Amazon mangroves are threatened by climate change – 04/07/2024 – Environment

Muddy soil. Sulfur smell. Trees with high roots, capable of expelling excess salt from the soil. At first, it is difficult to believe that there is an exuberance of life in the mangroves, but they are much richer in biodiversity than one might imagine.

In an area that stretches for almost 8,000 km on the north coast of Brazil, from Amapá to Maranhão, there are mangrove forests with trees up to 40 meters high. In this region, mangroves become a rich and biodiverse ecosystem.

Mangroves are areas where freshwater from rivers meet the sea and make up typically tropical coastal ecosystems, not existing above a certain latitude where there is a strong variation in temperature.

Several species of animals also live there, both invertebrates and vertebrates, such as birds, fish and crustaceans, such as the uçá crab.

The Amazon mangroves are the most extensive and best preserved in the world, according to a study published last year in the scientific journal Anais da Academia Brasileira de Ciências. This is due to several factors, according to the authors, but mainly due to the forest cover that covers the surrounding estuarine areas.

In the study, the authors estimate that less than 1% of its entire length, which is around 7,800 km^twohas suffered devastation in recent years.

“It’s wonderful to see the mangroves here, because they are really beautiful”, explains José Francisco Berrêdo, geochemist and professor at the Museu Paraense Emílio Goeldi, in Belém, who has been studying the region’s mangroves for 40 years.

He cites the low population density in the region and the presence of conservation units along the coast as the main factors that explain the conservation of the ecosystem.

The high biodiversity can be explained by the presence of large rivers, which flow into the mouth of the Amazon, allowing for a greater mix of fresh and salt water, and the low population density.

According to Berrêdo, studies with paleomangroves (fossil records of mangroves) indicate that they were not always there. “The mangrove responds to climate variation, so a major change is a danger to the existence of the mangroves. [climática]”, it says.

Marcus Fernandes, biologist and coordinator of Lama (Mangrove Ecology Laboratory) at UFPA (Federal University of Pará), says that there are characteristics that differentiate Amazonian mangroves from others spread along the coast of Brazil.

“In the case of the Amazon, we have a wealth of ecosystems, which also differs from the mangroves of the Northeast and Southeast,” he explains. “But each one responds to some particularity, that’s why we are mapping the species [de mangue] in the Amazon and thinking about strategies for genetic variability of populations and replanting in areas that have suffered deforestation”, says Fernandes.

In the race against time to protect mangroves amid the climate crisis, public policies such as the creation of environmental preservation areas by the federal government help keep this forest standing. However, in recent years, the growing role of predatory fishing and human exploitation in the region has put pressure on the Amazon mangroves.

One of the policies that enabled the preservation of mangroves was the creation, from the 2000s onwards, of conservation units known as Resex (extractive reserves) covering the entire coast of Pará to Maranhão.

There are currently 14 Resex in the region, where, according to ICMBio (Chico Mendes Institute of Biodiversity), 22 thousand families live in an area of ​​approximately 369 thousand hectares between mangroves and water depths.

Ednaldo Gomes da Silva, environmental manager and head of the protection thematic area at ICMBio’s Integrated Management Center of Bragança (PA), highlights the importance of creating conservation units in the region as a way of guaranteeing the preservation of the ecosystem.

“With the decree of these four municipalities, we will close the ecological corridor [nome dado a um contínuo de florestas] which will further increase this importance [dos manguezais].”

According to him, in addition to greater control over the quantities of natural resources extracted from the forest, Resex helps maintain extractive activity at a sustainable level in the region.

“The relationship [das comunidades nas Resex] with mangroves it is indisputable, because they depend on that resource and naturally preserve it. It is difficult for there to be cases of exploitation of riverside residents, of community members, who go there every day to get their food. If it runs out for him, he will be left without his livelihood”, he says.

The view that the populations living in the Resex live in harmony with the mangroves has been well demonstrated since before the creation of the conservation units, explains the anthropologist and professor of the postgraduate program in Sociology and Anthropology and researcher at the Aquatic Ecology Center and Fisheries at UFPA Voyner Ravena.

“The Resex, they arrive as a legal set of reorganization of the territory that, in general, also ends up removing a little of that history, of the past resource of that location, but it must never forget that there were leaders there who previously, through their relationships with nature, they designed, chose, dictated the way in which the territory was used by the traditional population”, he explains.

In this sense, predatory fishing is the main threat to mangroves. “Shrimp trawling [que tem forte impacto marinho] previously came with more than 100, 120 species of accompanying fauna [como são chamados os animais que vêm junto na captura]. Today, 15 years later, for a ton of pink shrimp caught, there are around 60 species, that is, in less than two decades, you have halved the diversity”, he states.

Silva states that the reduction in fishing stocks in the region over the last ten years is indisputable. “Before, in an hour of fishing, you would bring your lunch, your dinner. Now, to do that, you have to spend much more time [na pesca] and sometimes it doesn’t bring anything”, he explains.

For Queren Lobo, master in sociology and currently a doctorate in anthropology at UFPA, the relationship between fishing populations and mangroves goes beyond food.

“It is also expressed in song lyrics, in carimbó compositions, in the aesthetics and art of these communities. So much so that the very definition that is today in the Snuc legislation [Sistema Nacional de Unidades de Conservação] reaches this dimension.”

The Resex are the only conservation units that also aim to preserve man’s relationships with the environment, says Lobo.

“They see themselves as part of nature and from this comes this thought of care, of zeal, that it is necessary to take care so that I can fish in the future. It is necessary to use the resource appropriately, so as not to miss it.”

If the Brazilian government’s interest in exploring oil in Foz do Amazonas materializes, experts fear that the drilling of wells — which are located approximately 150 km off the coast of Amapá — could generate impacts in the region and affect organisms that use the mangroves as a nursery. .

Berrêdo also highlights the fragility of natural ecosystems due to climate change. “If the pressure on the mangroves continues, they may eventually disappear,” he concludes.

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CATEGORIES OF BRAZILIAN CONSERVATION UNITS

Understand the classification according to Snuc (National System of Conservation Units)

– Full Protection Units: in order to preserve nature, only the indirect use of natural resources is permitted, which is why the rules and regulations are restrictive. The following categories belong to this group:

– Sustainable Use Units: combines nature conservation with the sustainable use of part of natural resources. This group is made up of the categories:

• APA (Environmental Protection Area)

• Area of ​​Relevant Ecological Interest

• Flona (National Forest)

• Resex (Extractive Reserve)

• RF (Fauna Reserve)

• RDS (Sustainable Development Reserve)

• RPPN (Private Natural Heritage Reserve)

_{The series of reports Mangues Amazônicos is supported by the Pulitzer Center’s Rainforest Journalism Fund}