The threats
The wonder of wetlands
The designation in 1995 of Hong Kong's Mai Po Marshes as a wetland of international importance under the Ramsar Convention* did not come a moment too soon. Under constant threat from housing and land development, a myriad of infilling schemes, pollution from sewage, new industry, and even livestock waste, the marshes will now be the focus of international attention. Already, a Sino-Hong Kong environmental liaison group is studying how to improve the management of the marshes, and a joint water quality research project is under way. This may, however, be an example of "too little, too late".
Mai Po is a mirror of the degradation suffered by wetlands the world over. Commercial development, drainage schemes, extraction of minerals and peat, overfishing, tourism, siltation, pesticide discharges, and the construction of dams and dikes routinely kill or damage wetlands everywhere. In the Philippines, a staggering 80 per cent of coastal wetlands have been drained, degraded, or destroyed in just 30 years.
Military action, too, can be a significant factor in wetland decline. Exercises frequently cause immense damage, while wars create the kind of havoc to people and the environment that is being witnessed in the marshes of southern Iraq.
Climate change - "global warming" - is also taking its toll. This phenomenon, coupled with the fact that the planet is still in a post-glacial phase, is causing polar ice to melt and sea levels to rise. This in turn is leading to shallow wetlands being swamped and some species of mangrove trees being submerged and drowned. Some scientists forecast that climate change will lead to the disappearance of entire island nations.
Yet at the same time, other wetlands - estuaries, floodplains, and marshes - are being destroyed through drought. There is still much to be learned about weather patterns and climate change.
Another major cause of wetland loss is human overexploitation of the underground water table for agriculture, housing, industry, and tourist development. In all too many places, the amount of water being taken from nature's underground aquifer is far outstripping its ability to replenish itself - the result being that as the water level drops, millions of trees and plants are dying because they are deprived of their life-sustaining supplies.
* see pages 18 and 19
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