Despite their huge ecological and economic value, mangrove forests are disappearing much faster than the average rate of forests around the world. Fortunately, although still patchy, awareness of their ecological and economic value is rising and there are glimmers of hope in the shape of pioneering conservation and community projects.
Mangroves are groups of trees and shrubs that grow in the intertidal zone of sheltered coastlines and estuaries. They are one of the many living systems that shape the boundary between land and sea.
The Sundarbans is the largest contiguous mangrove forest in the world.
Image: Sarangib pixabay-1225627
The term “mangrove” is used to describe both the individual plants and the broader ecosystem of the mangrove forest.
Dozens of species of shrubs and trees
There are dozens of different species of mangrove trees and shrubs. These have adapted to thrive in saline, low-oxygen conditions, in soils formed by the fine sediments that accumulate due to the slow movement of water.
Mangrove forests cannot withstand freezing temperatures. They only grow in tropical and subtropical regions near the equator, contained roughly between 25° North and 25° South.
Within this confined band around the earth, mangrove forests are widely distributed across 123 nations and cover a total of 152,000 square kilometres.
On a global scale, however, they are quite rare, accounting for less than 1 percent of all tropical forests.
Mangroves sustain millions of people
Over 100 million people live within 10 kilometers of large mangrove forests. The forests benefit these populations in many ways, from providing food security, fishery and forest products, to giving clean water, and protection against extreme weather.
A distinguishing feature of mangrove trees is that they appear to be standing on stilts, propped up by a dense tangle of roots that allows them to survive the daily rise and fall of tidal water.
Mangrove forests help to stabilize the coastline and protect it from erosion. Their intricate root systems also provide shelter for many species of fish and other creatures, below and above water.
The largest contiguous mangrove forest in the world is the Sundarbans in the Indian subcontinent, on the delta where the Ganges, Brahmaputra, and Meghna rivers flow into the Bay of Bengal.
The Sundarbans is renowned for its biodiversity, which includes threatened species such as the Bengal tiger, the estuarine crocodile, and the Indian python. It was designated a UNESCO World Heritage Site in 1997.
Mangroves under threat
Over a quarter of the earth’s original mangrove cover has now been lost – driven largely by land conversion for agriculture and aquaculture, helped along by coastal development and pollution.
For example, in the Philippines, more than 50 percent of mangrove forests have been wiped out since 1918, largely to make way for aquaculture ponds.
It is estimated that mangrove forests are disappearing some 3-5 times faster than the average rate of forest loss.
The economic impact of the loss of mangrove forests is estimated to be in the billions of dollars. Mangroves also have a superior ability to store carbon, at a global rate of 22.8 million tons per year.
More recognition for mangroves
Fortunately, awareness that we cannot afford to lose these vital forests is growing.
For instance, following a proclamation in November 2015 at the UNESCO General Conference, the 26th July 2016 was the first International Day for the Conservation of the Mangrove Ecosystem.
Glimmers of hope are also growing as more initiatives and projects start to bear fruit.
Sri Lanka first nation to protect mangroves
In 2015, Sri Lanka became the first country in the world to promise full protection for mangrove forests.
In that year, the Sri Lankan government launched a scheme that includes replanting projects, creating mangrove nurseries, and offering job training and microloans to help people make a living in a way that supports the mangroves.
Although it is early days, 2 years on, the scheme appears to be working. Seacology, a California-based conservation group that is backing the Sri Lankan project say the progress so far “has exceeded our expectations.”
“Tens of thousands of acres of existing mangrove forests are now legally protected, hundreds of thousands of mangrove seedlings have been grown and planted, and thousands of women have obtained job training and financing,” they add.
Replanting after the 2004 tsunami
On 26 December 2004, the worst tsunami on record killed more than 227,000 people in South-East Asia. The majority of deaths (167,000 people) occurred in the Indonesian province of Aceh, which was hit by a 20-metre wave.
Unfortunately, many of the mangrove forests that could have afforded some protection from the wave had been uprooted to make way for aquaculture ponds, such as for farming shrimps.
Since then, however, thousands of hectares of mangrove forests have been replanted as a tsunami shield.
Blue forests project
Another leading initiative is the Global Environment Facility (GEF) and United Nations Environment’s Blue Forests Project.
The project aims to improve the management of mangroves by focusing on the value of the goods and services they provide to support livelihoods and wellbeing around the world.
One example is in Gazi Bay, Kenya. Here, the Mikoko Pamoja (literally “Mangroves Together”) project is the world’s first initiative to link conservation of mangroves to the global carbon market.
The project seeks to raise income from forest resources, gain carbon credits, and promote other activities that benefit the community, such as beekeeping and ecotourism.
It also involves helping communities to police illegal mangrove harvesting, and spread local knowledge about how to replant mangroves.
The Mikoko Pamoja model is to be repeated in nearby Vanga Bay (see the video below) and also across other Blue Forest sites around the world, from Abu Dhabi to Ecuador, Indonesia, Madagascar, and Mozambique.
Mangroves are part of a bigger picture
Meanwhile, in Florida, coastal ecologists are concerned that mangroves could become too successful and expand at the expense of salt marshes.
Although less effective than mangroves at stopping waves and slowing erosion, salt marshes have other benefits that are perhaps harder to quantify. For example, they make better carbon sinks.
A reduction in salt marshes in favour of mangroves could also be harmful to many species of birds that rely on the salt marshes for food, places to nest, and clear sightlines for spotting predators. Mangrove forests do not provide these things.
Video – the Mikoko Pamoja “Mangroves Together” project
The following video from 101 Visions summarizes the pioneering work that is bringing together mangrove conservation with village development in Gazi Bay, on Kenya’s south coast.