New agricultural practices are trying to stop the decline of this amphibious forest, victim of overexploitation and climate change. By Théa Ollivier (Dassilame Sérère, Sénégal) for Le Monde Afrique
With her ankles stuck in the mud at low tide, Marianne Ndong scans the half-hectare of mangrove she helped replant three years ago on the outskirts of her village, Dassilamé Sérère, in the Sine Saloum delta in southern Senegal. "Without the mangroves that hold back the water, our homes would disappear, and us with them," explains the 39-year-old oyster farmer, wearing a blue and yellow wax cloth.
In West Africa, 25% of the area of this amphibious forest disappeared between 1980 and 2006, according to a team of American researchers. The cause of this decline is the overexploitation (for firewood or construction) of mangroves, these trees with aerial roots that live in brackish water. Climate change is also to blame, with rising temperatures, drought and water deficit accelerating water evaporation and thus increasing the concentration of salt that kills mangroves.
With the erosion of the coastline and the silting up of the channels (called "bolongs") that result, the fragile ecosystem is gradually deteriorating. According to the United Nations, mangroves are disappearing five times faster than forests.
In the commune of Toubakouta, five hectares have been replanted by communities over the past three years, with a survival rate of 87%. "All around the young mangroves, we notice an improvement of the soil: crabs and mollusks circulate, the texture of the soil is richer. Next year, we will be able to plant in areas that had become deserted and sandy, and which have become suitable for reforestation," explains Mamadou Bakhoum, coordinator of the inter-village development association (AIVD). This allows us to continue the process of reclaiming land slowly but surely."
But the damage is already there: "When I was a child, we had trees and fruits that we no longer find today," notes Marianne Ndong, who blames the salinization of agricultural land that has become uncultivable. The mangrove is a protective zone between the land and the sea, which has an impact on the quality of the soil and therefore on its productivity. It also allows the capture and storage of carbon. In total, at the global level, 21 billion tons of CO2 are stored in this vegetation, according to a July 2021 report by the NGO Wetlands International. "This space is vital for the species that feed and reproduce there, but it is also important for us, because it protects us and feeds us," pleads Marianne Ndong, who earns her income from the mangrove.
The women of three villages have joined together to adapt to the increasing scarcity of wild oysters. At the bend of a bolong, about thirty of them work with their ankles buried in the mud at low tide. In this small lagoon in the middle of the mangrove, they raise local oysters, whose spat are fixed on garlands of immersed shells where they develop in clusters. They then grow them in floating bags. Once raised for a year on the oyster farm, the oysters are transferred to the newly built disgorging tank where they release the impurities they have consumed. Then they are sold grilled, mainly to French and Belgian tourists.
A new production line was set up three years ago, which remains artisanal but is more modern and sustainable, according to its creators. "Traditionally, my parents and grandparents used to cut the roots of mangrove trees to harvest wild oysters, but this contributed to the disappearance of the mangrove," recalls Marianne Ndong.
In addition to not respecting the environment, the traditional method is not profitable," adds Mr. Bakhoum of AIVD. “So, we had to change behaviors to both generate money and solve an ecological problem." The agronomist by training points out that the poles on which the oyster garlands are hung form a barrier in front of the mangrove that the woodcutters can no longer cross. And instead of selling a kilogram of dried oysters for 3,000 CFA francs (4.5 euros), the women can now sell a dozen for 2,000 CFA francs. In the last three months, they have been able to sell 3.7 tons of oysters for a turnover of 15 million CFA francs. "My life has changed a lot, I can now pay for my children's education," says Marianne Ndong, who also works in organic market gardening and beekeeping.
Some sixty beehives have also been installed by the AIVD: an additional source of income, as the highly prized sweet-salty mangrove honey is sold at a higher price. It also makes it possible to bring back colonies of bees. Aggressive, they protect the forests where the woodcutters no longer dare to venture. "I had learned that we had to kill the bees to harvest the honey, now we have equipment to protect us," says Marianne Ndong. But with only five to ten kilograms of honey harvested per hive every three months, production is still insufficient, says Mamadou Bakhoum, who emphasizes the strong potential of this sector. "It is difficult to expand production because of the aggressiveness of bees, so we are working on selecting a species," he explains.
All these projects have been made possible in part by funding from the International Fund for Agricultural Development (IFAD), a United Nations agency that has invested $8.89 million (about 7.9 million euros) at the national level to "improve smallholder food security and resilience to environmental degradation and climate variability. The idea is to let the populations exploit these resources without damaging the mangrove, while at the same time benefiting from them.
But the problem remains to put all these initiatives on a national scale, to have a real environmental impact on the 200,000 hectares of mangrove in the country. "There is a lack of coordinated actions of protection, conservation, restoration and development of the mangrove. We would like to see a national plan from the government or local authorities to save the mangroves in these areas," says Semou Diouf, IFAD program officer in Senegal. We need to invest more in climate change adaptation activities; this is what will save the ecosystems that support small producers.
For Mamadou Bakhoum, the challenges are still numerous. "The list of what we lack is long," says the coordinator, for whom the projects are still too small to really protect the mangrove, since income-generating activities only affect a part of the population.
Théa Ollivier(Dassilame Sérère (Sénégal))
This article is translated from French from the article published on Le Monde Afrique.
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