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what are wetlands?

The Convention on Wetlands of International Importance or RAMSAR Convention defines wetlands as

"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" (Article 1.1).

The Convention text also stipulates that wetlands:

"may incorporate riparian and coastal zones adjacent to the wetlands, and islands or bodies of marine water deeper than six metres at low tide lying within the wetlands, especially where these have importance as waterfowl habitat." (Article 2.1).

Wetland types may be classified into coastal and freshwater wetlands. 

  • Coastal wetlands include coral reefs, seagrass beds, estuaries and mudflats, and mangroves. 
  • Freshwater wetlands include lakes, swamps and marshes, peatlands, river basins, reservoirs and dams.

Wise use of wetlands is the maintenance of its ecological character, achieved through the implementation of ecosystem approaches, within the context of sustainable development. Ecological character is the combination of the ecosystem components, processes and benefits/services that characterize the wetland at a given point in time.

The Convention on Wetlands texts
(as amended in 1982 & 1987)

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importance of wetlands

          Wetlands are part of our natural wealth and have been critical to the development and survival of human communities.  The advancing technological skills of human communities may seem to have supplanted the role of Nature, but recent environment catastrophes - floods, landslides, storms, many with their roots in unsustainable land use practices - suggest otherwise. 

   Ninoy Aquino Parks and Wildlife Nature Center  

the many functions of wetlands -


Wetlands often play a crucial role in flood control.  Loss of floodplains to agriculture and human habitation has reduced this capacity. 

Construction of levees and dams on rivers to improve flood control have often had the reverse effect.

Floodplain restoration and removal of structures in providing a partial solution in many countries.

human habitation at river banks


Plants and soil in wetlands play a significant role in purifying water.  High levels of nutrients such as phosphorous and nitrogen, commonly associated with agricultural run-off, are effectively removed by wetlands.  This is important in preventing eutrophication further downstream, a process that leads to rapid plant and algal growth followed by depleted oxygen levels that affect other species.

It can also be important in preventing high concentrations of these nutrients reaching groundwater supplies or other water sources that may be used for drinking water.


Wetlands, in general are home to a great diversity of species.   Although freshwater wetlands cover only 1% of the Earth's surface, they hold more than 40% of the world's species and 12% of all animal species.

On the marine front, coral reefs are among the most biologically diverse of the land ecosystems.  Although they cover only 0.2% of the ocean floor, coral reefs may contain 25% of all marine species. 

The biodiversity in wetlands is also valuable as a reservoir of genes.  Rice is a common wetland plant and the staple diet for over half the world's population.

Some wetlands contain significant numbers of endemic species.



Many wetlands are prime locations for tourism, and some these sites generate considerable income locally and nationally.

Recreational activities such as fishing, hunting and boating, involve millions of people who spend money for these activities.

Wetlands offer ideal locations for involving the general public and schoolchildren in hands-on learning experiences, in an essentially recreational atmosphere, to raise awareness of environmental issues. 

.... students doing water quality sampling

Although largely an unexplored, poorly documented subject, wetlands are frequently of religious, historical, archaeological or other cultural significance at the local or national level.

Fluvial Procession on the river at the Feast Day of the Lady of Peņafrancia
photo by Larlina Parrone

In a preliminary survey of Ramsar sites, over 30% of a sample of 603 Ramsar sites recorded some archaeological, historical, religious mythological or cultural significance. 


An aquifer is a layer of rock containing water.  Underground aquifers store 97% of the world's unfrozen freshwater, and they provide drinking water to almost a third of the world's population.  Many wetlands help recharge these underground aquifers.

Groundwater is the only source of water for many irrigation programs - 17% of the world's cropland is irrigated.

Batlag Falls in Tanay, Rizal


Wetlands tend to slow down the force of water, encouraging the deposition of sediments carried in the water.  This is beneficial further downstream where deposition of sediments may block waterways.  Nutrients are often associated with sediments and can be deposited at the same time. 

Nutrient retention in wetlands makes them among the most productive recorded, rivaling even intensive agricultural systems.

Coastal deltas are dependent on riverine sediments and nutrients for their survival; engineered structures that interfere with the natural movement of sediments and nutrients can degrade deltas.


Storm surges and other coastal weather disturbances can cause immense damage through flooding and direct destruction of property, not to mention the loss of human life. 

Mangroves, marshes, and other coastal wetlands act as the frontline defense against incoming storms.  They help minimize the impact of storms by reducing wind action, wave action and currents, while the roots of the plants help to hold the sediment in place.

... mangroves in Coron Island, Palawan


Wetlands may store as much as 40% of global terrestrial carbon; peatlands and other forested wetlands are particularly important carbon sinks.

Conversion to agricultural use and destruction of wetlands will release large quantities of carbon dioxide, the gas that accounts 60% of the global warming effect.


Wetlands provide a variety of other benefits in the form of products that can be exploited for human use.  The range is enormous: fruit, fish, shellfish, crocodile and other meats, timber for building, rice, fuelwood, fodder for animals, etc.

Exploitation is carried out in all levels - subsistence level, cottage industry, and the larger commercial scale - in all parts of the world.


   |   organization   |   activities  |   wetlands  |  philippine wetlands  | 

Unit 208, Grand Emerald Tower
F. Ortigas Jr. cor Garnet Sts.
Ortigas Center, Pasig City, Philippines
Tel/fax (63)(2) 637-2409
email: wetlands@psdn.org.ph

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