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Ecology

Mangroves: Nurseries of the Sea

Mangroves provide innumerable services to the sea, acting as a nursery where many of the animals that contribute to ocean biodiversity and provide sustenance for humans are born and thrive.

By: Javier A. Pinzón
Photos: Steven Paton, Milton García, Javier A. Pinzón

Mangroves are tropical forests on the seashore that make up the border between dry and wet, salty and fresh. Their roots intertwine, forming a chaotic and the same time, beautiful landscape of trunks, branches, and roots. In this framework of impenetrable barriers, fish and shrimp take shelter and mollusks, sponges, and others attach themselves and live. Beyond their immeasurable beauty, mangroves are of vital importance to the stability of the two environments they separate: the land and the sea.

According to Steven Paton, director of the Physical Monitoring Program of the Smithsonian Tropical Research Institute (STRI), the services that mangroves provide to the ocean are immeasurable. They are the nursery where most of the animals that contribute to ocean biodiversity and constitute the diet of human beings are born and thrive. Although mangroves occupy just 3% of the Earth’s surface, part of the life cycles of approximately 70% of the organisms captured in the ocean have taken place there.

Dr. Eugene Turner, a professor at Louisiana State University, estimates that, for each species of mangrove that is destroyed, nearly 1,700 pounds of commercially important marine species are lost annually. The services that this ecosystem provides to our world can’t be overestimated. In coastal regions, mangroves are a pioneering plant. They arrive first and form a home so that later, many other species of plants, and especially animals, can establish themselves.

Mangroves also serve as a barrier, protecting us from waves and storms. Areas located behind mangroves are better protected against storm surges, winds, tropical storms, hurricanes, and tsunamis. In the areas where mangroves have been cut down, coastal erosion takes place.

Mangroves also help to slow down climate change. They make up just 1% of the total area of the world’s tropical forests but absorb up to five times more carbon dioxide per 2.5 acres, which they store in their leaves, trunks, roots, and in the soil.

As if that weren’t enough, Paton explains that they are also very important for migratory birds. With the changing of the seasons, each year millions of birds traveling from North America to South America require “stopovers” to rest and feed. In the mangroves of Panama, for example, the Panama Audubon Society has reported the presence of nearly two million shorebirds regaining their strength before continuing on their journey. If they do not find this ecosystem along their path, the diversity of migratory birds will be reduced.

There are 54 known mangrove species in the world, distributed among twenty genera and belonging to 16 families. They are usually associated with coral reefs, sea grasses, and mudflats.

The Risks

Despite the many important services that mangroves provide, human beings, both directly and indirectly, are contributing to their demise. According to the United Nation’s Food and Agricultural Organization (FAO), the local and global changes caused primarily by our anthropogenic footprint have resulted in the loss of nearly 10 million acres of mangroves over the last three decades.According to Paton, mangroves occupy areas on the coasts that are also used for other purposes. For this reason, they have been cleared to install shrimp farms or tourist areas, and even for the expansion of cities, as is the case of the Juan Díaz area in Panama City. Chemical pollution, sedimentation, and garbage are other contributors to the destruction of mangroves around the world.

Scientists are also discovering that climate change is a new factor contributing to the destruction of mangrove areas. Paton explains that the rise in sea level as a result of warming causes erosion, and the first ecosystem to confront this increase is the mangrove: the border between sea and land. Today we can see that strong waves erode coastal areas, affecting mangroves. This can be expected to worsen in the future with a further rise in sea level.

In fact, the most conservative calculations predict that the sea level will rise by 1.6 feet by the end of the century, which will most certainly cause erosion along the coasts, destroying almost all the mangroves of the Panamanian Atlantic. If we accept the most extreme predictions, which suppose an increase of 13 feet, this would mean the destruction of almost all the mangroves. Because the mangrove is much higher on the Pacific side, it could possibly survive, but it would have to recede. However, this process would be hampered because the land is being used for other purposes, such as livestock.

Another event that generated a great die off, Paton reports, was the El Niño phenomenon of 2015-2016, one of the strongest on record. In Australia, this event caused many mangroves to die. It is thought that something similar happened in the Bay of Panama in 2015, when thousands of trees were stressed and died a year later. The hypothesis is that high salinity due to the lack of rain stressed the mangrove trees, leading to their death.

Mitigation Measures

Luckily, it’s not all bad news. Many countries have signed on to the Ramsar Convention, a treaty in which signatories pledge to work for the wise use of the wetlands within their territories, in addition to establishing a list of Wetlands of International Importance (the “Ramsar List”), guaranteeing their effective management, and undertaking international cooperation for transboundary wetlands, shared wetland systems, and shared species.

According to Paton, the mangroves are very good at colonizing areas suitable for their habitat. Panama has some good examples of this: Panamá Viejo, Costa del Este, and Juan Díaz. As soon as mud appears with water, the mangroves begin to colonize, which tells us that if given the opportunity, the mangroves can regenerate.

 


Exhibition on Mangroves

In an effort to raise awareness about the importance of mangroves and the urgency of their protection, STRI, the National Secretariat of Science and Technology of Panama (SENACYT), Ramsar Regional Center, Centro de Incidencia Ambiental-CIAM, City of Knowledge Foundation, Audubon Society of Panama, and CeCop Program are holding an exhibition in Panamá Viejo.

The exhibition will be open at the Visitors Center of the Patronato in Panamá Vieja, Tuesdays through Sundays from 8:30 a.m. to 4:30 p.m., until September 16th.

Using a combination of photos, drawings, and educational text, the exhibition explains what mangroves are and the ways they are important to the environment and human beings. The exhibition also highlights the threats mangroves face and the work of scientists and conservationists to study, understand, and conserve mangroves in Panama.