Qatar's Mangrove Forests
The Grey Mangrove
Qatar is home to the Avicennia Marina, also known as the grey mangrove or white mangrove tree, communities of which form several forests around Qatar's shores. These mangrove swamps are home to a wealth of life, including a new species of sea slug that was found in 2007 by a member of the Qatar Natural History Group.
The largest area of mangroves - and the oldest - can be found around Al Thakira and Al Khor. Other mangrove areas in Qatar originate from fairly recent plantings by the government, although unfortunately the picturesque mangrove lake in Al Wakra has now been uprooted.
Surviving in the Mud Flats
You'll notice from the picture to the right that mangrove roots radiate out from a central plant. From these roots small shoots grow up to feed on the nutrients in the mud. This radiating root system helps the mangrove plant maintain stability in the shifting mud.
These radiating roots are also a way of dealing with a lack of oxygen in the mud below them. In fact, as you walk on the mud in mangrove swamps you will smell a strong smell of sulpher as your feet sink into the ground. You are in fact smelling hydrgoen sulphide, which is produced by the bacteria which lives without light or oxygen below the surface of the mud.
From the roots of the mangroves small snorkel-like growths protude upwards. These are called pneumatophores, or "bearers of air", and enable the mangroves to get oxygen directly from the air above the mud.
To cope with reproduction in these difficult conditions, mangroves are viviparous - they have "live birth". Mangrove fruit does not drop off the tree but becomes seeds on the plants. The seeds stay on the tree, storing nutrients and germinating while still on the plant. When they drop off they are ready to grow, although they can float on water until they find an appropriate place to take root.
Mangroves are adapt at surviving in salty conditions that kills other plants, managing to exclude much of the salt at their roots. However, the grey mangrove is also particularly adept at excreting salt. Their leaves contain special glands which concentrate the salt and remove it onto the surface of their leaves. If, during a trip to a mangrove forest, you lick the leaf of a mangrove plant, you should be able to taste the salt.
According to Field Guide to Mangroves, the plants can grow as high as 10 metres tall in countries such as Australia while Know Your Mangroves maintain that they can can range from half a metre in height up to a massive 25 metres. However, the plants in Qatar have to deal with a very high level of salinity, which stunts the growth of even the salt-resistant grey mangrove, and mangroves in Qatar grow to nothing like this height.
Use of Mangrove Swamps
In the past mangrove trees in the Gulf were used in the construction of houses, boats and furniture. They were also used extensively in the production of charcoal, and carbon dating of former charcoal hearths provides evidence of charcoal production dating back at least 4000 years in Qatar.
Mangrove forests also provide grazing for camels, which not only have no trouble eating the so-called inedible leaves but actually enjoy them. In the past, Bedouin nomads believed that these leaves conveyed strength to their camels.
Mangrove swamps and the Environment
Mangrove swamps have several advantages for the environment. Perhaps most importantly for a low lying country like Qatar is their ability to prevent coastal erosion. When sediment is washed in by the sea, it is deposited around the trees and does not wash out again.
In other areas of the world mangrove swamps have been successful in protecting coastline against the effect of tsunamis and hurricanes. In fact, mangrove destruction prior to the 2004 Asian Tsunami contrinuted to the huge loss of lives and property, while areas where mangroves had not been destroyed saw far less destruction. (See Tsunami: Mangroves saved lives for more information.)
Mangrove swamps also have their own unique eco-systems, providing a refuge for a wide variety of wildlife. In fact, mangrove trees can provide a huge amount of energy in the form of biomass. According to Fish Care - Our Mangrove Forests a square kilometre of mangrove forest can provide as much as 600 tonnes of material per year. While the stunted trees of Qatar are unlikely to produce this much food, their importance in an otherwise very barren country can't be underestimated.
The mud around mangrove swamps holds a wealth of organisms, and the numerous holes you will see in mangrove swamps are home to crabs and other herbivores such as molluscs, shrimps, small fish and other herbivores. After the hard-to-digest mangrove leaves have been broken down by bacteria, these creatures munch away at the mangrove leaves and the fungus that grows on them, turning it into nutritious mud attractive to other bottom feeders.
All the small wildlife in the mangroves leads to predator species coming, and mangroves provide great breeding grounds for a variety of fish. In particular, mangrove swamps provide a safe breeding ground for young fish to grow, and countries where mangrove swamps have been destroyed have seen a corrolating loss in fish stocks, including commercial species.
Not all the decomposing matter is consumed in the swamps - much of it is carried out into the open sea where it provides food for plankton. These in turn are eaten by prawns and small fish which are in turn eaten by larger fish. The fish life in turns attracts birds such as herons and egrets, which use the mangrove swamps for nesting and feeding.
The swamps also attract one more visitor - us! The variation of the landsape from scrub desert, and the huge variety of wild life that we can experience there, make for a fascinating weekend visit. One of the best ways to visit them is on a Qatar Natural History Group tour, and the group will be sure to provide you with a wealth of expert knowledge to accompany your trip.
An Introduction to Qatar's Natural History by Frances Gillespie