Southeastern
US
The rivers and streams of the American Southeast are
unusually rich in aquatic biodiversity. They are home to such colorfully
named fish as the Pygmy Madtom (the world's smallest catfish), the
Halloween Darter, and mussels like the Tennessee Heelsplitter and
the Purple Wartyback. From the huge paddlefish and sturgeon to tiny
daces and shiners, these rivers and streams are of global significance
and home to freshwater mussels, fish and snails found nowhere else
in the world.
The rich biodiversity of the area has its roots in history. While
glaciers covered other parts of the temperate world during the
last Ice Age, they stopped just north of what is today the southeastern
United States. Plants and animals died from the prolonged freeze
in other regions, but the rivers and streams of the American Southeast
had a favorable climate for a long time, which allowed new species
to evolve and thrive. The result today is one of the most species-rich
river ecosystems in the world.
Rivers in this Southeast ecoregion begin as small streams in
the Appalachian and Cumberland Mountains, flow down across the
Piedmont, and meander across the Gulf coastal plains. This varied
geography contains a mixture of aquatic habitats that contribute
to the region's diversity of wildlife. The Tennessee/Cumberland
and Mobile Basins contain the greatest levels of fish and mollusk
diversity in the temperate world! About 90 percent of the mussels
and almost 73 percent of the aquatic snail species in the United
States are found here. The area's freshwater mollusk population
is also one of the world's most threatened. The Cahaba River,
which flows through central Alabama, carries within its waters
at least 131 fish species, including 18 that exist only in this
river. There are more fish species per mile in the Cahaba than
in any other North American river. And, recently, scientists discovered
that the Duck River, which flows though central Tennessee, rivals
the Cahaba in its diversity of fish species and its thriving mussel
populations.
More than 250 species of crayfish, nearly 300 species of mussels,
and over half of all freshwater fish species in the United States
are found in the waters of the Southeast. Many native species
are found in just one stream or watershed here and nowhere else
on the continent or the world. In addition to fish and mollusk
species, the Southeast's rivers and streams' varied freshwater
habitats also sustain numerous species of birds, mammals, reptiles,
and amphibians. Some of the better known species include: the
wood stork, North America's only stork; the river otter; the American
alligator; the ringed map turtle; and the alligator snapping turtle,
which can exceed 300 pounds and live more than 100 years. Also
found only in the area is the rare Tennessee cave salamander and
the Nashville Crayfish.
People, too, have been living near the southeastern rivers and
streams for at least 12,000 years. We have relied on them for
food, transportation, drinking water and spiritual solace. These
places have witnessed eons of human and natural history and are
testaments to the resilience of life on Earth.
People farm, use timber and build cities and towns, and in doing
so affect the rivers and streams they rely on for water. As more
people move into the region, the impacts on our freshwater resources
increase markedly. The rivers and streams of the Southeast are
the centerpiece of a way of life steeped in outdoor traditions,
from fishing and swimming to boating, playing, or resting on the
shady banks. However, runoff, water supply issues, suburban sprawl,
unchecked road construction, unsustainable agricultural and forestry
practices, dams, mining, and point source pollution threaten this
rich natural legacy and the aquatic life that live beneath the
region's waters.
These threats illustrate that freshwater conservation in the
southeastern United States is a complex issue. Yet, protecting
aquatic biodiversity from these threats also protects our own
water quality. Clean freshwater is critical to life on earth and
water quality is essential for all human communities.
Exercises
1. Look at a map of your area and see how many rivers you can
find.
2. What river is the closest to your school? To your house?
3. Organize a field trip to a nearby river, and see how many
animals, birds and other creatures you can identify. While standing
by the river, see how many threats to the river's water quality
you can identify just by looking around you.
4. Would you eat a fish caught in that river? Why? Why not?
|
