2010 Progress Report: Beach Grass Invasions and Coastal Flood Protection: Forecasting the Effects of Climate Change on Coastal Vulnerability

EPA Grant Number: R833836
Title: Beach Grass Invasions and Coastal Flood Protection: Forecasting the Effects of Climate Change on Coastal Vulnerability
Investigators: Hacker, Sally , Seabloom, Eric , Ruggiero, Peter
Current Investigators: Seabloom, Eric , Ruggiero, Peter , Hacker, Sally
Institution: Oregon State University
EPA Project Officer: Packard, Benjamin H
Project Period: July 1, 2008 through June 30, 2012 (Extended to June 30, 2013)
Project Period Covered by this Report: July 1, 2009 through June 30,2010
Project Amount: $599,980
RFA: Ecological Impacts from the Interactions of Climate Change, Land Use Change and Invasive Species: A Joint Research Solicitation - EPA, USDA (2007) RFA Text |  Recipients Lists
Research Category: Global Climate Change , Aquatic Ecosystems , Ecosystems , Climate Change

Objective:

Increased storm severity and sea-level-rise resulting from climate change have greatly elevated the risk of coastal communities. These risks have been exacerbated by alterations to coastal ecosystems and the introduction of non-native species. In the Pacific Northwest of the US, coastal dunes protect about half of the coastline, and our initial results suggest that increases in wave height and sea level rise could increase the frequency with which waves overtop and erode dunes. Intentional planting of non-native grasses may have initially increased coastal protection from flooding by building tall foredunes parallel to the shoreline. However, an unintentional second invasion appears to be decreasing foredune height thereby increasing risk exposure. In addition, many agencies are removing beach grasses to restore habitat for imperilled species. The effects of these conservation actions on flooding risk are unknown. Managers of west coast dune systems are faced with an apparent conundrum. Climate change is increasing the need for the protection services of grass dominated coastal dunes, but conservation mandates the removal of these invasive grasses to favor recovery of threatened and endangered species. Furthermore, the uncontrolled invasion by the second grass, A. breviligulata, is associated with declines in dune height and biodiversity. Despite the conflicting values of coastal protection and conservation, neither invasive species dynamics nor coastal protective values have been quantified under future invasion and climate change scenarios. Here we propose research to address three fundamental objectives (1) Determine the relationship between climate change and beach grass invasion, (2) Determine the effects of non-native beach grass invasion on coastal vulnerability, and (3) Determine if conservation management alters coastal vulnerability to flooding under a range of climate change, invasion and management scenarios.

Progress Summary:

We have assembled a large dataset that includes shoreline change, dune geomorphology, and vegetation data necessary to understand the interaction between sand supply, dune grass invader, and the effects on foredune geomorphology (Objective 1). We have collected shoreline change, duen geomorphology, and vegetation data along 77 transects surveyed from Grays Harbor, Washington, to Bandon, Oregon. Analysis shows that dune geomorphology is the result of both sand supply and dune grass species - sites with high sand supply and Ammophila breviligulata as the dominant invader feature shorter and wider dunes compared to sites that have low sand supply and A. arenaria as the dominant invader. We have begun experiments to look at the mechanisms of this interaction. To assess vulnerability to storm waves and sea level we have applied total water level (TWL) models developed by Ruggiero to our dune geomorphology measurements (Objective 2). Our calculations thus far suggest that shorter dunes dominated by A. breviligulata are more vulnerable to overtopping than taller dunes dominated by A. arenaria. We are in the process of resolving the results of different models to understand how foredunes dominated by either species respond to erosion. To assess vulnerability of dunes to various climate change, invasion, and management scenarios, we have developed a number of realistic climate change scenarios relevant to foredune flooding risk (Objective 3). These include sea level rise and increases in wave heights. We have begun to apply these scenarios to current grass invasion dynamics, but in addition, to projected invasion scenarios including the situation in which A. breviligulata dominates along the entire Oregon coast. We have not started the work on applying these models to different management scenarios. Finally, one of us (Hacker) has worked as part of a collaborative group that is considering the functions and services provided by estuarine and coastal ecosystems. The knowledge of dunes gained from this grant has contributed substantially to this broader, international research and we have a number of papers published from this group.

Future Activities:

We will continue to collect more data along our transects, maintain our experiments, apply models to our data, write papers, and make presentations at meetings.


Journal Articles on this Report : 6 Displayed | Download in RIS Format

Other project views: All 55 publications 19 publications in selected types All 17 journal articles
Type Citation Project Document Sources
Journal Article Barbier EB, Koch EW, Silliman BR, Hacker SD, Wolanski E, Primavera JH, Granek EF, Polasky S, Aswani S, Cramer LA, Stoms DM, Kennedy CJ, Bael D, Kappel C, Perillo GME, Reed DJ. Vegetation's role in coastal protection:response. Science 2008;320:176-177. R833836 (2010)
R833836 (2011)
R833836 (2012)
R833836 (Final)
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  • Journal Article Barbier EB, Koch EW, Silliman BR, Hacker SD, Wolanski E, Primavera J, Granek EF, Polasky S, Aswani S, Cramer LA, Stoms DM, Kennedy CJ, Bael D, Kappel CV, Perillo GME, Reed DJ. Coastal ecosystem-based management with nonlinear ecological functions and values. Science 2008;319(5861):321-323. R833836 (2010)
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  • Journal Article Barbier EB, Hacker SD, Kennedy C, Koch EW, Stier AC, Silliman BR. The value of estuarine and coastal ecosystem services. Ecological Monographs 2011;81(2):169-193. R833836 (2010)
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  • Journal Article Hacker SD, Zarnetske P, Seabloom E, Ruggiero P, Mull J, Gerrity S, Jones C. Subtle differences in two non-native congeneric beach grasses significantly affect their colonization, spread, and impact. Oikos 2012;121(1):138-148. R833836 (2010)
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  • Journal Article Koch EW, Barbier EB, Silliman BR, Reed DJ, Perillo GME, Hacker SD, Granek EF, Primavera JH, Muthiga N, Polasky S, Halpern BS, Kennedy CJ, Kappel CV, Wolanski E. Non-linearity in ecosystem services: temporal and spatial variability in coastal protection. Frontiers in Ecology and the Environment 2009;7(1):29-37. R833836 (2010)
    R833836 (2011)
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  • Journal Article Zarnetske PL, Seabloom EW, Hacker SD. Non-target effects of invasive species management:beach grass, birds, and bulldozers in coastal dunes. Ecosphere 2010;1(5):1-20. R833836 (2010)
    R833836 (2011)
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  • Supplemental Keywords:

    Global climate, invasion, dune geomorphology, foredune, coastal protection, risk assessment, beach grasses, Ammophila arenaria, Ammophila breviligulata, community structure, shoreline change, ecosystem services, climate models, total water level models, management;, RFA, Scientific Discipline, Air, climate change, Air Pollution Effects, Environmental Monitoring, Ecological Risk Assessment, Atmosphere, anthropogenic stress, biodiversity, environmental stressors, coastal ecosystems, ecosystem impacts, landscape characterization, climate variability, Global Climate Change

    Relevant Websites:

    Sally Hacker: http://www.science.oregonstate.edu/~hackers/Site/Homepage.html­ Exit

    Progress and Final Reports:

    Original Abstract
  • 2009 Progress Report
  • 2011 Progress Report
  • 2012 Progress Report
  • Final Report