In Puerto Rico, a marathon effort builds to restore mangroves and dunes

In 2017, Hurricane Maria, a Category 5 storm, struck Puerto Rico. The hurricane dried up four basin mangrove forests in the island’s northeast, leaving behind an urgent need for restoration, according to Robert J. Mayer, a biology professor at the University of Puerto Rico at Aguadilla.

“Not having these ecosystems exposes communities and primary infrastructure to the pounding of waves generated by storms, putting the lives of hundreds of people and the integrity of their properties at risk in the face of future extreme climatic events,” said Mayer, who directs the university’s Vida Marina Center for Ecological Restoration and Coastal Conservation.

In collaboration with the University of Wisconsin–Madison, Mayer and student volunteers secured $500,000 in financial support from the National Fish and Wildlife Foundation (NFWF) for the restoration of Puerto Rico’s beleaguered northern mangrove forests, which grow along riverbanks or border salty lagoons.

Vida Marina will use the funds to restore a total of 59 hectares (146 acres) of mangrove basins between three coastal communities in the northeast, according to Mayer, including at Espinar Beach in Aguada, Jobos Beach and Secret Spot in Isabela, and the Finca Nolla Nature Reserve in Camuy.

“[The mangroves] are literally disintegrating by natural decay and there is no regeneration of vegetation except for some areas on their periphery,” Mayer said.

Although all the mangrove forests are important, Mayer said the one at Finca Nolla is especially vital, because it’s close to the community of Calle Abajo. Restoring it will protect and increase the resiliency of this community during future storms and hurricanes.

Mangroves in Puerto Rico aren’t just threatened by hurricanes. Most have been destroyed by dredging for agriculture and urban development, wastewater contamination, industrial pollution from power plants and oil spills, or the destruction of protective barrier ecosystems like sand dunes.

Since Hurricane Maria, the Coastal Research and Planning Institute of Puerto Rico found that the island’s beaches and water lines have migrated inland by 2 to 35 meters (7 to 115 feet). The institute also uncovered new patterns of erosion and accretion, the loss and gain of sediment, in several municipalities on the island, including in coastal ecosystems like mangroves and dunes.

Myriad benefits of mangroves

“In addition to protecting coasts, serving as nurseries for tropical oceans, and being temples of biodiversity, mangroves contribute [by acting] as natural filters for contaminants and sediments, resulting in clearer, better-quality water,” said Jorge Bauzá-Ortega, an environmental scientist with the San Juan Bay Estuary Program, which leads the mangrove reforestation efforts around the Puerto Rican capital.

According to Bauzá-Ortega, a 2012 study conducted on the island of New Caledonia in the Pacific Ocean demonstrated that mangroves can retain extremely toxic heavy metals in their roots, essentially locking them out of the wider environment.

“Up to 100 times more nickel, chromium and copper were detected in the mangroves than were dissolved in the adjacent water,” Bauzá-Ortega said. “And other studies have demonstrated that the mangrove forests also trap lead, cadmium and mercury.”

He likened the roots of mangroves to sediment traps, because they collect and store sediment that comes from the land. Mayer said mangroves are also highly efficient at storing carbon dioxide.

“It is also well known that mangroves sequester great quantities of carbon from the atmosphere making their conservation very important for tackling the current climate crisis,” he said.

Puerto Rico is home to all four mangorve species native to the Caribbean: red mangrove (Rhizophora mangle), white mangrove (Laguncularia racemosa), black mangrove (Avicennia germinans) and the button mangrove (Conocarpus erectus).

Restoring the dunes

It’s not just mangroves, however, that require restoration. Since it was founded in 2007, Vida Marina has also restored more than 16 kilometers (10 miles) of sand dunes in the municipalities of Arecibo, Camuy and Isabela.

“[Dunes are] the primary line of defense against the destructive force of strong waves, storm surge and tsunamis,” Mayer said. By restoring them, the organization also helps protect Puerto Rico’s sea turtles, which nest in the dunes.

An article in a 2007 report by the Coastal Zone Division of Puerto Rico’s Department of Environment and Natural Resources, pointed to an imbalance between the demand for sand and the available supply, due to Puerto Rico’s three-decade-long economic boom.

“This extraction [of sand] on a larger scale has created serious problems of erosion and saltwater intrusion on the coasts. Currently, many of these sand dunes have been quarried down toward the water table. The municipality of Isabela was one of the areas most affected by this activity; the most-developed dunes on the island were found there,” wrote the article’s author, Evelio J. Valeiras Miní.

Vida Marina began its dune restoration work in Isabela and later extended it to the dunes at the 39-hectare (97-acre) Finca Nolla Nature Reserve in Camuy, as well as other projects.

Restoration workers lay down rows of planks, made from recycled wooden pallets, to recreate the behavior of native plants that trap windblown sand. These structures are known as biomimicry matrices, and the technique is very effective in stabilizing the vegetation and the sand, according to José Juan Vera, an agronomist and member of Vida Marina. Eventually, the biomimicry matrices will help to form new dunes.

Coastal areas throughout the U.S., from Florida to South Carolina, and Michigan to New Jersey, have used the same biomimicry technique to restore their sand dunes, according to Mayer.

In addition to the financial support from the NFWF, Vida Marina also received funds from the Federal Emergency Management Agency (FEMA) for an unmanned aerial system that will allow them to create 3D maps to measure the area and volume of the sand in dune ecosystems. But more funding is needed, Mayer said.

“We still have over 100 sites on the primary dunes of the north coast of the island that need to be restored and [we] are constantly writing grant proposals to try to attract more funding to sustain our operation,” he said.

International collaboration

Vida Marina is also using its knowledge and work to build up a team of restoration experts.

“At this time, our main mission is to create a new generation of specialists in the ecological restoration of coastal environments. We are part of the Society for Ecological Restoration, an international organization that works on this concept,” said Mayer, who is certified in ecological restoration.

This year, Vida Marina will welcome international collaborators from Italy, the U.K. and Mexico.

“Not only are we restoring the coast in Puerto Rico, but we are also doing this with people who then have more exposure to nature and relaxation,” Mayer said. “They also learn skills surrounding the use of different tools and they gain knowledge.”

Just like the dunes, the work of Vida Marina grows along with the coastal ecosystems and the people involved.

“To us this work is a way of life,” Mayer said.

Banner image: Volunteers and staff members planting black mangrove in centers of dispersion that allow us to plant in lower water depths. This is part of an experiment being carried out by undergraduate research students from the UPR at Aguadilla. Image courtesy of Vida Marina, Center for Conservation and Ecological Restoration
University of Puerto Rico at Aguadilla.

Citation:

Marchand, C., Fernandez, J., Moreton, B., Landi, L., Lallier-Vergès, E., & Baltzer, F. (2012). The partitioning of transitional metals (FE, Mn, Ni, CR) in mangrove sediments downstream of a ferralitized ultramafic watershed (New Caledonia). Chemical Geology, 300-301, 70-80. doi:10.1016/j.chemgeo.2012.01.018