Investigating dune-building feedback at the plant level: Insights from a multispecies field experiment

Coastal foredunes provide the first line of defense against rising sea levels and storm surge and for this reason there is increasing interest in understanding and modeling foredune formation and post-storm recovery. However, there is limited observational data available to provide empirical guidance for the development of model parameterizations. To provide guidance for improved representation of dune grass growth in models, we conducted a two-year multi-species transplant experiment on Hog Island, VA, U.S.A. and measured the dependence of plant growth on elevation and distance from the shoreline, as well as the relationship between plant growth and sand accumulation. We tracked total leaf growth (length) and aboveground leaf length and found that Ammophila breviligulata (American beachgrass) and Uniola paniculata (sea oats) grew more than Spartina patens (saltmeadow cordgrass) by a factor of 15% (though not statistically significant) and 45%, respectively. Our results also suggest a range of basal/frontal area ratios (an important model parameter) from 0.5-1 and a strong correlation between transplant growth and total sand deposition for all species at the scale of two years, but not over shorter temporal scales. Distance from the shoreline and elevation had no effect on transplant growth rate but did have an effect on survival. Based on transplant survival, the seaward limit of vegetation at the end of the experiment was approximately 30 m from the MHWL and at an elevation of 1.43 m, corresponding to inundation less than 7.5% of the time according to total water level calculations. Results from this experiment provide evidence for the dune-building capacity of all three species, suggesting S. patens is not a maintainer species, as previously thought, but rather a moderate dune builder even though its growth is less stimulated by sand deposition than A. breviligulata and U. paniculata

Leadership in working with communities and adaptation to the impacts of sea-level rise: interaction among federal agencies, NGO’s, scientists, and community leaders

The emerging concern regarding impacts of sea-level rise amongst the U.S. coastal national parks is the impetus for reaching beyond the jurisdictional limits of the parks to engage the adjacent communities in identifying natural and cultural resources at risk and adaptation strategies to address the concerns. In the first meeting of its kind in the Northeast, the Gateway National Recreation Area of the National Park Service and NOAA’s Jacques Cousteau National Estuarine Research Reserve involved seven communities in a workshop on environmental changes affecting the Raritan Bay shoreline. The thrust was to describe the background science on sea-level rise in the immediate area, the dimensions and directions of ecological adjustments in the Park, the impacts to existing infrastructure, and the possible responses in a management context. Scientists from Rutgers University, personnel from the NOAA Coastal Services Center, the local county GIS office, and two NGOs provided assistance and information. The goal was to use the National Park as an example of an approach to understand the conditions that are occurring at the local scale and to identify resources available to the municipal residents and officials. It was an instance of leadership by example in a non-competitive setting

Barrier Islands: Coupling anthropogenic stability with ecological sustainability

Barrier islands provide a host of critical ecosystem services to heavily populated coastal regions of the world, yet they are quite vulnerable to ongoing sea level rise and a potential increase in the frequency and intensity of oceanic storms. These islands are being degraded at an alarming rate, in part because of anthropogenic attempts at stabilization. In this article, we outline a possible sustainability strategy that incorporates the natural degree of substrate instability on these sedimentary landscapes. We recommend placing the focus for managing barrier islands on maintaining ecosystem function and process development rather than emphasizing barrier islands as structural impediments to wave and storm energy. © 2010 the Coastal Education & Research Foundation (CERF)