Biol 333: Lecture 3 World Wetlands

Where are wetlands concentrated in the world?

~9% of global land area is wetlands; most occur at 0 and 60 degrees lat

What are the most prominent kinds of wetlands?

• Northern Peatlands represent ~30-50% of global wetlands

• Tropical swamps are the second largest wetland category

What are some examples for why wetlands have been lost?

• Many prairie potholes in Alberta have been drained for agriculture

• Riverine marsh Kankakee in Ohio; drained from channelization of the river; same in Toronto with River Don straightening → leading to immense flooding

• Conversion of deltas into rice paddies in Asia

• Dykes along coastlines in the Netherlands; loss of coastal wetlands

• Drainage for forestry 

What crops have been cultivated in wetlands? why?

• Cultivation of sugar cane, yams, vegetables and rice

• Wetlands have more reliable water availability

What are some cities tht have been built on wetlands?

• St Petersburg

• Paris

• London

• Berlin

Are wetlands being lost worldwide? at what rate? why?

Global Wetland Loss

Has increased 20% since 1970; rate is slowing (or reversing?)

Very pronounced in the United States (53%), Asia and Europe (60%)

Mostly due to Cropland (rice) and Urban development

What are the important wetlands in Canada?

• North Slope

• Peace-Athabasca Delta

• Prairie Pothole region

• Hudson Bay Lowlands