Grantee Research Project Results

Spartina alterniflora in a Changing Climate: Implications of Rising Temperatures for Salt Marsh Persistence

EPA Grant Number: F13B20238
Title: Spartina alterniflora in a Changing Climate: Implications of Rising Temperatures for Salt Marsh Persistence
Investigators: Crosby, Sarah Corman
Institution: Brown University
EPA Project Officer: Packard, Benjamin H
Project Period: September 4, 2014 through September 4, 2016
Project Amount: $84,000
RFA: STAR Graduate Fellowships (2013) RFA Text |  Recipients Lists
Research Category: Fellowship - Ecology , Academic Fellowships

Objective:

This research considers how the phenology and growth of an ecosystem engineer will respond to rising temperatures and how these changes will alter ecosystem function and persistence. It focuses on three sets of questions: (1) What patterns of growth occur along a temperature gradient in the salt marsh species Spartina alterniflora, and how will rising temperatures affect plant contributions to marsh elevation? (2) How does reproduction in S. alterniflora vary on multiple spatial scales, and how does flowering affect growth? (3) Where are salt marshes currently keeping pace with sea level rise, and how might that change under the sea level rise rates predicted for the future?

Approach:

To answer the first question about growth and temperature, the project uses field surveys, a transplant experiment and a greenhouse common garden experiment with marshes and plants from along a latitudinal gradient on the U.S. East coast. The second question is being addressed with multiscale field surveys, biomass collection and field and laboratory experiments. A literature review and meta-analysis will explore marsh elevation change and identify where marshes are keeping pace and where they are likely to keep pace in the future.

Expected Results:

Plasticity in growth is expected to occur in response to warming. As a result of these shifts, drowning is likely to lead to greater marsh loss. It also is expected that flowering phenology cues the timing of biomass allocation. Within-marsh patterns of timing and density of flowering will likely show an effect of temperature on marsh plant seed output. Finally, this work is likely to demonstrate that the majority of currently existing salt marshes will not be able to keep pace with projected rates of sea level rise.

Potential to Further Environmental/Human Health Protection

Salt marshes are an invaluable part of sustainable, livable communities on U.S. coasts, providing ecological and economic benefits far beyond the shoreline, such as food provision, water filtration and protection from storms. Marsh drowning due to insufficient elevation is possible with climate change, but the rate and likelihood are unclear. This research will meaningfully expand understanding of these issues. S. alterniflora is a foundation species, critical to marsh persistence. Generating data on temperature effects and the current status of marsh elevation gain will improve the ability to select areas for protected status and manage expectations of future services on local and regional scales.

Supplemental Keywords:

phenology, salt marsh, sea level rise

Progress and Final Reports:

2015

Final