Salinity and the small-scale distribution of three barrier island shrubs

1994 ◽  
Vol 72 (9) ◽  
pp. 1365-1372 ◽  
Author(s):  
Donald R. Young ◽  
David L. Erickson ◽  
Shawn W. Semones
Keyword(s):  
Water Relations ◽  
Barrier Island ◽  
Barrier Islands ◽  
Small Scale ◽  
Similar Response ◽  
Groundwater Salinity ◽  
Baccharis Halimifolia ◽  
Myrica Cerifera ◽  
Interspecific Differences ◽  
Iva Frutescens

The importance of salinity to small-scale distribution patterns was examined for three shrubs common on barrier islands of the southeastern United States. Field measurements focused on the salt marsh – upland interface zone on Hog Island, Virginia, where Myrica cerifera, Baccharis halimifolia, and Iva frutescens form distinct distributional zones. Although considerable variation in salinity occurred throughout the growth season (June through October), total soil chlorides and groundwater salinity were lowest for M. cerifera, intermediate for B. halimifolia, and highest for I. frutescens. All three species showed similar diurnal and seasonal patterns in stomatal conductance and leaf xylem pressure potential, despite the differences in salinity. However, a laboratory experiment revealed interspecific differences in water relations when the three shrubs were exposed to identical salinity regimes. The field data and water relations experiment indicated M. cerifera is least tolerant to salinity, I. frutescens is most tolerant, and B. halimifolia is intermediate. Seed germination experiments revealed a similar response, except that B. halimifolia was more sensitive to salinity than M. cerifera. The interspecific differences in soil and groundwater salinity, along with the physiological response differences, indicated that salinity may be one of the major environmental factors influencing zonation among the three shrubs; however, the absence of I. frutescens and B. halimifolia in low salinity areas implied that other factors also influence zonation patterns on barrier islands. Key words: Baccharis halimifolia, Iva frutescens, Myrica cerifera, barrier island, salinity tolerance, shrub.

Small-scale distribution and salinity response of Juniperus virginiana on an Atlantic Coast barrier island

1997 ◽  
Vol 75 (1) ◽  
pp. 77-85 ◽  
Author(s):  
David W. Martin ◽  
Donald R. Young
Keyword(s):  
Ground Water ◽  
Atlantic Coast ◽  
Barrier Island ◽  
Distribution Patterns ◽  
Small Scale ◽  
Juniperus Virginiana ◽  
Plant Responses ◽  
Rooting Zone ◽  
Red Cedar ◽  
Salinity Response

A field and laboratory study examined the hypothesis that the small-scale distribution pattern of Juniperus virginiana on barrier islands is related to salinity patterns and plant responses to salinity. Temporal (May – October) and spatial variability in ground water availability, ground water salinity, and total soil chlorides were quantified across a Virginia barrier island. Groundwater depth and salinity increased throughout the summer; microtopographic position and location on the island also affected soil salinities. Highest salinities occurred near the ocean side beach and bay side marsh, as well as in low lying swales that flood during extreme high tides or storms. Median rooting zone chloride level for J. virginiana was 54 μg/g. In contrast, laboratory germination and growth studies indicated that J. virginiana was significantly affected only at high salinity levels (1000 and 1400 μg/g), suggesting that salinity is not the only factor regulating small-scale distribution patterns. The broad tolerance to salinity may account for the abundance of J. virginiana in coastal environments. Key words: barrier island, eastern red cedar, Juniperus virginiana, salinity response, water relations.

scholarly journals Modeling Barrier Island Habitats Using Landscape Position Information

2019 ◽  
Vol 11 (8) ◽  
pp. 976
Author(s):  
Nicholas M. Enwright ◽  
Lei Wang ◽  
Hongqing Wang ◽  
Michael J. Osland ◽  
Laura C. Feher ◽  
...  
Keyword(s):  
Machine Learning ◽  
Random Forest ◽  
Nearest Neighbor ◽  
Learning Algorithms ◽  
Barrier Island ◽  
Barrier Islands ◽  
Machine Learning Algorithms ◽  
Landscape Position ◽  
K Nearest Neighbor ◽  
Island Habitats

Barrier islands are dynamic environments because of their position along the marine–estuarine interface. Geomorphology influences habitat distribution on barrier islands by regulating exposure to harsh abiotic conditions. Researchers have identified linkages between habitat and landscape position, such as elevation and distance from shore, yet these linkages have not been fully leveraged to develop predictive models. Our aim was to evaluate the performance of commonly used machine learning algorithms, including K-nearest neighbor, support vector machine, and random forest, for predicting barrier island habitats using landscape position for Dauphin Island, Alabama, USA. Landscape position predictors were extracted from topobathymetric data. Models were developed for three tidal zones: subtidal, intertidal, and supratidal/upland. We used a contemporary habitat map to identify landscape position linkages for habitats, such as beach, dune, woody vegetation, and marsh. Deterministic accuracy, fuzzy accuracy, and hindcasting were used for validation. The random forest algorithm performed best for intertidal and supratidal/upland habitats, while the K-nearest neighbor algorithm performed best for subtidal habitats. A posteriori application of expert rules based on theoretical understanding of barrier island habitats enhanced model results. For the contemporary model, deterministic overall accuracy was nearly 70%, and fuzzy overall accuracy was over 80%. For the hindcast model, deterministic overall accuracy was nearly 80%, and fuzzy overall accuracy was over 90%. We found machine learning algorithms were well-suited for predicting barrier island habitats using landscape position. Our model framework could be coupled with hydrodynamic geomorphologic models for forecasting habitats with accelerated sea-level rise, simulated storms, and restoration actions.

scholarly journals Simulating barrier island response to sea level rise with the barrier island and inlet environment (BRIE) model v1.0

2019 ◽  
Vol 12 (9) ◽  
pp. 4013-4030 ◽  
Author(s):  
Jaap H. Nienhuis ◽  
Jorge Lorenzo-Trueba
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Barrier Island ◽  
Barrier Islands ◽  
Emergent Behavior ◽  
Tidal Inlets ◽  
Rise Rate ◽  
Ecological Importance ◽  
Alongshore Sediment Transport

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.

scholarly journals Modeling the Evolution of a Freshwater Lens under Highly Dynamic Conditions on a Currently Developing Barrier Island

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Tobias Holt ◽  
Janek Greskowiak ◽  
Stephan L. Seibert ◽  
Gudrun Massmann
Keyword(s):  
Barrier Island ◽  
Coastal Protection ◽  
Groundwater Salinity ◽  
Field Observations ◽  
Salinity Distribution ◽  
Freshwater Lens ◽  
Lens Formation ◽  
The Impact ◽  
Freshwater Lenses ◽  
Dune Area

The drinking water supply on barrier islands largely depends on freshwater lenses, which are also highly relevant for island ecosystems. The freshwater lens presented in this study is currently developing (since the 1970s) below the very young eastern part of the North Sea barrier island Spiekeroog, the so-called “Ostplate.” Due to the absence of coastal protection measures, formation, shape, and extent of the freshwater lens below the Ostplate are unaffected by human activities but exposed to dynamic changes, e.g., geomorphological variations and storm tides. The main aim of this paper was to reconstruct the evolution of the freshwater lens over several decades in order to explain the present-day groundwater salinity distribution. In addition, the study assessed the impact of geomorphological variations and storm tides on the freshwater lens formation. Detailed field observations were combined with a transient 2-D density-dependent modeling approach. Both field observations and simulations show an asymmetric freshwater lens after ~42 years of formation, whereby the horizontal extent is limited by the elevated dune area. The simulations indicate that the young freshwater lens has nearly reached quasi-steady-state conditions mainly due to the continuous mixing with seawater infiltrating during storm tides, which inhibits further growth of the freshwater lens on the narrow island. The findings further show that (i) a neglection of storm tides results in a significant overestimation of the freshwater lens extent, and (ii) the modeled present groundwater salinity distribution and shape of the freshwater lens are predominantly determined by the position and extent of the elevated dune area at the past ~20 years. Hence, annual storm tides have to be directly implemented into numerical models to explain the groundwater salinity distribution and the extent of young freshwater lenses located in highly dynamic tidal environments.

VAM association in the shrub Myrica cerifera on a Virginia, USA barrier island

Mycorrhiza ◽  
1995 ◽  
Vol 5 (6) ◽  
pp. 423-429 ◽  
Author(s):  
Shawn W. Semones ◽  
Donald R. Young
Keyword(s):  
Barrier Island ◽  
Myrica Cerifera

scholarly journals Statistical modeling of the long-range-dependent structure of barrier island framework geology and surface geomorphology

2018 ◽  
Vol 6 (2) ◽  
pp. 431-450 ◽  
Author(s):  
Bradley A. Weymer ◽  
Phillipe Wernette ◽  
Mark E. Everett ◽  
Chris Houser
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Long Range ◽  
Moving Average ◽  
Quantitative Measure ◽  
Barrier Island ◽  
Barrier Islands ◽  
Wave Number ◽  
Statistical Parameters ◽  
Padre Island

Abstract. Shorelines exhibit long-range dependence (LRD) and have been shown in some environments to be described in the wave number domain by a power-law characteristic of scale independence. Recent evidence suggests that the geomorphology of barrier islands can, however, exhibit scale dependence as a result of systematic variations in the underlying framework geology. The LRD of framework geology, which influences island geomorphology and its response to storms and sea level rise, has not been previously examined. Electromagnetic induction (EMI) surveys conducted along Padre Island National Seashore (PAIS), Texas, United States, reveal that the EMI apparent conductivity (σa) signal and, by inference, the framework geology exhibits LRD at scales of up to 101 to 102 km. Our study demonstrates the utility of describing EMI σa and lidar spatial series by a fractional autoregressive integrated moving average (ARIMA) process that specifically models LRD. This method offers a robust and compact way of quantifying the geological variations along a barrier island shoreline using three statistical parameters (p, d, q). We discuss how ARIMA models that use a single parameter d provide a quantitative measure for determining free and forced barrier island evolutionary behavior across different scales. Statistical analyses at regional, intermediate, and local scales suggest that the geologic framework within an area of paleo-channels exhibits a first-order control on dune height. The exchange of sediment amongst nearshore, beach, and dune in areas outside this region are scale independent, implying that barrier islands like PAIS exhibit a combination of free and forced behaviors that affect the response of the island to sea level rise.

Nassella pulchra Survival and Water Relations Depend More on Site Productivity Than on Small-Scale Disturbance

2007 ◽  
Vol 15 (2) ◽  
pp. 177-178 ◽  
Author(s):  
Keith Lombardo ◽  
Jeffrey S. Fehmi ◽  
Kevin J. Rice ◽  
Emilio A. Laca
Keyword(s):  
Water Relations ◽  
Small Scale ◽  
Site Productivity ◽  
Nassella Pulchra

Ecomorphodynamic feedbacks and barrier island response to disturbance: Insights from the Virginia Barrier Islands, Mid-Atlantic Bight, USA

Geomorphology ◽  
2013 ◽  
Vol 199 ◽  
pp. 115-128 ◽  
Author(s):  
Catherine W.V. Wolner ◽  
Laura J. Moore ◽  
Donald R. Young ◽  
Steven T. Brantley ◽  
Spencer N. Bissett ◽  
...  
Keyword(s):  
Barrier Island ◽  
Barrier Islands
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