Many native species are uniquely valuable as indicators of environmental quality.
The rapid decline in bald eagles and peregrine falcons was a dramatic warning of the dangers of DDT - a potent, once widely used pesticide that accumulates in body tissues. In another example, certain plants, such as the eastern white pine, are particularly good indicators of excess ozone, sulfur dioxide, and other air pollutants. If it were not for species like these, we might not have known about the effects of some contaminants until more damage was done. All life on Earth depends on clean water to survive. While the decline of fish and freshwater mussel populations may seem insignificant to some, our human family also depends on those same waters for drinking, bathing, and washing clothes.