What is the key concept for this section? What are four major ways in which human activities are disrupting and degrading freshwater systems? Describe losses of inland wetlands in the United States in...

What is the key concept for this section? What are four major ways in which human activities are disrupting and degrading freshwater systems? Describe losses of inland wetlands in the United States in terms of the area of wetlands lost and the resulting loss of ecosystem and economic services. Explain how the building of dams and other structures on rivers can affect the river deltas and associated coastal wetlands. How do these effects in turn threaten human coastal communities?