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

  RESERVOIRS OF BIODIVERSITY

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.

  RECREATION / TOURISM

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. 

  CULTURAL VALUE

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

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.

  SEDIMENT & NUTRIENT RETENTION AND EXPORT

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.

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, 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.