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St. Bernard Parish Enlists Black Mangroves to Combat Coastal Erosion

In April, St. Bernard Parish Government’s (SBPG) Coastal Division and volunteers from multiple agencies and institutions planted 1,000 black mangrove trees in the eastern Biloxi Marsh. This is the first project of the St. Bernard Parish Black Mangrove Planting Program, a collaboration between the SPBG Coastal Division and several schools and organizations, to address coastal erosion issues.

“What I love about this project is that the use of black mangroves was suggested to us by some fly fisherman who do charters in the proposed site area. We took their suggestion and ran with it,” John Lane, SPBG Coastal Division executive director said.

Jerry Graves, coastal advisor for the SPBG Coastal Division, admitted there was some initial skepticism.

“We began visiting the Biloxi Marsh in search of existing healthy black mangrove stands,” Graves said. “After locating them on the eastern outlying islands of the Biloxi Marsh, we began reaching out to black mangrove researchers throughout the state. Researchers were surprised to learn that black mangroves were able to survive at the latitudinal coordinates we were finding them.”

The black mangrove – a native plant species that can grow up to nine feet and is typically found in tropical climates – has seen steady expansion across coastal Louisiana since 1990. While mangroves are found in warmer climates, the black mangrove is the most tolerant to colder conditions.

The northern expansion of black mangroves in St. Bernard Parish immediately piqued everyone’s interest, Graves said. The SBPG Coastal Division then took the next steps to initiate a black mangrove planting program by establishing an informal partnership with the University of Louisiana at Lafayette, Nicholls State University, the LSU AgCenter, Chalmette High School, the Louisiana Department of Agriculture and Forestry and local business and organizations like Low Tide Charters, the Save Louisiana Coalition, and the Meraux Foundation.

According the St. Bernard Parish Black Mangrove Planting Program’s executive summary, the project’s focus is to the increase black mangrove habitat in St. Bernard Parish for the purpose of: restoring/creating essential fish habitat; increasing the overall health and resilience of the coastal ecosystem; and reducing risk to life and property in the region by enhancing natural storm surge defenses. The planting program consists of four primary components: (1) propagule collection and cultivation; (2) greenhouse management; (3) strategic site selection and planting; and (4) monitoring.

“This is the perfect project where the entire community can get involved, get their hands dirty, have fun and make a difference,” Lane said.

Dominique Seibert – an Extension agent with Louisiana Sea Grant and the LSU AgCenter in St. Bernard, and volunteer at the first planting event – echoed those sentiments.

“It’s a wonderful experience to be part of an ongoing coastal restoration project that includes St. Bernard Parish government, high school students, and members of the community. Projects like these have multiple benefits, and with our vanishing coastline, this community has really come together to make a difference,” Seibert said.

Black mangroves perform a number of essential functions in coastal wetlands, including providing nursery and nesting habitats for various species. However, it is the root system of the plant that led the SPBG Coastal

Division to consider black mangroves for its first line of defense in tackling land loss. The extensive root system has the potential to strengthen and sustain the shoreline, and in turn, protect life property and infrastructure.

“We have estimated that every 1,500 black mangroves planted can protect one linear mile of shoreline. Additionally, mature black mangroves will naturally release approximately 500 propagules each year,” Graves said. “We are confident that barring any major hurricanes or significant climactic changes, the program will provide a substantial nature-based defense to coastal erosion and land loss in the targeted areas.”