Restored mangroves in Santa Catarina mitigate extreme weather phenomena

Amid the worsening of extreme weather phenomena in Rio Grande do Sul, a project in the neighboring state of Santa Catarina, which also suffers from hurricanes, completes its first year of existence showing that solutions based on nature itself, such as the replanting of native mangrove species , help reduce floods and other catastrophes caused or worsened by human action.

Over the past 12 months, members of the Raízes da Cooperação Project and almost 2000 volunteers, most of them students from public schools located near the mangrove, have already cut down and managed invasive species called pine in an area of ​​almost eight hectares, or about the size of a medium-sized football field in the Brazilian championship. This was the first stage of the Project.

“Minimizing and mitigating extreme weather phenomena involves nature-based solutions. As for flooding, one of these solutions is the protection of recharge areas and ecosystems that protect the environment, and mangroves are between the ocean and the continent, that is, in regions subject to flooding from the ocean and rivers”, explains Dilton de Castro, ecologist and coordinator of Raízes da Cooperação. “Mangroves absorb carbon dioxide – and research indicates that they absorb five to 15 times more carbon dioxide in the soil, subsoil and plants than the Amazon and Atlantic forests – and contain erosion caused by the advance of the sea. The conservation of remnants and the restoration of areas that were transformed into landfills and shrimp farming are important for society, especially for vulnerable populations who live on the margins of these environments”, adds Castro.

The census carried out by IBGE and released in 2022 showed how important research and action on mangroves is for a country like Brazil. According to the survey, 111.28 million people, 54.8% of the Brazilian population (of 203.08 million), live in a strip of national territory located at a distance of up to 150 kilometers from the coast and, therefore, in impacted regions for everything that happens in mangroves and other coastal ecosystems. In relation to 2010, there was an increase of almost five million people living in this territorial strip, although there was a 1% decrease in the number of people living on the coast.

The first phase of Raízes da Cooperação, which was designed and operated by the organization Ação Nascente Maquiné (Anama) and financed by Petrobras, is developed on two coastal islands in the Santa Catarina municipality of Palhoça. According to Anama, the total area that has already been invaded by exotic species corresponds to more than seven football fields.

The objective of the Project in 2024 is to make 30 trips to the mangroves, with education professionals and 900 students from public schools, who will work in 54 hectares of mangroves, restingas, wetlands and forests in the territory. They will plant another three thousand seedlings of native species on 10 hectares of the islands and around the Visitor Center of the Serra do Tabuleiro State Park – a conservation unit located in the Santa Catarina municipalities of Florianópolis, Palhoça, Santo Amaro da Imperatriz, Águas Mornas , São Bonifácio, São Martinho, Imaruí and Paulo Lopes.

“The lack of knowledge of the importance of this ecosystem on the part of society ends up being a risk. What we don’t know we think is useless. That is why education, social mobilization and the promotion of citizen science are important conservation instruments”, says the project coordinator.

According to him, the mangroves located in Santa Catarina remove carbon from the atmosphere and place it in underground structures, that is, they store in the soil this chemical element present in Greenhouse Gases, which cause warming and changes in the planet’s climate. Other types of mangroves, such as those located in Amapá, Maranhão and Pará, also capture carbon, but store it in their aerial parts, that is, the leaves and trunks, which can reach up to 30 meters in height.

The main threats to mangroves, according to Castro, come from urbanization, the irregular introduction of invasive exotic species, fires, rising sea levels and the irregular dumping of sewage. To a large extent, recalls the ecologist, these negative impacts arise from social ignorance about the environmental importance of these ecosystems.

“Mangroves are in the tropical zone of the entire planet, with the largest patches there in Indonesia. Here in Brazil, they are found in the coastal strip between the Amazon and Santa Catarina. Recife, Salvador, Rio de Janeiro grew by filling in mangroves, restingas and other ecosystems considered “stinky” places that attracted mosquitoes”. The lack of basic sanitation and the deposit of solid waste (garbage), explains Dilton de Castro, who also lists other dangerous enemies of mangroves.

In the Northeast, he explains, mangroves are being widely and quickly converted by economic groups into shrimp farming farms. “In Santa Catarina, the main problem is the landfill for road construction, in addition to the invasion by exotic species, especially pine. In the Santos region, in São Paulo, a species of exotic mangrove originating in the East was recently detected and found within the native mangrove, which is already beginning to spread in Baixada Santista”.

Castro recalls that the occurrence of mangroves on the Brazilian coast ends on the coast of Santa Catarina. “They are found approximately between the Tropics of Cancer and Capricorn. From Laguna, in the extreme south of the State, the contact between the fresh and salt waters of the rivers with the sea is replaced by other ecosystems that fulfill a similar function. Among them, the so-called salt marshes, which also absorb, capture and fix carbon from the atmosphere”.