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To successfully manage ecosystems, a basic understanding of the system's biological components is mandatory. The biota respond to a wide variety of cumulative factors, both natural and anthropogenic. As the organisms integrate these factors over time, a characteristic community structure emerges. When human actions adversely affect a system, the biological population will change, leading to an imbalanced community. For example, pollution sensitive taxa will disappear, taxa richness and diversity usually decrease, food webs are disturbed, and undesirable nuisance species may dominate.

The Biological Assessment Subsection is responsible for the analysis of benthic macroinvertebrate communities. These data, along with several other aspects of the system (algal biology and community assessment, nutrient chemistry, physical/chemical attributes, sediment characteristics, toxicity, microbiological communities, habitat assessment, land use, and historical information), provide a multi-disciplinary approach to the evaluation of water quality.

DEP Programs That Utilize Biological Assessments

Fifth Year Inspection Program

Point source dischargers are required to renew their permit every five years. How does a permit writer know if a given discharge is environmentally acceptable or if more stringent permit restrictions are needed? Historically, they had to rely on fairly limited data, mainly provided by the permittee. For the past seven years, the Department has depended upon a highly successfully bioassessment program to provide additional information for permitting decisions.

A comprehensive study of the effluent and its effects on the receiving water biological communities is performed several months before the permit expires. Toxicity bioassays are conducted on the effluent, which is also analyzed for priority pollutants and metals. Benthic macroinvertebrates and algal communities are examined at a reference station (usually upstream of the discharge) and at a potentially affected station (located within the influence of the discharge). An objective habitat assessment is performed at both test sites to ensure comparability of biological sampling stations. Other parameters include fecal coliform bacteria, sediment analysis, algal growth potential, and nutrients.

The data are evaluated, using several measurements of community health, to determine possible violations of Florida Water Quality Standards. These include: biological integrity (diversity), imbalances of flora or fauna, dominance of nuisance species, toxicity, and individual chemical/bacteriological numeric criteria. A succinct report, summarizing the findings, is written and sent to appropriate regulatory staff, who recommend ways to correct any problems uncovered by the studies.
Bioassessments Reports

Forestry Best Management Practices (BMP) Program

Conducted in conjunction with the Florida Department of Agriculture and Consumer Services, Division of Forestry, this study was designed to determine the effectiveness of silvicultural best management practices. A minimum of six stream segments in four separate streams were sampled prior to logging activities, and again approximately one year later, after clear-cutting, site preparation, and planting had occurred. Several additional streams subject to silvicultural activities were sampled throughout the state, to determine overall success of BMPs.
Forestry BMP Studies

Basin-Wide Assessments

For these studies, biological, physical, chemical, and habitat information is collected from several stations throughout a drainage basin. The sampling sites are selected to assess the effects of human activities in the watershed, which may include point source discharges or stormwater inputs from urban or agricultural areas. The results may be used for permitting, compliance, or ecosystem management purposes.
Basin Study Summaries

Mitigation Studies

The practice of environmental mitigation, which involves human restoration or creation of aquatic systems, has increased in recent years. The former Bureau of Wetlands Resource Management had developed various compliance criteria for mitigation activities associated with specific dredge and fill permits, however, assurance that these criteria were sufficient for the re-establishment of healthy biological populations at the affected sites was largely unavailable. The Biology Section conducted three studies (sampled between 1991 and 1994) to evaluate the success of various created wetlands and stream restoration activities.
Mitigation Study Summaries

Florida TMDL Studies

The Clean Water Act, Section 303(d), requires states to identify impaired water bodies and develop a wasteload allocation known as a Total Maximum Daily Load (TMDL) to reduce pollutants to a level sufficient to protect water quality of the system. The Department has gathered data from numerous sources to develop and prioritize a list of these impaired water bodies. Due to the limited data available for many systems, additional study was requested, to refine the list and more accurately determine the systems where a full TMDL study was needed.
TMDL Study Summaries

Marine Bioassessment Program

The Florida Estuarine and Marine Biological Assessment Methods-Development Program has completed the initial series of technical workshops. The files below contain the results of the workshops to date. From these workshops came proposed measures of community health for different habitats and the proposed methods for sampling those measures. Field trials to test those methods and measures are under development.

  1. Overview of status of DEP bioassessment methods-development program and estuarine/marine technical workshops to date. overview.pdf (PDF, 14kB)
  2. Report from habitat-based bioassessment workshop held April 1999. habitatrpt.pdf (PDF, 1.5 MB)
  3. Summary and overview report for indicator-group workshops held fall 1998. Individual workshop reports are below. summaryrpt.pdf (PDF, 10 kB)
  4. Report from corals bioassessment workshop held October 1999. coralrpt.pdf (PDF, 25 kB)
  5. Report from submerged aquatic vegetation (SAV) bioassessment workshop held October 1999. savreport.pdf (PDF, 24 kB)
  6. Report from benthic macroinvertebrate bioassessment workshop held November 1999 invertrpt.pdf (PDF, 29 kB)

Last updated: February 04, 2013

  Environmental Assessment and Restoration
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2600 Blair Stone Road M.S. 6512
Tallahassee, Florida  32399-2400
850-245-8077 (phone)
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