Sunday, February 23, 2025

Oyster reef restoration bonus: Mangroves!

Since 2018 my colleague Serge Thomas and I have been helping the City of Naples, Florida monitor three oyster restoration sites in Naples Bay. The project has been really successful in terms of oysters. They have colonized the constructed reefs at such high density that the original construction material (limestone rock and fossil shell) is now completely obscured by a spiky layer of living oysters. 




The concrete igloo things are called reef balls. At this site they are used as breakwaters to protect the rock pile reefs behind them from being eroded by boat wakes, which is a big problem for natural reefs in Naples Bay.

A bonus of the restoration is that the upper parts of many of the constructed reefs have been colonized by mangroves. Mangroves are tropical trees that grow in salt water and are helpful for protecting coastline from hurricanes, providing fish and wildlife habitat, and performing various other "ecosystem services" valuable to nature and humanity. 




Today I kayaked to two of the reefs with my undergraduate research students to count and measure the mangroves. Most were red mangroves (Rhizophora mangle), but we also saw black mangroves (Avicennia germinans), and white mangroves (Laguncularia racemosa). The site constructed last year had just small mangroves, freshly sprouted from the floating seedlings called propagules, while the site constructed seven years ago had substantial saplings with some over a meter high. 



Here my students are doing the official FGCU hand gesture, which is called "wings up" because our mascot is the bald eagle.

The students will analyze their data in more detail to try to figure out the patterns, like why some areas within the restoration site had tons of mangroves and others had relatively few. We hope this work will inform and inspire other restoration practitioners.

PS- If you have Florida waterfront, please let mangroves and other plants colonize and grow along the shoreline. In addition to providing myriad benefits to nature they will help protect your property from erosion.

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