Bioassessment
of Florida's Aquatic Ecosystems
…using biological approaches to measure and evaluate
the consequences of human actions on biological systems
Florida's
Watersheds
Watersheds, or basins, are nature’s boundaries. They are
the land areas that drain to a waterbody. Florida has over
8,000 lake watersheds and 52 major river basins, each with
many smaller tributaries and their associated watersheds. Even
the smallest of Florida’s creeks represents the beginning of a
network of flowing waters that connect in a long, gradual
journey to the ocean. To improve the effectiveness of
Florida’s land and water resource management programs, and to
allow better assessment of the cumulative effects of all
pollution sources within a watershed, these programs are
currently implementing an integrated, cooperative watershed
approach. This approach allows better coordination of efforts
to control point and nonpoint sources of pollution, to
establish total maximum daily loads, to involve the public,
and to determine which mix of control strategies work best
within a watershed. Bioassessments play a major role in
helping to define problem areas and evaluate the effectiveness
of our pollution control efforts. Remember that "we all live
downstream" and that reducing nonpoint source pollution
requires all of us to be part of solution. If we all do a
little, we can do a lot to help assure future generations have
clean water.
Why
Study Biological Communities?
Biological
communities are sensitive to stress, both natural and
anthropogenic (caused by human activities). When our
actions adversely affect the environment, the biological
population will change, leading to an impaired or
imbalanced community. Much like the "canary in the
coal mine," the response of aquatic insects to
changes in water quality gives us an early warning of
possible harm to a waterbody. Many common insects spend
their juvenile life within aquatic systems including:
dragonflies; mayflies; beetles; black flies; and
mosquitoes. These organisms show the effects of physical
habitat alterations, point and nonpoint source
contaminants, and cumulative pollutants over their life
cycle.
What
is a Bioassessment?
Bioassessments involve field sampling of aquatic biological
communities to characterize community structure (i.e.
diversity, pollution tolerance). They include measuring water
quality indicators such as dissolved oxygen, evaluating
habitat conditions, and determining the health of aquatic
insect communities. To determine the biological health of a
waterbody, we compare it’s characteristics to those of
communities across a human disturbance gradient. The system is
then evaluated with regard to it’s designated use to determine
if it has been negatively impacted by our activities.
How
Can the Results of a Bioassessment be Used?
Biological
monitoring allows us to directly assess waterbody health.
Most importantly, they let us assess the cumulative
effects of all activities occurring within a watershed.
These results can be used to establish baseline
characteristics for Florida’s streams, lakes, wetlands,
and estuaries; to characterize the overall condition of
watersheds; to identify potential problem pollutants; to
target more intensive diagnostic samplings; and to
support land use planning and management decisions. They
can also be used to evaluate the effects of management
programs on waterbodies and their biological communities.
Bioassessments also provide an excellent way of
prioritizing waterbodies for special protection,
restoration, or rehabilitation.
Bioassessments
in Action
The
Florida Department of Environmental Protection uses
bioassessments to assess the effectiveness of point and
nonpoint source pollution controls and to evaluate the
health of waterbodies. Bioassessments are currently used
in the following DEP programs:
Basin-Wide
Assessments- to evaluate watershed health
- Fifth
Year Inspections- to evaluate the discharge of
municipal wastewater treatment plants
- Forestry
Nonpoint Source Program- to evaluate the
effectiveness of forestry best management practices
(BMPs)
- Mitigation
Assessments-to evaluate the success of created or
restored aquatic ecosystems.
- Bioassessments
are also used as an educational tool in
citizen/volunteer monitoring programs to provide
basic information about watershed health.
For
more information please contact Devan Cobb at 850/245-8542 or
devan.r.cobb@dep.state.fl.us.
