Geoscience Reference
In-Depth Information
Figure 1-1.
Padre Island National Seashore, southern Texas, United States. View northward showing Padre Island
(left) and the Gulf of Mexico (right). More than 70 miles (110 km) of island and beach are protected. Note person
standing at bottom for scale. Kite aerial photo by J.S. Aber and S.W. Aber.
regions. Upstream manipulations and exploita-
tion of wetland water resources have resulted in
serious degradation or dramatic changes lower
in drainage basins (Fig. 1-8). In contrast, some
exploitations of wetlands, for example pearl
farming, actually add marine life and provide
protected areas that are free from dynamite and
cyanide i shing. It is safe to say, though, that
few, if any, major wetland systems of the world
have not been altered or changed in substantial
or subtle ways by human activities.
Wetlands are situated at the transitions
between dry uplands and deep-water lake and
marine environments (Fig. 1-9). Wetlands, thus,
may be viewed as the links that bind together
all other habitats at the Earth's surface, and they
play key roles in the overall environmental
system through transfer and storage of materials
and energy. Numerous feedback relationships
exist between wetlands and their surroundings.
Figure 1-2.
Hippopotamus (
Hippopotamus amphibius
)
displays its formidable jaws and teeth in a marsh of
the Okavango Delta, Botswana, southern Africa. Photo
courtesy of M. Storm.
