COA AND CONSERVATION
Freshwater Mollusk Habitats
Often we think of the habitat
freshwater mussels live in as just 'water.' This is a very limited
view of their world. They actually live in a very dynamic habitat
which is closely tied to the habitats that surround it (the
stream banks, overhanging trees and surrounding lands). Often
this whole area is refered to as the 'riparian zone.'
Riparian zones are very fragile;
even minor alterations made by cows or all-terrain vehicles
can cause severe damage to the area. These small 'rips and tears'
in the fabric of the riparian zone allow runoff of silt and
pollutants from the land. Just as high levels of air pollution
make it hard for us to breathe the air; clouds of silt in the
water choke and smother aquatic animals. Along with the silt,
phosphorus, nitrogen, and other nutrients are washed into the
river. The fertilizers that help us to grow lush lawns also
provide algae in the rivers with nutrients - nutrients at elevated
levels that cause them to rapidly reproduce, creating noxious
algae blooms. In order to use the nutrients the algae must consume
more oxygen, making it even harder for the aquatic animals to
breathe.
In areas where the damage to
the riparian zone is severe, erosion turns the stream brown;
the lack of shade elevates the water's temperature; and both
oxygen and food become scarce. The aquatic animals must either
move to a more favorable part of the river or face starvation.
Every change to the riparian zone causes additional changes
downstream. Eventually these changes add up.
There are species of both freshwater
snails and bivalves currently on several countries' endangered
species lists. Almost all of these mollusks inhabit small, distinct
areas that have been severely altered. Most of the listed species
are our own freshwater mussels. They are so close but we know
so little about them. Follow the links below to see the information
we have gathered.
Freshwater mollusks links:
