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Laura J Moore - One of the best experts on this subject based on the ideXlab platform.
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connectivity in coastal systems Barrier Island vegetation influences upland migration in a changing climate
Global Change Biology, 2019Co-Authors: Julie C Zinnert, Laura J Moore, Stephen M Via, Benjamin P Nettleton, Philip A Tuley, Jon Anthony StallinsAbstract:Due to their position at the land-sea interface, Barrier Islands are vulnerable to both oceanic and atmospheric climate change-related drivers. In response to relative sea-level rise, Barrier Islands tend to migrate landward via overwash processes which deposit sediment onto the backBarrier marsh, thus maintaining elevation above sea level. In this paper, we assess the importance of interior upland vegetation and sediment transport (from upland to marsh) on the movement of the marsh-upland boundary in a transgressive Barrier system along the mid-Atlantic Coast. We hypothesize that recent woody expansion is altering the rate of marsh to upland conversion. Using Landsat imagery over a 32 year time period (1984-2016), we quantify transitions between land cover (bare, grassland, woody vegetation, and marsh) and the marsh-upland boundary. We find that the Virginia Barrier Islands have both gains and losses in backBarrier marsh and upland, with 19% net loss from the system during the timeframe of the study and increased variance in marsh to upland conversion. This is consistent with recent work indicating a shift toward increasing rates of landward Barrier Island migration. Despite a net loss of upland area, macroclimatic winter warming resulted in 41% increase in woody vegetation in protected, low-elevation areas, introducing new ecological scenarios that increase resistance to sediment movement from upland to marsh. Our analysis demonstrates how the interplay between elevation and interior Island vegetative cover influences landward migration of the boundary between upland and marsh (a previously underappreciated indicator that an Island is migrating), and thus, the importance of including ecological processes in the Island interior into coastal modeling of Barrier Island migration and sediment movement across the Barrier landscape.
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Barrier Island bistability induced by biophysical interactions
Nature Climate Change, 2015Co-Authors: Orencio Duran Vinent, Laura J MooreAbstract:Barrier Islands represent about 10% of the world’s coastline and perform many services including coastal protection. A study now shows that Islands exhibit a bistable response to environmental change. Improved understanding of these mechanisms can help to predict future transitions in Barrier Island state.
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complexities in Barrier Island response to sea level rise insights from numerical model experiments north carolina outer banks
Journal of Geophysical Research, 2010Co-Authors: Laura J Moore, Jeffrey H List, Jeffress S Williams, David StolperAbstract:Using a morphological‐behavior model to conduct sensitivity experiments, weinvestigate the sea level rise response of a complex coastal environment to changes ina variety of factors. Experiments reveal that substrate composition, followed in rankorder by substrate slope, sea level rise rate, and sediment supply rate, are the mostimportant factors in determining Barrier Island response to sea level rise. We find thatgeomorphic threshold crossing, defined as a change in state (e.g., from landward migratingto drowning) that is irreversible over decadal to millennial time scales, is most likely tooccur in muddy coastal systems where the combination of substrate composition, depth‐dependent limitations on shoreface response rates, and substrate erodibility mayprevent sand from being liberated rapidly enough, or in sufficient quantity, to maintain asubaerial Barrier. Analyses indicate that factors affecting sediment availability such aslow substrate sand proportions and high sediment loss rates cause a Barrier to migratelandward along a trajectory having a lower slope than average Barrier Island slope, therebydefining an “effective” Barrier Island slope. Other factors being equal, such Barrierswill tend to be smaller and associated with a more deeply incised shoreface, therebyrequiring less migration per sea level rise increment to liberate sufficient sand to maintainsubaerial exposure than larger, less incised Barriers. As a result, the evolution of larger/lessincised Barriers is more likely to be limited by shoreface erosion rates or substrateerodibility making them more prone to disintegration related to increasing sea level riserates than smaller/more incised Barriers. Thus, the small/deeply incised North CarolinaBarriers are likely to persist in the near term (although their long‐term fate is less certainbecause of the low substrate slopes that will soon be encountered). In aggregate,results point to the importance of system history (e.g., previous slopes, sediment budgets,etc.) in determining migration trajectories and therefore how a Barrier Island will respondto sea level rise. Although simple analytical calculations may predict Barrier responsein simplified coastal environments (e.g., constant slope, constant sea level rise rate, etc.),our model experiments demonstrate that morphological‐behavior modeling is necessary toprovide critical insights regarding changes that may occur in environments havingcomplex geometries, especially when multiple parameters change simultaneously.
Nathaniel G Plant - One of the best experts on this subject based on the ideXlab platform.
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using a bayesian network to predict Barrier Island geomorphologic characteristics
Journal of Geophysical Research, 2015Co-Authors: Benjamin T Gutierrez, Nathaniel G Plant, Robert E Thieler, Aaron M TurecekAbstract:Quantifying geomorphic variability of coastal environments is important for understanding and describing the vulnerability of coastal topography, infrastructure, and ecosystems to future storms and sea level rise. Here we use a Bayesian network (BN) to test the importance of multiple interactions between Barrier Island geomorphic variables. This approach models complex interactions and handles uncertainty, which is intrinsic to future sea level rise, storminess, or anthropogenic processes (e.g., beach nourishment and other forms of coastal management). The BN was developed and tested at Assateague Island, Maryland/Virginia, USA, a Barrier Island with sufficient geomorphic and temporal variability to evaluate our approach. We tested the ability to predict dune height, beach width, and beach height variables using inputs that included longer-term, larger-scale, or external variables (historical shoreline change rates, distances to inlets, Barrier width, mean Barrier elevation, and anthropogenic modification). Data sets from three different years spanning nearly a decade sampled substantial temporal variability and serve as a proxy for analysis of future conditions. We show that distinct geomorphic conditions are associated with different long-term shoreline change rates and that the most skillful predictions of dune height, beach width, and beach height depend on including multiple input variables simultaneously. The predictive relationships are robust to variations in the amount of input data and to variations in model complexity. The resulting model can be used to evaluate scenarios related to coastal management plans and/or future scenarios where shoreline change rates may differ from those observed historically.
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effects of sea level rise on Barrier Island groundwater system dynamics ecohydrological implications
Ecohydrology, 2014Co-Authors: John P Masterson, Benjamin T Gutierrez, Robert E Thieler, Michael N Fienen, Dean B Gesch, Nathaniel G PlantAbstract:We used a numerical model to investigate how a Barrier Island groundwater system responds to increases of up to 60 cm in sea level. We found that a sea-level rise of 20 cm leads to substantial changes in the depth of the water table and the extent and depth of saltwater intrusion, which are key determinants in the establishment, distribution and succession of vegetation assemblages and habitat suitability in Barrier Islands ecosystems. In our simulations, increases in water-table height in areas with a shallow depth to water (or thin vadose zone) resulted in extensive groundwater inundation of land surface and a thinning of the underlying freshwater lens. We demonstrated the interdependence of the groundwater response to Island morphology by evaluating changes at three sites. This interdependence can have a profound effect on ecosystem composition in these fragile coastal landscapes under long-term changing climatic conditions. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.
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a bayesian network approach to predicting nest presence of the federally threatened piping plover charadrius melodus using Barrier Island features
Ecological Modelling, 2014Co-Authors: Katherina D Gieder, Nathaniel G Plant, Benjamin T Gutierrez, Aaron M Turecek, Sarah M Karpanty, James D Fraser, Daniel H Catlin, Robert E ThielerAbstract:Sea-level rise and human development pose significant threats to shorebirds, particularly for species that utilize Barrier Island habitat. The piping plover (Charadrius melodus) is a federally-listed shorebird that nests on Barrier Islands and rapidly responds to changes in its physical environment, making it an excellent species with which to model how shorebird species may respond to habitat change related to sea-level rise and human development. The uncertainty and complexity in predicting sea-level rise, the responses of Barrier Island habitats to sea-level rise, and the responses of species to sea-level rise and human development necessitate a modeling approach that can link species to the physical habitat features that will be altered by changes in sea level and human development. We used a Bayesian network framework to develop a model that links piping plover nest presence to the physical features of their nesting habitat on a Barrier Island that is impacted by sea-level rise and human development, using three years of data (1999, 2002, and 2008) from Assateague Island National Seashore in Maryland. Our model performance results showed that we were able to successfully predict nest presence given a wide range of physical conditions within the model's dataset. We found that model predictions were more successful when the ranges of physical conditions included in model development were varied rather than when those physical conditions were narrow. We also found that all model predictions had fewer false negatives (nests predicted to be absent when they were actually present in the dataset) than false positives (nests predicted to be present when they were actually absent in the dataset), indicating that our model correctly predicted nest presence better than nest absence. These results indicated that our approach of using a Bayesian network to link specific physical features to nest presence will be useful for modeling impacts of sea-level rise or human-related habitat change on Barrier Islands. We recommend that potential users of this method utilize multiple years of data that represent a wide range of physical conditions in model development, because the model performed less well when constructed using a narrow range of physical conditions. Further, given that there will always be some uncertainty in predictions of future physical habitat conditions related to sea-level rise and/or human development, predictive models will perform best when developed using multiple, varied years of data input.
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predictions of Barrier Island berm evolution in a time varying storm climatology
Journal of Geophysical Research, 2014Co-Authors: Nathaniel G Plant, James G Flocks, Hilary F Stockdon, Joseph W Long, Kristy K Guy, David M Thompson, Jamie M Cormier, Christopher G Smith, Jennifer L Miselis, Soupy P DalyanderAbstract:Low-lying Barrier Islands are ubiquitous features of the world's coastlines, and the processes responsible for their formation, maintenance, and destruction are related to the evolution of smaller, superimposed features including sand dunes, beach berms, and sandbars. The Barrier Island and its superimposed features interact with oceanographic forces (e.g., overwash) and exchange sediment with each other and other parts of the Barrier Island system. These interactions are modulated by changes in storminess. An opportunity to study these interactions resulted from the placement and subsequent evolution of a 2 m high sand berm constructed along the northern Chandeleur Islands, LA. We show that observed berm length evolution is well predicted by a model that was fit to the observations by estimating two parameters describing the rate of berm length change. The model evaluates the probability and duration of berm overwash to predict episodic berm erosion. A constant berm length change rate is also predicted that persists even when there is no overwash. The analysis is extended to a 16 year time series that includes both intraannual and interannual variability of overwash events. This analysis predicts that as many as 10 or as few as 1 day of overwash conditions would be expected each year. And an increase in berm elevation from 2 m to 3.5 m above mean sea level would reduce the expected frequency of overwash events from 4 to just 0.5 event-days per year. This approach can be applied to understanding Barrier Island and berm evolution at other locations using past and future storm climatologies.
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probabilistic prediction of Barrier Island response to hurricanes
Journal of Geophysical Research, 2012Co-Authors: Nathaniel G Plant, Hilary F StockdonAbstract:[1] Prediction of Barrier-Island response to hurricane attack is important for assessing the vulnerability of communities, infrastructure, habitat, and recreational assets to the impacts of storm surge, waves, and erosion. We have demonstrated that a conceptual model intended to make qualitative predictions of the type of beach response to storms (e.g., beach erosion, dune erosion, dune overwash, inundation) can be reformulated in a Bayesian network to make quantitative predictions of the morphologic response. In an application of this approach at Santa Rosa Island, FL, predicted dune-crest elevation changes in response to Hurricane Ivan explained about 20% to 30% of the observed variance. An extended Bayesian network based on the original conceptual model, which included dune elevations, storm surge, and swash, but with the addition of beach and dune widths as input variables, showed improved skill compared to the original model, explaining 70% of dune elevation change variance and about 60% of dune and shoreline position change variance. This probabilistic approach accurately represented prediction uncertainty (measured with the log likelihood ratio), and it outperformed the baseline prediction (i.e., the prior distribution based on the observations). Finally, sensitivity studies demonstrated that degrading the resolution of the Bayesian network or removing data from the calibration process reduced the skill of the predictions by 30% to 40%. The reduction in skill did not change conclusions regarding the relative importance of the input variables, and the extended model's skill always outperformed the original model.
Julie C Zinnert - One of the best experts on this subject based on the ideXlab platform.
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connectivity in coastal systems Barrier Island vegetation influences upland migration in a changing climate
Global Change Biology, 2019Co-Authors: Julie C Zinnert, Laura J Moore, Stephen M Via, Benjamin P Nettleton, Philip A Tuley, Jon Anthony StallinsAbstract:Due to their position at the land-sea interface, Barrier Islands are vulnerable to both oceanic and atmospheric climate change-related drivers. In response to relative sea-level rise, Barrier Islands tend to migrate landward via overwash processes which deposit sediment onto the backBarrier marsh, thus maintaining elevation above sea level. In this paper, we assess the importance of interior upland vegetation and sediment transport (from upland to marsh) on the movement of the marsh-upland boundary in a transgressive Barrier system along the mid-Atlantic Coast. We hypothesize that recent woody expansion is altering the rate of marsh to upland conversion. Using Landsat imagery over a 32 year time period (1984-2016), we quantify transitions between land cover (bare, grassland, woody vegetation, and marsh) and the marsh-upland boundary. We find that the Virginia Barrier Islands have both gains and losses in backBarrier marsh and upland, with 19% net loss from the system during the timeframe of the study and increased variance in marsh to upland conversion. This is consistent with recent work indicating a shift toward increasing rates of landward Barrier Island migration. Despite a net loss of upland area, macroclimatic winter warming resulted in 41% increase in woody vegetation in protected, low-elevation areas, introducing new ecological scenarios that increase resistance to sediment movement from upland to marsh. Our analysis demonstrates how the interplay between elevation and interior Island vegetative cover influences landward migration of the boundary between upland and marsh (a previously underappreciated indicator that an Island is migrating), and thus, the importance of including ecological processes in the Island interior into coastal modeling of Barrier Island migration and sediment movement across the Barrier landscape.
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Spatial–Temporal Dynamics in Barrier Island Upland Vegetation: The Overlooked Coastal Landscape
Ecosystems, 2016Co-Authors: Julie C Zinnert, Sheri A. Shiflett, Stephen Via, Spencer Bissett, Benjamin Dows, Paul Manley, Donald R. YoungAbstract:Barrier Islands provide the first line of defense against storms for millions of people living in coastal areas. Upland vegetation (that is, grassland, shrubland, and maritime forest) has received little attention, even though this land surface is most strongly affected by development pressures. We use remote-sensing analysis to assess state change on seven undeveloped Virginia Barrier Islands over 27 years (1984–2011) that are free from direct human influence. Our analysis highlights the spatial–temporally dynamic nature of Barrier Island upland land area and vegetation, with rapidly changing ecosystem states. Over the time period, upland vegetation was dramatically reduced by 29% whereas woody vegetation cover increased 40% across all Islands. Although conversions between sand, grassland, and woody vegetation were variable within each Island, three major patterns of vegetative land-cover change were apparent: overall loss of vegetative cover, frequent transitions between grass and woody cover, and gain in woody cover. These patterns are valuable for understanding natural evolution of Barrier Islands in response to sea-level rise. Evaluation of temporal dynamics in Barrier upland is needed to characterize underlying processes including Island resilience or chronic stress, and is a prerequisite to sustainable coastal management- and resilience-based planning, especially when implementing ecosystem-based solutions.
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spatial temporal dynamics in Barrier Island upland vegetation the overlooked coastal landscape
Ecosystems, 2016Co-Authors: Julie C Zinnert, Stephen M Via, Sheri A. Shiflett, Benjamin Dows, Spencer N Bissett, Paul V Manley, Donald R. YoungAbstract:Barrier Islands provide the first line of defense against storms for millions of people living in coastal areas. Upland vegetation (that is, grassland, shrubland, and maritime forest) has received little attention, even though this land surface is most strongly affected by development pressures. We use remote-sensing analysis to assess state change on seven undeveloped Virginia Barrier Islands over 27 years (1984–2011) that are free from direct human influence. Our analysis highlights the spatial–temporally dynamic nature of Barrier Island upland land area and vegetation, with rapidly changing ecosystem states. Over the time period, upland vegetation was dramatically reduced by 29% whereas woody vegetation cover increased 40% across all Islands. Although conversions between sand, grassland, and woody vegetation were variable within each Island, three major patterns of vegetative land-cover change were apparent: overall loss of vegetative cover, frequent transitions between grass and woody cover, and gain in woody cover. These patterns are valuable for understanding natural evolution of Barrier Islands in response to sea-level rise. Evaluation of temporal dynamics in Barrier upland is needed to characterize underlying processes including Island resilience or chronic stress, and is a prerequisite to sustainable coastal management- and resilience-based planning, especially when implementing ecosystem-based solutions.
Donald R. Young - One of the best experts on this subject based on the ideXlab platform.
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Spatial–Temporal Dynamics in Barrier Island Upland Vegetation: The Overlooked Coastal Landscape
Ecosystems, 2016Co-Authors: Julie C Zinnert, Sheri A. Shiflett, Stephen Via, Spencer Bissett, Benjamin Dows, Paul Manley, Donald R. YoungAbstract:Barrier Islands provide the first line of defense against storms for millions of people living in coastal areas. Upland vegetation (that is, grassland, shrubland, and maritime forest) has received little attention, even though this land surface is most strongly affected by development pressures. We use remote-sensing analysis to assess state change on seven undeveloped Virginia Barrier Islands over 27 years (1984–2011) that are free from direct human influence. Our analysis highlights the spatial–temporally dynamic nature of Barrier Island upland land area and vegetation, with rapidly changing ecosystem states. Over the time period, upland vegetation was dramatically reduced by 29% whereas woody vegetation cover increased 40% across all Islands. Although conversions between sand, grassland, and woody vegetation were variable within each Island, three major patterns of vegetative land-cover change were apparent: overall loss of vegetative cover, frequent transitions between grass and woody cover, and gain in woody cover. These patterns are valuable for understanding natural evolution of Barrier Islands in response to sea-level rise. Evaluation of temporal dynamics in Barrier upland is needed to characterize underlying processes including Island resilience or chronic stress, and is a prerequisite to sustainable coastal management- and resilience-based planning, especially when implementing ecosystem-based solutions.
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spatial temporal dynamics in Barrier Island upland vegetation the overlooked coastal landscape
Ecosystems, 2016Co-Authors: Julie C Zinnert, Stephen M Via, Sheri A. Shiflett, Benjamin Dows, Spencer N Bissett, Paul V Manley, Donald R. YoungAbstract:Barrier Islands provide the first line of defense against storms for millions of people living in coastal areas. Upland vegetation (that is, grassland, shrubland, and maritime forest) has received little attention, even though this land surface is most strongly affected by development pressures. We use remote-sensing analysis to assess state change on seven undeveloped Virginia Barrier Islands over 27 years (1984–2011) that are free from direct human influence. Our analysis highlights the spatial–temporally dynamic nature of Barrier Island upland land area and vegetation, with rapidly changing ecosystem states. Over the time period, upland vegetation was dramatically reduced by 29% whereas woody vegetation cover increased 40% across all Islands. Although conversions between sand, grassland, and woody vegetation were variable within each Island, three major patterns of vegetative land-cover change were apparent: overall loss of vegetative cover, frequent transitions between grass and woody cover, and gain in woody cover. These patterns are valuable for understanding natural evolution of Barrier Islands in response to sea-level rise. Evaluation of temporal dynamics in Barrier upland is needed to characterize underlying processes including Island resilience or chronic stress, and is a prerequisite to sustainable coastal management- and resilience-based planning, especially when implementing ecosystem-based solutions.
Jorge Lorenzo-trueba - One of the best experts on this subject based on the ideXlab platform.
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Simulating Barrier Island response to sea level rise with the Barrier Island and inlet environment (BRIE) model v1.0
Geoscientific Model Development, 2019Co-Authors: Jaap H Nienhuis, Jorge Lorenzo-truebaAbstract:Abstract. Barrier Islands are low-lying coastal landforms vulnerable to inundation and erosion by sea level rise. Despite their socioeconomic and ecological importance, their future morphodynamic response to sea level rise or other hazards is poorly understood. To tackle this knowledge gap, we outline and describe the Barrier Inlet Environment (BRIE) model that can simulate long-term Barrier morphodynamics. In addition to existing overwash and shoreface formulations, BRIE accounts for alongshore sediment transport, inlet dynamics, and flood–tidal delta deposition along Barrier Islands. Inlets within BRIE can open, close, migrate, merge with other inlets, and build flood–tidal delta deposits. Long-term simulations reveal complex emergent behavior of tidal inlets resulting from interactions with sea level rise and overwash. BRIE also includes a stratigraphic module, which demonstrates that Barrier dynamics under constant sea level rise rates can result in stratigraphic profiles composed of inlet fill, flood–tidal delta, and overwash deposits. In general, the BRIE model represents a process-based exploratory view of Barrier Island morphodynamics that can be used to investigate long-term risks of flooding and erosion in Barrier environments. For example, BRIE can simulate Barrier Island drowning in cases in which the imposed sea level rise rate is faster than the morphodynamic response of the Barrier Island.
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Simulating Barrier Island response to sea-level rise with the Barrier Island and inlet environment (BRIE) model v1.0
2019Co-Authors: Jaap H Nienhuis, Jorge Lorenzo-truebaAbstract:Abstract. Barrier Islands are low-lying coastal landforms vulnerable to inundation and erosion by sea-level rise. Despite their socio-economic and ecological importance, their morphodynamic response to sea-level rise or other hazards is poorly understood. To tackle this knowledge gap, we outline and describe the Barrier Inlet Environment (BRIE) model that can simulate long-term Barrier morphodynamics. In addition to existing overwash and shoreface formulations, BRIE accounts for alongshore sediment transport, inlet dynamics, and flood-tidal delta deposition along Barrier Islands. Inlets within BRIE can open, close, migrate, merge with other inlets, and build flood-tidal delta deposits. Long-term simulations reveal complex emergent behaviour of tidal inlets resulting from interactions with sea-level rise, and overwash. BRIE also includes a stratigraphic module, which demonstrates that Barrier dynamics under constant sea-level rise rates can result in stratigraphic profiles composed of inlet fill, flood-tidal delta and overwash deposits. In general, the BRIE model represents a process-based exploratory view of Barrier Island morphodynamics that can be used to investigate long-term risks of flooding and erosion in Barrier environments. For example, BRIE can simulate Barrier Island drowning in cases where the imposed sea-level rise rate is faster than the morphodynamic response of the Barrier Island.
