Fishermen and scientists recover threatened mangroves in Baja California Sur, México

Monday 1 April, 2024
8 mins read


by Astrid Arellano

The mangroves and wetlands of Isla del Carmen, in the municipality of Loreto, Baja California Sur, were impacted by salt extraction for decades. Since the beginning of the 20th century, this economic activity even motivated the founding of a town in its territory to house the workers who traveled daily on cargo ships. The boom ended in the 1980s. Of all this, only ruins remained: buildings, machinery, a church and a dock. The island, located in the Gulf of California, was never the same again. A strong environmental deterioration has marked it to this day.

“This activity undoubtedly generated deterioration on the island. In the process, certain lagoons had to be flooded and let the sun do its job by evaporating the water, to obtain the salt that way,” explains biologist Arturo Peña, director of the Loreto regional office of the Wildlife Organization (OVIS) AC, which has been working for almost three decades in the conservation of the area. As a result, at least 200 hectares of mangrove were removed.

Peña remembers that, in the seventies, before the Loreto Bay National Park —which protects five islands, including Carmen—, the furor of the salt mine was experienced specifically in the place known as Bahía Salinas, in the southwest part of the island, where the communities of black mangrove (Avicennia germinans) were precisely located. .

“When the salt extraction activity ended, the island was abandoned and the people who lived there returned to the mainland to form the community of Ensenada Blanca,” says the specialist. Today, it is the grandchildren or children of those who were working in salt extraction who live there, and it is they themselves who, since 2021, are restoring the ecosystems of Isla del Carmen.

“We are 12 people from the community, five women and seven men, and we are fishermen. I am in charge of organizing the outings and the team,” says Alejandro Castro, community leader in Ensenada Blanca. A year ago, the work of this brigade began with cleaning actions on the coastline, in collaboration with the National Commission of Protected Natural Areas (Conanp). It was through this institution that they received the invitation from OVIS to work with mangroves.

“We trained and learned about the work that mangroves do. Now we know what they are for. Trees produce oxygen, they are what clean the air and protect many species, but also the coastline from hurricanes,” she explains.

In coordination with OVIS and the North American Environmental Information and Communication Center (Ciceana) AC, they are currently working on the rehabilitation of the hydrological system of the wetland, with the cleaning of the natural channels that were affected by the salt mine. They also work on the construction of vegetation terraces, created from the sediment extracted from cleaning the canals, to plant mangrove seeds on them. To date, they have accumulated 11 thousand mangrove propagules growing under the sun.

Restore in community

Seen from the mainland, Isla del Carmen impresses with its size. Its 27 kilometers long and another nine kilometers wide are home to desert vegetation where various species of bushes and halophytic plants abound. OVIS describe that the 15,100 hectares of its territory are made up mainly of large mountain ranges of volcanic rock and alluvium, with hills, plateaus and elevations that reach 479 meters above sea level.

According to the organization’s monitoring, the fauna of the island is very diverse, as there are records of 47 species of mammals, 19 of reptiles and one of amphibians. However, the best represented group is that of birds, with 86 species. The island is an important habitat for the brown pelican (Pelecanus occidentalis), the earwig (Fregata magnificens) and the blue-footed booby (Sula nebouxii). It is also a nesting site for resident seabirds such as the yellow-legged gull (Larus livens), the fishing hawk (Pandion haliaetus) and the American oystercatcher (Haematopus palliatus).

This is because the geographical location of the wetlands and mangroves in the northwest region of México makes them sites of great importance for the development of both resident and migratory waterfowl that use the Pacific migratory route.

“Mangroves, wherever they are, are important. They are associated with coastal bodies of water that are also part of the life cycle of many species of commercial importance in fishing, starting with shrimp,” describes Peña. But also, the mangroves of Isla del Carmen, which are among the northernmost in México, are a refuge for the food of large mammals such as blue and gray whales.

The restoration site covers an area of ​​50 hectares where there are patches of mainly black mangrove (Avicennia germinans). The project in Bahía Salinas intervenes in the flood lagoons that were used for salt extraction and in which the normal or daily flow of the tides was interrupted, modifying the environment.

As Peña describes, “what was done was to determine what the natural water flows that flooded those lagoons were like when they were completely open and active,” that is, before they were intervened by salt mining activity.

The first thing was to allow the passage of seawater to these lagoons again. The community team and specialists—with work done with pick and shovel—reopened and cleared the main and secondary natural channels to allow water to enter. This activity was accompanied by a Tidal Water Pumping System, consisting of the installation of a tube to connect the sea with the lagoon.

“The salinity is very strong there because that water is stagnant; That is the reason why the mangroves have not grown,” explains Alejandro Castro, the community leader of Ensenada Blanca. “Therefore, the first step is to make the channels to control the salinity of the sea, to ensure that the water enters and leaves, so that it does not remain stagnant,” he says.

“Although the different mangrove species tolerate high salinities, in a flood lagoon for salinity activity, we are talking about 80 to 85 parts per million of salt concentration, which is critical for the species,” explains biologist Peña. “That is why the idea is to introduce water so that the concentration of salinity decreases and allows the establishment of mangrove seedlings.”

The second stage consists of making terraces around each canal and planting mangrove seeds on them.

The vegetation terraces are built using the mud or sediment that is removed from the cleaning of channels – adds Alejandro Castro -, material with which they form rectangles between four and five meters long, by two meters wide, with a height sufficient to that the sea water does not cover them. Between each terrace, a meter of separation is left so that the water flows freely through the channels.

They currently have 40 terraces of this type and about two kilometers of open canals to feed the new Avicennia germinans plants, whose seeds were collected in the previous season by the community team, who has also been in charge of dispersing them using the broadcast technique. , that is, scattering the seeds by hand and randomly on each island.

“We also have red mangrove (Rhizophora mangle)—which is in Balandra Bay, on the other side of the island, where we collect its seed—but it is planted differently,” says Castro. “The seed is like a bullet. Then they are cut and buried standing, at a more or less prudent distance, one meter or one and a half meters,” he explains.

So far, the project has been successful. Of the 18,000 propagules or germinations of black mangrove and 2,000 of red mangrove collected, the survival and growth of 11,000 total seedlings was achieved.

In addition to these works, the current salinity of the water in the wetland is monitored in order to obtain technical information that is useful to analyze changes in the quality of the water in the system. For this reason, the team of specialists carries out monthly field trips to measure physicochemical parameters of the water such as salinity, temperature and total dissolved solids, at 11 different sampling points.

The results obtained so far are favorable: according to OVIS studies, in November 2023, salinity values ​​had decreased considerably. The following studies began in February 2024 and we will have to wait to obtain the new results.

Educate to conserve

The mangrove restoration project was not complete until the community as a whole became involved. In Ensenada Blanca, high school and university students, fishermen, tourism service providers and community authorities have been taught the importance of conserving these ecosystems.

That’s where the North American Environmental Information and Communication Center intervened (Ciceana) AC, an organization specialized in environmental education that allied with OVIS to function as the social arm of the project and for which they obtained financing from the SíMiPlaneta AC Foundation

“If the community is going to be living there forever, why not work and promote a culture of conservation in it? This goes beyond saying that the mangrove should not be littered or eliminated, but rather, reflect on why it is deteriorated like this. “That the community understands its context and how much has been lost,” explains Arisbeth Rosales, a biologist specializing in biological conservation and community development, operational director of Ciceana.

Thus, several workshops and community conversations have been promoted — where not only audiovisual and educational products are shared, but dialogue and reflection are promoted — which have impacted many more people about the importance of mangrove conservation and the health of the oceans.

“The dissemination of this message goes beyond the people to whom you spoke in the first instance or reflected with them. For example, in professional level students who will be future teachers, when they finish their training and start working with students, they will be replicators of the message of doing things better for the well-being of our environment and our ecosystem,” adds the biologist.

The same occurs with tourism service providers who now transmit information to visitors or the artisanal fishermen themselves who, even when their fishing practices are not so invasive, seek to improve them.

But the most moving work—says the biologist—is with childhood. There were many children who did not know the history of their own community. Now they know that a salt mine existed, that the activity caused the erosion of the island and the loss of the mangroves.

“Now they feel proud of their community, but they are also aware that not everyone lives in a landscape like the one they live in and that it is about to disappear if we do nothing,” adds Rosales.

What is coming for 2024 is to involve schools to be part of a volunteer program. “Let them go plant the mangroves or help in the activities. In other words, let them sweat within the project so that their awareness is a little more vivid. Let them know that it is difficult to restore and that is why it is better to conserve it,” says the biologist.

In the future that Alejandro Castro imagines for Isla del Carmen, the landscape is seen to be green, with large mangroves where species can live and reproduce without threats. To achieve this definitively, we must sow the seed of sensitivity and responsibility in the new generations.

“Even we are going to give talks to schools, so that the younger ones bring that into their minds, something that we never had as children. Before it was about taking him out and taking him out to sea. It is not just going and filling our boat with products to have money. Now it has to be different,” says the fisherman. “One of the dreams I have always had is to give something back to the sea. I have been in it for 30 years now, because I started fishing when I was 11 years old. I want to instill in the youth that good things can be done, that a little of everything it has given us can be returned to the sea.”

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Source: from Noroeste Nacional on 2024-03-29 18:20:42

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