Sustainable management of mangrove forests in Kenya

Anouk Verheyden-Gillikin


A protected mangrove forest in Mida, Kenya (above) contrasts sharply with the over-exploitation of the mangroves near Mombasa (below)


About 50 km south of Mombasa is a small village called Gazi. It is a coastal village. Many of the villagers are fishermen and live from whatever the sea brings them. Some villagers have a little garden and grow vegetables, which they sell in their shops in the village. The Swahili houses are typically constructed from a framework of mangrove wood filled up with mud and stones. The roof is usually made from dried palm leaves, but the richer families in the village have tin roofs. Gazi Main Street is an earthen road where chickens and goats run freely in front of the occasionally passing car. Women and children gather at the village wells to fill up their buckets with water.

Swahili houses in Gazi are made from a frame of mangrove wood, filled up with mud and stones


Above: Kairo loves the mangrove trees

Dr James Gitundu Kairo lives in Gazi and is in charge of the research projects conducted on the mangroves of Gazi. Kairo loves the mangrove trees. He first came to Gazi to study the mangroves for his masters degree program. The mangrove forest then was over-exploited: where mangrove trees once flourished, only a bare mud flat was left. Once the mangrove trees are removed, new seedlings will not easily grow. This is because the root system of the mangrove trees stabilizes the soil and decreases the water flow, preventing soil erosion.

Kairo managed to convince the villagers that if they want to have wood for their houses in the future, the mangrove trees they cut needed to be replanted. In the beginning of the 1990’s, with the help of the villagers, seedlings were collected from the mangrove forest. They were grown in a nursery for one year and then planted on the mud flat. Today the mangrove forest is beautiful. Apart from the trees being in neatly organized in rows, it is almost impossible to differentiate between the natural and the planted forest. At this moment, the plantation is still protected; no villager is allowed to cut the planted trees until Kairo’s study reveals enough information to prepare sustainable management plans for future restoration projects. Integrating the information of tree growth rates and rates of seed production and seedling establishment, Kairo will be able to calculate how many trees can be cut per year, without causing a negative effect on the mangrove forest.

Right: Kairo in front of the Gazi plantation


Despite the protected status, some trees have been illegally cut. Kairo tells me he thinks it might be some kids of the village who needed the wood to make a fence for their chickens but Kairo is not angry. He explains to me he cannot be angry: the villagers have been living here for centuries, they need the forest; this is their forest. Kairo tells me: “Ecologists always want to protect but, you can not protect when you do not take into account what the people need. They live here too, just like the trees. When the villagers cut the wood from the plantation, it shows that the plantation was successful. It shows we provided a renewable source of timber”. And that makes Kairo really happy.

The success of Kairo’s management plan is that he involved the community at every stage of the plan: first, by informing people about the importance of protecting and restoring the forest, second by involving the villagers in collecting and planting the mangrove seedlings, finally, once the research reveals the necessary data, the villagers will be able to enjoy and benefit from the restored mangrove forest. The lesson to be learned here is that sustainable management is truly a community effort. Only with the support and understanding of the members of a community can a sustainable management plan be successful.

Dr. James G. Kairo received his Master degree form the University of Nairobi and his Ph.D. from the Free University of Brussels, Belgium. He is now employed by the Kenya Marine and Fisheries Research Institute (KMFRI) in Mombasa.

Above: children in Gazi gather around Mama Sofi.


To read more about what mangroves are and why they are important, click here

A little more about mangroves…

Mangrove forests are fascinating ecosystems. The forests are located just at the edge between land and sea and, therefore, harbor both terrestrial and marine creatures. When the tide is low, the mangrove soil is exposed and swarms with mangrove crabs. Birds, monkeys and even warthogs often find refuge in the mangroves at low tide. However, when the tide comes in, the mangrove forest is flooded with seawater and with this water, also enters the fish, shrimp and so many other sea creatures. Somehow the crabs seem to know when the tide is coming in, even before the water reaches their burrow. They carefully put together a plug made of mud, retreat in their burrows and use the plug to close the entrance to their burrow.

Mangroves at high tide (above) and at low tide (below)

While the mangrove forest might at this moment sound like a perfect place for an afternoon picnic, it is in no way the romantic place of your dreams. First, it is not very easy to venture through the forest. Many mangrove trees have roots that instead of being completely below ground, partially stick out above ground. You don’t walk through the forest; you climb through the forest, so to speak. Second, the mangrove soil is very muddy, sometimes firm and sometimes really soft. Make sure to wear tight boots or you might lose them while trying to free your foot from sinking further into the mud. Third, the mangrove soil is quite stinky. Bacteria in the soil convert sulfate (found in high concentrations in seawater) into sulfides (which typically has a rotten egg smell). And last, if you managed to deal with all the above inconveniences, the many mosquitoes zooming around your head might just make you crazy. However, apart from that, I shouldn’t forget to mention that it is the place where I fell in love with the man that is now my husband (a fellow researcher). Mangroves can be quiet romantic after all, at least for a biologist.

My husband, David and myself in mangrove gear: compass, white t-shirts (fights of mosquitos), pants covering knees (for me, to prevent scars from sharp oyster shells), tight diving boots (perfect when sinking in the mud)


Mangrove crabs swarm the mangrove soils and are very entertaining

Since 1980, there has been an increased effort to protect tropical forests and in particular mangrove forests. However, many mangrove areas are still at risk of being destroyed. This is mostly due to the high population density of coastal regions: 50 % of the world’s population (that is more than 3 billion people) live within 125 miles of the world’s coast lines. This high population density negatively affects the nearby coastal ecosystems, including mangrove forests, sea grass beds and coral reefs. Huge mangrove areas have been clear-cut to provide nearby cities with wood or have been converted to large-scale shrimp farms. While these shrimp farms are very productive in the first few years, a rapid decline is usually observed from the fifth to seven year onwards. Farmers have to add nutrients, spend tons of money on keeping the water clean and add antibiotics to the water to prevent disease outbreaks. This becomes a costly business and in addition, the antibiotics are bad for the environment. The clear cutting of mangrove forests further leads to increased soil erosion and leaves the coast line with little protection against storms and tsunamis. Finally, mangroves play an important role in the life cycle of many fish and shrimp species, which come and lay their eggs in the shallow mangrove waters. The forest contains many nooks and crannies between the roots and tree stems where the eggs are protected from predators. Destruction of the mangrove forest has therefore often been associated with a decrease in the fish catch further at sea. The sustainable management of mangrove forests should therefore directly benefit fishermen and the fish industry.