Editor’s note: even though originally written to celebrate the importance of mangroves in tropical ecosystems, today we are highlighting this blog in advance of the International Day of the Conservation of the Mangrove Ecosystem, adopted by the General Conference of UNESCO in 2015 and celebrated each year on 26 July, to raise awareness of the importance of mangrove ecosystems as “a unique, special and vulnerable ecosystem” and to promote solutions for their sustainable management, conservation and uses.
Mention the word “tropical” and my mind will conjure up uncomplicated images of deserted islands, toucans in rainforests, and orange-colored pineapple-infused smoothie flavors. In my daily life in Washington, D.C., I think of the Tropics on the most basic and self-centered terms: they are distant, warm, and probably quite wet.
As such, I found the International Day of the Tropics to be a timely opportunity to learn more about the topic. The United Nations observance this Saturday, June 29, celebrates “the extraordinary diversity of the tropics while highlighting unique challenges and opportunities nations of the Tropics face.”
It’s time for me to move away from my conception of “tropical” as an adjective and towards an understanding of the Tropics as an actual region of the world. Approximately bound by the tropic of Cancer and the tropic of Capricorn, the Tropics are a vast and significant portion of the globe. They’re huge — they cover 40 percent of the world’s total surface area, and provide for about 80 percent of the Earth’s biodiversity, plus much of its linguistic and cultural diversity.
There is greater biodiversity in the Tropics, so there are higher proportions of threatened species. Meanwhile, alongside higher levels of poverty, there are higher proportions of undernourishment and higher proportions of urban populations dwelling in slum conditions. From urbanization and demographic change to climate change and deforestation, the issues that impact the Tropics are widespread, complex, and interconnected.
More than anything, the International Day of the Tropics brings attention to the sheer scope of the tropical zone and the far-reaching implications of its issues. Taking in the five continents and numerous countries covered by the span of the region on the map, I began to look for more specific ways I could understand the Tropics — how could I better comprehend the tightly knit relationships that constitute such a large and important area?
This question led me to the mangrove forest. Of all tropical forests worldwide, less than 1 percent is mangrove; however, 95% of the world’s mangrove forests by area and 99% of mangrove species are found in the Tropics. The mangrove ecosystem is unique. It’s home to a diverse array of flora and fauna, and a key habitat for fisheries. This means that mangroves ensure local food security — at the same that they protect coastlines from erosion, improve water quality by filtering out nutrients and sediments, and absorb massive amounts of carbon.
The mangrove ecosystem is valuable for both the people and the environment of the Tropics. Yet, human activities are also a central threat — coastal development and aquaculture destroy mangrove habitats. Over a quarter of the world’s original mangrove cover is already gone.
The loss of mangroves is, in turn, a loss for humans. Fisheries resources are destroyed. Dams, pollution, or irrigation upstream alter local water conditions. Coastal communities, such as those living along the Bay of Bengal, face rising sea levels and increasingly dangerous weather.
What, then, can be done? In Bangladesh, over 200 hectares along the coastline were forested with mangroves, under the country’s National Adaptation Programme of Action, Climate Change Strategy and Action Plan, and Seventh Five-Year Plan (2016–2020).
With support from the GEF-Least Developed Countries Fund, the UN Development Programme (UNDP) and Bangladesh’s Forest Department and Forest Research Institute planted 176,000 mangrove seedlings from 10 different species and raised them in 10 forest ranges. The greenbelt of mangroves protects the people living near Bay of Bengal from natural disaster — as well as protecting the land from erosion, increasing biodiversity, absorbing carbon, and providing a nursing and feeding ground for fish.
As I read more about mangroves, I began to realize that the future of all people is closely intertwined with the future of the environment. That’s why it’s so essential to understand our relationship to the environment, as well as the ways that the environment provides for all of us.
So what did I learn from my brief investigation into the International Day of the Tropics? Mostly that I have a lot more to learn — that the tropical zone, as part of the global environmental system, itself consists of numerous intricate, diverse, and tightly-knit systems, both human and environmental.
And also — that I’ll be more prepared for UNESCO’s International Day for the Conservation of the Mangrove Ecosystem next month, on July 26.
Some amazing facts about mangroves:
Mangroves may combat coral bleaching and ocean acidification.
Reefs and coastal forests aren’t as distinct as you may think — the roots of mangroves provide a place for young corals to grow, and mangrove forests are a refuge for corals at risk of extinction from coral bleaching.
Mangroves act as nurseries for thousands of fish species.
Beyond corals, juvenile fish — from 1-inch gobies to 10-foot-sharks — grow in the nurturing underwater habitat that the roots of mangroves provide.
Mangrove forest can absorb as much as 10 times the carbon of a similar area of terrestrial forest.
Mangroves are capable of storing vast amounts of carbon, making them essential to minimizing the impact of climate change.
It’s important to protect mangroves, because they are difficult to replant.
Mangroves roots give the coastline its shape, holding back tidal water and filtering out nutrient-rich sediments. This means that, once mangroves are lost, tides and currents erode the land and shift its sediments, making it difficult or impossible for mangroves to grow back.
No other species of tree in the world can survive in saltwater.
Mangroves are unique in their ability to dwell in high saline water and soil. They tolerate levels of salt that would be toxic to other plants by excreting this salt through their leaves.
