Photo by xavi talleda via Flickr CC
Mangroves are a special ecosystem. Found all over the world, they thrive in the in-between zones of land and sea, and act as nurseries for a vast variety of animals, grocery stores for humans, a buffer between homes and massive storms rolling in off the sea, a regulator of sediment and nutrients sliding from shore to sea, and more. Yet while they can feed millions of people and are an important resource, we often consider them no-mans-land, useless or worse than useless, something to be ripped up and replaced with resorts or shrimp ponds. Thankfully, there are people who see the innumerable benefits of mangroves and are coming up with ingenious ways to restore them before it is too late. Kennedy Warne is the author of Let Them Eat Shrimp: The Tragic Disappearance of the Rainforests of the Sea. He traveled the world visiting mangroves in many countries, witnessing their use, destruction, and restoration.
Photo by NatalieMaynor via Flickr CC
Little Shrimp, Jumbo Problem
Warne launches into the problem of disappearing mangroves by highlighting one of the key culprits -- shrimp ponds. Warne illustrates how shrimp farming can be an economic boon to a country, but at the expense of local ecosystems and the people who rely on them.
Americans consume an average of four pounds of shrimp per person per year. It is a commodity that is taken from countries whose ecosystems are destroyed and food security weakened, and sent to wealthy countries that have little practical need for yet more protein.
Elaine Corets, Latin American coordinator of the mangrove Action Project points out that not only do the shrimp ponds ruin the land, but the sea is pillaged to keep them going as well. "Between two and three pounds of feed are needed to produce one pound of shrimp. Depending on the proportion of fish in the feed (typically around 30 percent), shrimp farming operations may be net consumers, rather than producers, of fish protein," Warne writes.
Between the shrimp ponds and the resorts built atop filled-in mangroves (and serving all-you-can-eat shrimp buffets), the mangroves are disappearing fast.
In places that move into shrimp farming, the impact on ecosystems is obvious, and devastating. NASA's Earth Observatory shows the changes in shocking detail -- the bottom image shows how much of Guayaquil, Ecuador was converted to shrimp ponds but salt flats still remained. The top photo shows how even those were converted to shrimp ponds. Ecuador is among the world's largest shrimp exporters.
Mangroves As Shark Nursuries
The mangroves serve a number of important purposes, and one of those roles is that of nursery for fish. Lemon sharks are a key species using mangroves in tropical areas such as Bimini as a place of protection until they're big enough to face the open ocean. However, as resorts plow over mangroves, filling them in and building atop a once-rich ecosystem, the lemon sharks -- and many other species -- are left without a place to grow up.
Warner writes, "If aquaculture has been the prime driver of mangrove decline in poorer countries, property development has been the villain in rich nations and their offshore playgrounds.
"...One man looks at Bimini's mangrove expanse and sees condos and a golf course. Another sees an ecotourism opportunity. Another sees a site for scientific research. Which vision should prevail?... The crux of the issue is undoubtedly valuation, but the difficulty is that some values are highly tangible while others are not."
Like so many other precious ecosystems, the long term value of biodiversity and thriving species is lost to the immediate return as resource after resource is stripped and sold away.
However, mangroves do have a value if we take the time to calculate it. For example, Warne writes, "A study of fish landing at thirteen sites in the Gulf of California recently found that yields were directly proportional to the length of coastline inhabited by mangroves. The researchers determined that the presence of mangroves was worth $37,500 per hectare ($15,000 per acre) per year for its fish-related services. This figure is 600 times the value the Mexican government places on mangrove land, which is acquired cheaply for tourism development and conversion to shrimp farms."
Photo by Roberto Verzo via Flickr CC
"They Think It Won't End"
A big part of the problem is how invisible mangroves are to most of the people who could protect them. Even for people who use the mangroves for their livelihood may not be aware of the impeding destruction their mangroves face -- not just from development but also sea level rise.
As Warne points out, mangrove destruction is not as well known as rainforest destruction, thus it is more difficult to get activists behind their conservation and reforestation. Mangrove destruction is going on at the same as rainforest destruction, "but while rainforest destruction quickly attracted urgent and vociferous opposition, the removal of mangroves was off the public radar. For most people, it still is."
And without awareness of how fragile the future of mangroves is, the less prepared we are to defend them from destruction. Like most things, we think mangroves simply won't disappear. But they are nearly gone.
Roy "Robbin" Lewis III, who has spent 35 years rebuilding mangrove habitat, is quoted in the book noting that mangrove loss around the world is running at 1 to 2 percent a year for the last 30 years. If we were to completely stop mangrove loss and start to reforest them, we would need to replant at a pace of 370,000 acres a year. At this point, Lewis notes, we aren't even keeping up with one hundredth of that level.
Photo by treesftf via Flickr CC
Rebuilding Mangroves, One Seed At A Time
That isn't to say that mangrove reforestation is a hopeless cause. Indeed, there is a great deal of possibility that we can return lost mangrove land to its former productive and helpful glory. There are several efforts in different places around the world that are worth of mention -- even one that earned a Guinness World Record.
"The current record of 541,176 mangrove propagules plated by a team of 300 people within a twenty-four-hour period was set in July 2009 by the Pakistan Ministry of the Environment," writes Warne. "That plantathon, on mudflats near the mouth of the Indus River, surpassed the previous record of 447,874, set a month earlier by an Indian army regiment in Assam. What next -- the Mangrove World Series?"
On a more consistent level, the reforestation project occurring on the shores of the Red Sea is noteworthy for those interested in restoring mangroves anywhere in the world. Gordan Sato is working to alleviate poverty by replanting mangroves. Through studying the needs of mangrove plants in the area, has come up with a smart replanting system.
He watched where the mangroves were growing -- since the trees only grow in very particular areas between the sea and land -- and figured out that the mangroves were seeking the minerals brought by freshwater from inland. Now, seedlings are planted with an open-ended tin can to keep them from washing away, as well as a piece of iron and a sealed plastic bag filled with diammonium phosphate fertilizer, that has a hole in the bottom to act as a drip system. While plastic and other buried "trash" is less than ideal, the use of plastic and cans solves a number of problems and has allowed the successful planting of nearly a million mangroves.
By paying attention to what the plants need and coming up with a low-cost solution, Sato is helping to restore an ecosystem that can feed and protect millions as it grows.
It is this kind of ingenuity, as well as being given a true market value for what mangroves provide, that will turn the tide and hopefully bring them back from the edge of extinction. In Let The Eat Shrimp, Kennedy Warne details the many, many ways that we need mangroves, and you will close the book feeling inspired to protect a little appreciated, but much needed habitat.
Join Kennedy Warne for a live discussion on August 25 at 3pm Eastern.
More Book Reviews on TreeHugger
Shark Week: Demon Fish Dissects Sharks' History, Future, and "The Greatest Scam of All Time" (Book Review)
4 Key Lessons Learned From The Death and Rebirth of Monterey Bay (Book Review)