Wetlands are endangered by human activities such as draining, farming, water flow diversion, dam building and recreational activities. At one point, it was believed that wetlands needed to be drained. This action reduced wetlands in the United States by about half, and they have not been restored [source: Zinn].
Other threats to wetlands include overabundant wildlife and weather disasters such as floods, droughts and hurricanes. All of these can do irreparable damage to these fragile environments.
Global warming and pollution are an added threat. Global warming can increase water temperature and encourage red tide. Pollution can run off dry land during rain and poison water.
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