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The single greatest threat to biodiversity in the U.S. and around the globe is the loss of natural communities to development and agriculture. Between 1992 and 1997 in the U.S. , 16 million acres of forest, cropland, and open space were converted to urban and other uses. Since the European settlement of North America , 27 different types of natural communities have declined by 98% or more in size. The destruction of previously intact ecosystems results in a loss of habitat for multitudes of species and breaks down an ecosystem's ability to function.
Poorly planned and sprawling development is a leading cause of habitat loss and thus biodiversity loss. Sprawl also exacerbates air and water pollution, both of which degrade environments and further reduce biodiversity. New construction often increases erosion of land cleared for development. This in turn increases stream siltation. As the land area for natural ecosystems shrinks, there is less natural capacity to filter pollutants and detoxify waters and less capacity to cycle nutrients and compost organic wastes. Thus, as sprawl increases, species and ecosystem services decrease. | 
