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WHAT HAPPENS
WHEN WETLANDS DISAPPEAR?
Flooded basements
in the spring. Entire downtowns inundated. Millions of pounds of
soil washed downstream, destroying farmland, fisheries, and food
for wildlife.
Whether it's
localized flooding or catastrophes such as the Midwest floods of
1993, the entire United States is at risk from increased flooding
due to our destruction of wetlands.
The Army Corps
of Engineers has studied the causes of flooding, and advocates wetlands
protection as the most cost efficient way to prevent flooding. For
example, Florida and Louisiana were both hit directly by Hurricane
Andrew in 1992. Florida suffered ten times the destruction. The
difference? Louisiana had retained more of its coastal wetlands.
Small-scale
wetlands destruction can also have far-reaching effects. As they
disappear, so to do their abilities to recharge groundwater, collect
sediment, and trap pollutants. In addition, isolated wetlands often
serve as crucial habitat for small populations of rare birds, insects,
and amphibians. For example, only a few whooping cranes nest at
Gray's Lake National Wildlife Refuge in eastern Idaho. But if irrigation
drew down the water table enough to dry up even portions of this
wetland, the crane's nesting success could be threatened by predator
access or other problems associated with the diminished wetland.
Agriculture
and urbanization have devastated the wetlands of California's Central
Valley. In previous centuries, this huge valley's wetlands supported
40 million waterfowl. Today, it supports only 8 million waterfowl,
with simultaneous reductions in recreation, hunting, and fishing
associated with this habitat.
The impact of
wetland destruction occurs far beyond what we can see. Aquatic invertebrates
are primary consumers in many aquatic ecosystems: they consume algae
and other organic matter, and subsequently become food for other
types of invertebrates and vertebrates throughout the food web.
Some species are found only in a few springs or streams; their loss
could ripple out far beyond their isolated wetlands.
The loss of
small, seemingly insignificant wetlands accumulates problems no
matter where they are. For example, in urban areas, many construction
crews ignore or are unaware of seasonal stream channels and ponds.
They fill the depression in the ground without considering the cumulative
impact of this landscape alteration. But the subsequent home or
business owners will have to deal with the flash floods, wet basements,
and inundated parking lots.
Downstream
water quality begins to suffer, too, and affects life from the microscopic
to the megafauna.
So what are
we to do? Learn to live with more floods, less water, fewer fish?
Maybe not. In Chapter Five, you'll find out about laws and people
protecting wetlands.
Will our children
be able to spend quiet fall mornings hidden among the tall grasses
of wetlands, watching one of the wonders of the natural world-the
autumn migration of ducks and other waterfowl? In this chapter,
you'll read about people, projects, and laws that are creating a
positive answer to this question.
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