Mangroves are slat tolerant bush type trees which grow in inter-tidal zones of tropical and subtropical areas, river deltas and along the coasts. There are some 15.9 million hectares of mangrove forests all over the world. They are of great economic and environmental importance.
Those living near Indus delta and Karachi might have seen that mangrove trees look different. The have special aerial roots which hold the trunk, leaves and foliage above the water surface. The aerial roots and tap roots can filter out the salt in the brackish water they grow in. Support roots grow directly into the mud to anchor the tree. Other roots wind up and down with the upward loops rising above the salt water level. Salt crystals taken up by the roots are stored in the leaves. The mangrove tree rids itself of the salt by shedding its leaves after sometime.
Mangroves forests of Pakistan in Indus delta and along Arabian Sea coastal areas, as per estimates, are some 129,000 hectors in the Indus delta and over 3,000 hectors in Miani Hor, Kalmat Khor and Gwadar bay areas.
Mangrove forests are teeming with life. They are natural habitat to a large number of insects, micro organisms, birds, different mammals as well as snakes. Mangrove areas act as physical breeding grounds and nurseries for fish, shrimp and crabs. During winters, many guest birds from north also come to breed here. The mangrove forests protect the coasts from dangerous cyclones and hurricanes. Mangroves slow the water’s flow, helping to protect the coastline and preventing erosion. They also reduce sedimentation in the sea. Over time, the roots can collect enough debris and mud to extend the edge of the coastline further out. Hundreds of thousands of people directly of indirectly depend on the mangrove ecosystem for living. For centuries they have been used by human being for getting fuel wood fodder for the animals. Over the last five decades, mangrove forests in Pakistan has been subject to over exploitation and massive population pressure, and are therefore deteriorating fast in the quantity as well as quality.
Without realizing the global significance, mangroves are being cut mercilessly. Near urban areas, mangroves are cleared for developmental activities. Reduced water flow in the River Indus – sixth largest river in the world — after the construction of dams and barrages upstream is also causing damage to mangrove forest and ecosystem they support.
Mangroves need to be managed and conserved. Concerned agencies, government departments and non governmental organisation have already started taking steps and visible efforts are being made in this regards: New mangrove nurseries near Karachi, some other projects to grow more forests and mobilization of the local communities by enhancing awareness on the significance of mangroves for livelihood and by persuading them to take responsibility for conserving mangroves.
To stop the degradation of mangrove areas, the World Bank, back in 1999, had suggested that the mangroves forests in Pakistan be protected by declaring the Arabian Sea coastal areas a national park. This sort of sustainable solution will have important effects on the environment in the longer run.