| |
|
Wetlands and climate change
As a frontier-type ecosystem, wetlands are particularly vulnerable to climatic variation and extreme events. Many wetlands, especially coastal ones, are unstable to start with, and are easily or frequently changed by erosion, flooding, or the invasion of salt water.
But water supply is the main concern. In arid and semi-arid areas, the occurrence of hotter, drier summers and the increased use of water for irrigation could reduce the supply of water for wetlands, either directly or indirectly (through the effect on the water table), or both. A lower volume of water would increase the concentrations of the pollutants that tend to settle in wetlands (agricultural chemicals, naturally occurring salts, atmospheric pollutants).
Small changes in temperature or water supply could have significant effects on wetland biota. A rise in temperature could allow an undesirable plant species (purple loosestrife, for example) to expand northward. High temperatures and low concentrations of oxygen favour the growth of the botulism bacterium. A change in the seasonality of precipitation could harm plants or animals whose life cycles require certain amounts of water at specific times of the year. Such a change could cause a decline in a plant on which waterfowl depend.
|
Wetlands Menu
Previous
