RNR 1001 Lecture : RNR Lecture 10 04 2013
Document Summary
Colonial america 221 million acres in the lower 48 states,, 171 million in alaska. Between 1870 and 1980 alaska lost <1%, but the lower 48 states lost about 50% Wetlands reduce the severity and frequency of flooding - -4 billion in annual losses. Increases slow infiltration and percolation of water to recharge aquifers. Access to riparian wetlands reduces bank erosion, stream bed scouring, also provides temporary habitat for some organisms from the stream. Loss of riparian wetlands has changed the way rivers and streams function. Many riparian wetlands have been destroyed by levees. Without lateral movement during storms,, downstream flooding becomes much worse. Wetlands trap sediments, reducing turbidity and building terrestrial systems. Many pollutants,, particularly organic pollutants are degraded in wetlands by bacteria. Constructed wetlands have been used to treat effluents: Waterfowl production 60-70% of north american ducks breed in the prairie pothole regions. 2. 5 million mallards and all wood ducks winter in flooded southern bottomland hardwood swamps.
