what IS the importance of wetlands?

Answer 1

They hold a biodiversity that cannot exist elsewhere.
They absorb a lot of pollution.
They are natural buffers for flooding... remember the Mississippi floods a few years back? They drained all the swamps and the water had nowhere to go but.. everywhere.

Answer 2

Wetlands serve a host of important ecosystem functions and are valuable also to human society. Among the important ecosystem functions are that they are high productivity environments and are also often diverse. The high productivity also has important consequences to humans in that they tend to support a large number of consumers many of which have commercial value.

In addition to the commercial and recreational values, other important human society values are:
* Flood and storm buffers
* Pollution filters
* Sediment filters (regarding navigable waterways)

A recent assessment of the monetary value of our natural wetland ecosystems estimated them at US$ 14.9 trillion, fully half of the value of the estimated value of all terrestrial ecosystems, despite the fact that they only account for a small fraction of that total area (see reference below).

Answer 3

It holds alot of wildlife that can not survive without it and it is also a natural place for water to drain to so local towns won't get flooded