Do Prescribed Burns of Phragmites Australis Increase Denitrification and Carbon Sequestration? - NERRS/NSC(NERRS Science Collaborative)

Coastal managers in Delaware examined whether biochar input from prescribed burns restores ecosystem services after removal of Phragmites australis, an invasive grass species.

The Project

Phragmites australis is an invasive grass species that affects many marshes along the U.S east coast, often displacing native grasses. Removing Phragmites has been a decades-long management goal as managers seek to restore native high marsh habitat and ecosystem functions and services. Phragmites removal and restoration efforts have proven beneficial for habitat and biodiversity. However, its removal has potentially negative impacts on water quality and carbon storage, as Phragmites stores nitrogen and phosphorus and accumulates organic carbon more effectively than native marsh vegetation. Tidal wetland managers are left with uncertainties about these tradeoffs of Phragmites removal and their implications for achieving marsh restoration goals. A potential approach for managing tradeoffs associated with Phragmites removal is to use prescribed fire. While prescribed fire is a common method for vegetation removal, there has been limited research on the biogeochemical benefits provided by burned biomass or "biochar". Biochar may increase soil nitrogen removal and carbon and phosphorus storage, which can help to counteract losses in ecosystem services due to Phragmites removal.

Collaborating with regional coastal managers, this project team compared salt marshes with and without a history of prescribed burns at Delaware National Estuarine Research Reserve and area marshes to better quantify how fire impacts marshes and their ecosystem services. The team collected and analyzed salt marsh sediment cores at multiple sites and found that the marshes that were more frequently burned had enhanced carbon storage. They also used biochar amendments to learn more about other biogeochemical metrics, like denitrification potential and phosphorus storage, and found that biochar's impact on these metrics were limited.

The project convened an Advisory Committee that held productive discussions on current and potential Phragmites management practices, prescribed burn practices, and climate-adaptive decision-making procedures, in the context of the project's findings. These conversations helped inform a comprehensive report on the impacts of prescribed burns on tidal marsh ecosystem services. This report will allow for easier transfer of knowledge among the project's partners, including Delaware NERR, Delaware Natural Resources and Environmental Control, U.S. Fish and Wildlife Service, Center for the Inland Bays, Partnership for the Delaware Estuary, and Delaware Wild Lands.

The Impact

Developed a better understanding of how prescribed burns impact a larger suite of physical, biogeochemical, recreational, cultural, and socio-economic ecosystem services.

Facilitated knowledge sharing at an immersive workshop that brought together over 90 coastal managers and researchers.

Identified new and emerging management questions; for example, "What protocol leads to the most successful herbicide-burn management of Phragmites" and "What role do site-specific factors play in marsh management?"

Project and Technical Lead

Andrew Wozniak, University of Delaware, awozniak@udel.edu

Collaborative Lead

Mollie Yacano, Delaware Department of Natural Resources and Environmental Control, mollie.yacano@delaware.gov

Collaborative Team Member

Lynne Pusey, Delaware Department of Natural Resources and Environmental Control, lynne.pusey@delaware.gov

Partners:

Delaware Natural Resources and Environmental Control; U.S. Fish and Wildlife Service; Center for the Inland Bays; Partnership for the Delaware Estuary; Delaware Wild Lands

The distributor does not assume liability.

None

Cite this dataset when used as a source: NOAA retains the right to analyze, synthesize and publish summaries of the NERRS/NSC data. The NERRS/NSC retains the right to be fully credited for having collected and process the data. Following academic courtesy standards, the NERR site where the data were collected should be contacted and fully acknowledged in any subsequent publications in which any part of the data are used. The data enclosed within this package/transmission are only as accurate as the quality assurance and quality control procedures that are described in the associated metadata reporting statement allow. The user bears all responsibility for its subsequent use/misuse in any further analyses or comparisons. The Federal government does not assume liability to the Recipient or third persons, nor will the Federal government reimburse or indemnify the Recipient for its liability due to any losses resulting in any way from the use of this data. Requested citation format: NOAA National Estuarine Research Reserve System (NERRS) Science Collaborative(NSC).

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This information is detailed within the project links.

This information is detailed within the project links.