When mangrove planting hits the headlines, people tend to rejoice, as it brings a sense of hope. Efforts to conduct this activity shouldn't be overlooked; they are mostly well-intentioned after all. But are we planting mangroves in the right location? More importantly, are we planting the correct species of mangroves?
Dr. Jurgenne Primavera, chief mangrove scientific advisor at the Zoological Society of London, offers valuable insights on approaching mangrove planting with science. She began her coastal greenbelt advocacy in 1993 with a paper published in Reviews in Fisheries Science.
Science-based mangrove planting
According to Dr. Primavera, mangrove planting has become a popular activity conducted by governments and NGOs alike, but it needs to be science-based. “Plant the right species along the seafront, piapi/Avicennia marina and pagatpat/ Sonneratia alba, and not the convenient but ecologically incorrect bakhaw/Rhizophora species,” she said.
Apart from helping prevent chronic flooding and erosion, mangrove forests store up to five times more carbon than other types of forests — crucial in the fight against climate change. But we must plant them in the correct spot.
“Plant mangroves in the right location. In the middle to upper intertidal zone, and not the lower intertidal to subtidal, most especially not on seagrass beds,” she added.
100-meter coastal greenbelt
The Philippines averages 20 typhoons yearly, which calls for greenbelts of mangrove and beach forest trees to prevent death tolls and infrastructure damage.
A 2012 meta-analysis of several mangrove studies worldwide concluded that "a 100-meter wide band of mangrove and beach trees will protect coastal communities by absorbing wave energy (storm surge) by up to 60 percent.” This is one of the reasons why the National Coastal Greenbelt bill in the country was urged in July 2024, calling for authorities to pass it urgently.
A paper published in Science, the world's top scientific journal, also reviewed dozens of mangrove research. It found that "the highest economic value of all uses combined (e.g., coastal protection, aquaculture, and fisheries) can be attained by retaining 80 percent of a given mangrove area and converting not more than 20 percent to other uses.” This means there needs to be an 80:20 or 4:1 ratio of mangroves to ponds or other uses for maximized economic gain and, ultimately, environmental preservation.
Dr. Primavera has cited Manila Bay as an example of such proportion, sharing, “Following the science of a 4:1 mangrove to pond ratio for environmental sustainability, 44,000 hectares (80 percent) of these ponds in Manila Bay should be reverted to mangroves. This would restore the mangrove services of coastal protection, regulation of flooding, erosion control, and fisheries production.”
With the right species of mangroves planted in the correct places, we take a step toward science-based mangrove planting and away from misguided efforts. To fight the environmental crisis, Dr. Primavera's wisdom encourages us to harness the power of knowledge to ensure that the Earth, our only home, remains not just habitable in the decades but also abundant in resources.