparian canopy. Urban infrastructure efficiently routes runoff over hot impervious surfaces and through storm drains directly into streams and can lead to rapid, dramatic increases in temperature. Thermal...
Authors
Kayleigh A. Somers, Emily S. Bernhardt, James B. Grace, Brooke A. Hassett, Elizabeth B. Sudduth, Siyi Wang, Dean L. Urban
Temporal shifts in top-down vs. bottom-up control of epiphytic algae in a seagrass ecosystem Temporal shifts in top-down vs. bottom-up control of epiphytic algae in a seagrass ecosystem
In coastal marine food webs, small invertebrate herbivores (mesograzers) have long been hypothesized to occupy an important position facilitating dominance of habitat-forming macrophytes by grazing competitively superior epiphytic algae. Because of the difficulty of manipulating mesograzers in the field, however, their impacts on community organization have rarely been rigorously...
Authors
Matthew A. Whalen, J. Emmett Duffy, James B. Grace