Mangroves was once considered wasteland but they are the nurseries of shrimps and protect the land from erosion and weathering. -- FIle Photo

These forests serve an important socio-economic purpose providing sustenance not only to humans but also to marine and bird species in the ecological habitat, writes Sachal Abbassi

There may be no holiday more pleasant than one spent in a tropical sea coast drinking coconut juice in a plenty of warm sunlight while enjoying eating a deliciously fresh fish.

The coastal scenery is one to indulge in with its mellow sea breeze softly massaging the skin as one sets eyes upon everything nature has to offer in a heavenly lush sea coast resort. One thing in particular, which one experiences during such a holiday, is the lavishly green mangroves growing underneath surface water of swamps.

Typically, the eco-regions of mangrove trees include most tropical and subtropical regions on the planet, ranging between the latitude of 25° North and 25° South. They can be found in the creeks of the New Guinea River of the western pacific, South Africa’s Nahoon River and even in the Caribbean coast of Mosquitia-Nicaraguan.

Their global outreach has resulted from their ability to easily adapt to different tropical environmental and climatic conditions, including different levels of water salinity, temperature, evaporation rate and tidal variability amongst others.

Biodiversity within the species is impressive, and there are at least 110 known different tree species of mangrove which can grow in saline water near creeks and deltas. As pleasing to look at or impressive their global pervasiveness may be, virtues of the mangroves extend far beyond their charm.

These forests serve an important socio-economic purpose providing sustenance not only to humans but also to other species in the ecological habitat. Marine and avian species at different levels of the food chain use mangrove for a variety of survival and breeding purposes, and the bio-ecological link between these species and mangroves is irreplaceable.

Unfortunately, like most other wooded areas, human activity is taking its toll on these forests and their global spread is sharply declining, which poses a challenge for environmental groups, policy making and the general public alike.

Forestry Department of Food and Agriculture Organisation of the United Nations, (UNFAO) estimated that total mangrove area in the world to be 15.6 million hectares, while a more recent estimate suggests that it may be as low as 12 million hectares.

Alarming as these numbers may be, they do not represent the loss of biodiversity of the mangroves, which is leaving the fittest of the mangroves to survive, while those species more vulnerable to environmental and climatic changes are endangered. Global reduction of the mangroves is resulting from exponential industrialisation of the coastal areas, which is pushing the demand for development and natural resources.

Water pollution and deforestation for land reclamation purposes are among important reasons for international endangerment of mangrove’s biodiversity and survival.

In Pakistan, similar factors and others are leading to its deforestation which is posing a threat to the natural environment and climate of mangrove regions. Most of the mangroves here are found near the Indus Delta, where four types of mangrove species exist but Avicennia Marina dominates the region.

Tragically, a lot of mangrove covered region lies in and around Karachi, a commercial and industrial hub. As a result, some of the deforestation has been caused by industrialisation and growth of the city. A lot of mangrove covered land is reclaimed for commercial uses, and as such the trees are chopped off at unsustainable rates. Wood gathered from deforestation is sold for construction and other commercial uses and at times, the need for wood alone is an enough ground to axe a tree.

Other threats to mangrove survival arise from on-going water pollution resulting from industrial activities. This is changing the chemical composition of water adding metallic and toxic waste to it, which is undermining the survival of other species living in the habitat. Oil spills from ships and dumping of the city’s waste into the sea is also contributing to water pollution, which is slowly making life difficult for the trees which once dominated these regions.

Perhaps, most important reason for mangrove deforestation is the disruption of fresh water flow from the Indus River caused by building of water reservoirs. Due to highly saline water coming ashore into the delta, physiological adaptation becomes difficult and it is common for mangroves to suffer stunted growth or even death.

An increase in salinity is depriving the trees a fair chance of survival, even in the midst of ongoing water pollution. With the current levels of unsustainable activities, a time may come when loss of mangroves will be irreversible.

In 1965, a survey by Pakistan Forest Institute concluded a staggering 400,000 ha covered by mangroves, but by 2001, this figure was reduced to 158,000 ha. These figures are a cause for alarm and it is high time policies were put into place to salvage and safeguard the mangroves.