‘Areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing,fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six metres’ (Convention on Wetlands (Ramsar, Iran, 1971), popularly known as the Ramsar Convention).
In tropical areas such as Malaysia, wetlands include swamps and marshes, lakes and rivers, peat swamps, swamp forests, floodplain, estuaries, deltas and tidal flats, near-shore marine areas, mangroves and coral reefs, and human-made sites such as fishponds, rice paddies and reservoirs.
In Sabah, wetland ecosystems are classified under several categories – saline and brackish wetlands (which include mudflats and mangroves), brackish wetlands (nipah swamps), freshwater wetlands (which include coastal lagoons, freshwater swamp forests, peat swamp forests, river floodplains, oxbow lakes and other natural lakes, mud volcanoes, riverine bank vegetation, and highland swamp forests), and, cultivated and artificial wetlands (such as open padang, sago, paddy, aquaculture ponds, dams and reservoirs). These ecosystems, both natural and man-made, all have important roles in sustaining man-kind.
Not so long ago, wetlands were mostly considered to be wastelands – uninhabited areas worthless for cultivation. This understanding has since changed, with the value of wetlands gaining increasing recognition. Diverse both in terms of their physical characteristics and their geographical distribution, wetland ecosystems play important functions, including as important habitat and nursery for plant and animal species, to protect from flooding and erosion, as a filter for pollution, as a producer of oxygen, as a major food source for humans and animals, and as a site for recreation. At the very basic level, this translates to sustaining the livelihoods of communities, as well as the survival of diverse wildlife dependent on it.
Although efforts have started to allow for the regeneration of wetlands in Sabah, either through natural growth or active reforestation efforts, areas are still being cleared for various purposes, such as development of commercial and residential areas. The decrease in wetland areas continue to occur due to the increase in demand for land.