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Biological Assessments     Central District Highlights

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Biological Assessments


The biologists of the Central District Watershed Monitoring and Management Program (WMM) conduct various biological assessments of water bodies in the interest of TMDL development and ambient monitoring. All field activities associated with biological sampling and assessments are done in accordance to DEP's Biological Field Activities SOP (FS 7000). Field staff are evaluated annually to ensure compliance with prescribed methods. Certification requirements for biological assessments are maintained and updated as needed.  





Biologist using dipnet








Helgramite observed during BioRecon



BioRecon is the screening tool version of the Stream Condition Index (SCI)- intended to rapidly assess a site to prioritize it for more intensive sampling. The SOP for Performing BioRecons varies from that for a Stream Condition Index (SCI) sample in that only four dipnet sweeps of the most productive habitats are performed. A Biorecon also differs from an SCI sampling effort in that the organisms are sorted in the field and then identified in the lab. Although the BioRecon protocol only dictates that relative species abundance be recorded on the BioRecon Field Sheet, samples of each taxa found are verified in the laboratory. Regionally based thresholds specific to this method have been established for each of six calculated metrics (a subset of the ten metrics used in the SCI).


The metrics incorporated into BioRecon assessments include:

  • Number of total macroinvertebrate species (taxa)
  • Number of long lived taxa, those that require more than one year to complete their life cycle
  • Number of sensitive taxa
  • Number of clinger taxa
  • Number of Ephemeroptera (mayflies) taxa
  • Number of Trichoptera (caddisflies) taxa.


Lake Vegetation Index (LVI)                                     

FDEP SOP: FS 7310 

Aquatic Plants West Jupiter Wetlands

The Lake Vegetation Index (LVI) method involves dividing a lake into 12 units and identifying plants in 4 of the 12 units. Plants are identified in each unit by a visual boat "drive by" and also via a transect approach. A sampling tool is deployed a minimum of five times in transect to look for the presence of submerged aquatic plants. All plants for a unit are recorded in a single column on the Lake Vegetation Index Data Sheet and a dominant or co-dominant is assigned based on aerial extent. Unknown plants are brought back for expert identification and verification. The sampling season for the LVI is May through November. Data generated on the presence of species is used to calculate four biological metrics - each of which has been shown to respond to human disturbance.


The metrics are:

  • Native Taxa
  • Invasive Taxa
  • Sensitive Taxa
  • Dominant Coefficient of Conservatism (C of C).

Aquatic Plant Identification References:


Lake Sampling Procedure- 12 segments


Marine Benthic Sampling                                                    


Sponges and mollusks

The Dredge method involves taking three or more replicate grab samples with a Petite PONAR or Ekman sampler.  The entire sample is sorted and all organisms are identified to the lowest practical taxonomic level. The Shannon-Weiner Diversity Index is calculated for the whole sample.



2 celled organism

The Rapid Periphyton Survey (RPS) quantifies the extent and abundance of algae in a 100 m stream segment. Nine observations are made every 10 m for a total of 99 observations (11 transects, including 0 and 100 m marks). A canopy measurement is made at the mid-point of each transect using a spherical densiometer. A small handful of substrate is randomly collected at each transect point and is visually examined for the presence/absence and for the type of algae (filamentous, diatom, or other). The average thickness is measured perpendicular to the substrate and this noted on the Rapid Periphyton Survey benchsheet. The results of this sampling will allow for the eventual development of expectations for both reference sites and those where the algae may be interfering with the designated use of a waterbody.


Stream Condition Index (SCI)                      


Biologists conducting Biological Assessment

The SCI is a composite macroinvertebrate index for use in flowing streams. Sampling consists of 20 dipnet sweeps of the most productive habitats found in a 100-meter stretch of a stream.  Organisms collected in these sweeps are brought back to the laboratory for processing.  Data generated on the species and abundance of these organisms is used to calculate ten biological metrics - each of which has been shown to respond predictably to human disturbance. 


The metrics are:

  • Number of total taxa
  • Number of long lived taxa, those that require more than one year to complete their lifecycle,
  • Number of Ephemeroptera (mayflies) taxa,
  • Number of Tricoptera (caddisflies) taxa,
  • Number of Florida sensitive taxa
  • Number of clinger taxa
  • Percent dominant taxon
  • Percent Tanytarsini
  • Percent very tolerant taxa,
  • Percent filterers.






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Contact List- Watershed Management and Monitoring


Central District Office

Watershed Management and Monitoring Section

3319 Maguire Blvd, Suite 232

Orlando, Florida 32803-3767

phone: 407-897-4100

fax: 850 412-0472


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Last updated: August 31, 2015

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