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HUMAN IMPACTS TO MINNESOTA WETLANDS
Citation:
Johnston, C. HUMAN IMPACTS TO MINNESOTA WETLANDS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-89/519 (NTIS PB91183160).
Description:
Minnesota's 3.6 million ha of wetlands have been impacted by a variety of human activities, including agricultural drainage, urbanization, water control, and nonpoint source pollution. ore than half of Minnesota's wetlands have been destroyed since the first European settlers arrived, an average loss of about 35,600 ha/yr. rainage for agriculture is the major cause of wetland loss in Minnesota, particularly in southern Minnesota and the Red River Valley. n addition to impacting wetlands directly, wetland drainage affects downstream areas by increasing flood flows, and releasing sediment and nutrients. rban development and highway construction affect a smaller proportion of Minnesota's wetlands, but substantially alter their physical, chemical, and biological properties. ydrology has a major influence on the structure and function of wetlands, so changes in the frequency, duration, depth and timing of wetland flooding can severely impact wetlands. hile wetlands can assimilate low levels of sediment and nutrient enrichment, excessive inputs can be detrimental. eat harvesting is not currently extensive in Minnesota, but could cause substantial impacts. umulative impact, the incremental impact of an action when added to other past, present, and reasonably foreseeable future actions, is becoming an area of increasing concern.