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

Wolner, C. W. V.; Moore, Laura J.; Young, Donald R.; Brantley, Steven T.; Bissett, Spencer N.; McBride, Randolph A.

doi:10.1016/j.geomorph.2013.03.035

Cited by 72 publications

(86 citation statements)

References 30 publications

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“…In addition to storms, other factors such as a high water table, low sediment supply, grain size variability, development of shell lag and climatic conditions may also result in the suppression of the coalescing of coastal foredunes Russell, 2006, 2009;Wolner et al, 2013;Hoonhout and de Vries, 2016;Ruz and Hesp, 2014;Ruz et al, 2017a). Feedbacks between the wind, dune vegetation and sediment transport that are specific to hummocky dunes may also alter the rates of coalescing (Barrineau and Ellis, 2013;Gillies et al, 2014), such as the development of high wind velocity regions located adjacent to hummocky dune forms (Hesp and Smyth, 2017).…”

Section: Discussionmentioning

confidence: 99%

“…Low areas without dunes can remain low because of shell or coarse-grained lags, a high water table that causes plant stress, and/or climatic conditions such as cold temperatures prohibiting plant growth (e.g., Russell, 2006, 2009;Wolner et al, 2013;Ruz and Hesp, 2014;Ruz et al, 2017a). Godfrey (1977) hypothesized that barrier island orientation relative to the prevailing winds exerts a control on foredune morphology, with taller dunes occurring when winds blow directly onshore, perpendicular to the shoreline.…”

Section: Introductionmentioning

confidence: 99%

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Lateral vegetation growth rates exert control on coastal foredune hummockiness and coalescing time

2017

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Abstract. Coastal foredunes form along sandy, low-sloped coastlines and range in shape from continuous dune ridges to hummocky features, which are characterized by alongshore-variable dune crest elevations. Initially scattered dune-building plants and species that grow slowly in the lateral direction have been implicated as a cause of foredune "hummockiness". Our goal in this work is to explore how the initial configuration of vegetation and vegetation growth characteristics control the development of hummocky coastal dunes including the maximum hummockiness of a given dune field. We find that given sufficient time and absent external forcing, hummocky foredunes coalesce to form continuous dune ridges. Model results yield a predictive rule for the timescale of coalescing and the height of the coalesced dune that depends on initial plant dispersal and two parameters that control the lateral and vertical growth of vegetation, respectively. Our findings agree with previous observational and conceptual work -whether or not hummockiness will be maintained depends on the timescale of coalescing relative to the recurrence interval of high-water events that reset dune building in low areas between hummocks. Additionally, our model reproduces the observed tendency for foredunes to be hummocky along the southeast coast of the US where lateral vegetation growth rates are slower and thus coalescing times are likely longer.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Lateral vegetation growth rates exert control on coastal foredune hummockiness and coalescing time

2017

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“…Based on these previous studies, a 'high' island will develop if the frequency of storm events permits the recovery of dune building vegetation, while a low island will develop if frequent storms limit dune building vegetation (Stallins and Parker, 2003;Duran and Moore, 2013). The vegetation type is a response to changes in the amount of sediment partitioned between the nearshore and overwash, which suggests that a change in the frequency of storms relative to the rate of sediment exchange from the nearshore to the beachface (and ultimately the dune) may lead to a self-reinforcing cycle that ends with a 'low' island dominated by maintainer species that preserve flow flat topography (see Wolner et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

“…Compared to studies that document beach and dune erosion during storms, the rates and mechanisms of post-storm dune recovery have received relatively little attention in the literature -with notable exception for Olson (1958) (2013), Wolner et al (2013), and Lucas and Carter (2013). The majority of studies focus on erosion of the beach and dune, and the immediate recovery of the nearshore and beach profile following storms (Zeigler et al, 1959;Warnke et al, 1966;Katuna, 1991;Sexton and Hayes, 1991).…”

Section: Introductionmentioning

confidence: 99%

Post-storm beach and dune recovery: Implications for barrier island resilience

et al. 2015

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“…Specifically, it has been suggested that a feedback loop, subsequently termed the “maintainer feedback”, may contribute to the long-term maintenance of the low-elevation, frequently disturbed environment which characterizes Metompkin Island [5], [10]. The absence of dune-building due to the presence of S. patens enhances the probability of repeated disturbances [5].…”

Section: Discussionmentioning

confidence: 99%

Barrier Island Morphology and Sediment Characteristics Affect the Recovery of Dune Building Grasses following Storm-Induced Overwash

et al. 2014

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Barrier islands are complex and dynamic systems that provide critical ecosystem services to coastal populations. Stability of these systems is threatened by rising sea level and the potential for coastal storms to increase in frequency and intensity. Recovery of dune-building grasses following storms is an important process that promotes topographic heterogeneity and long-term stability of barrier islands, yet factors that drive dune recovery are poorly understood. We examined vegetation recovery in overwash zones on two geomorphically distinct (undisturbed vs. frequently overwashed) barrier islands on the Virginia coast, USA. We hypothesized that vegetation recovery in overwash zones would be driven primarily by environmental characteristics, especially elevation and beach width. We sampled species composition and environmental characteristics along a continuum of disturbance from active overwash zones to relict overwash zones and in adjacent undisturbed environments. We compared species assemblages along the disturbance chronosequence and between islands and we analyzed species composition data and environmental measurements with Canonical Correspondence Analysis to link community composition with environmental characteristics. Recovering and geomorphically stable dunes were dominated by Ammophila breviligulata Fernaud (Poaceae) on both islands while active overwash zones were dominated by Spartina patens (Aiton) Muhl. (Poaceae) on the frequently disturbed island and bare sand on the less disturbed island. Species composition was associated with environmental characteristics only on the frequently disturbed island (p = 0.005) where A. breviligulata was associated with higher elevation and greater beach width. Spartina patens, the second most abundant species, was associated with larger sediment grain size and greater sediment size distribution. On the less frequently disturbed island, time since disturbance was the only factor that affected community composition. Thus, factors driving the abundance of dune-building grasses and subsequent recovery of dunes varied between the two geomorphically distinct islands.

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

Cited by 72 publications

References 30 publications

Lateral vegetation growth rates exert control on coastal foredune hummockiness and coalescing time

Lateral vegetation growth rates exert control on coastal foredune hummockiness and coalescing time

Post-storm beach and dune recovery: Implications for barrier island resilience

Barrier Island Morphology and Sediment Characteristics Affect the Recovery of Dune Building Grasses following Storm-Induced Overwash

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