The riverine and mangroves forests in Punjab and Sindh province have been degraded due to deforestation and non-availability of fresh water in the sea. An official said, during the past two decades, there had been a significant deforestation in natural forests of Gilgit-Baltistan and Khyber Pakhtunkhwa. However, tree cover on farmlands and private wasteland had significantly increased during the period. Since Forestry was a provincial subject, the federal government has been supporting this sector through national policies, capacity building and trainings, implementation of international agreements on forests and sponsoring of forestry sector development programmes. After 18th Amendment, these functions of federal government have been transferred to Ministry of Climate Change.
The official further said despite the importance of forests in the life of common people, its contribution in the national economy is negligible 0.2 per cent whereas the country’s 5.2 per cent of total land area is under forest cover. A growth rate of 1 per cent has been observed in fiscal year 2011-12 while 2 per cent is a growth target for current financial year 2012-13.
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.
Threats to mangrove forests and their habitats include:
n Clearing: Mangrove forests have often been seen as unproductive and smelly, and so cleared to make room for agricultural land, human settlements and infrastructure (such as harbours), and industrial areas. More recently, clearing for tourist developments, shrimp aquaculture, and salt farms has also taken place. This clearing is a major factor behind mangrove loss around the word.
n Overharvesting: Mangrove trees are used for firewood, construction wood, wood chip and pulp production, charcoal production, and animal fodder. While harvesting has taken place for centuries, in some parts of the world it is no longer sustainable, threatening the future of the forests.
n River changes: Dams and irrigation reduce the amount of water reaching mangrove forests, changing the salinity level of water in the forest. If salinity becomes too high, the mangroves cannot survive. Freshwater diversions can also lead to mangroves drying out. In addition, increased erosion due to land deforestation can massively increase the amount of sediment in rivers. This can overcome the mangrove forest’s filtering ability, leading to the forest being smothered.
n Overfishing: The global overfishing crisis facing the world’s oceans has effects far beyond the directly overfished population. The ecological balance of food chains and mangrove fish communities can also be altered.
n Destruction of coral reefs: Coral reefs provide the first barrier against currents and strong waves. When they are destroyed, the stronger-than-normal waves and currents reaching the coast can undermine the fine sediment in which the mangroves grow. This can prevent seedlings from taking root and wash away nutrients essential for mangrove ecosystems.
n Pollution: Fertilizers, pesticides, and other toxic man-made chemicals carried by river systems from sources upstream can kill animals living in mangrove forests, while oil pollution can smother mangrove roots and suffocate the trees.
n Climate change: Mangrove forests require stable sea levels for long-term survival. They are therefore extremely sensitive to current rising sea levels caused by global warming and climate change.
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.