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CONDITION ASSESSMENT FOR THE ESCAMBIA RIVER, FL, WATERSHED: BENTHIC MACROINVERTEBRATE SURVEYS USING A PROBABILISTIC SAMPLING DESIGN (POSTER SESSION)
Citation:
Didonato, G T., T H. Roush, V D. Engle, AND J K. Summers. CONDITION ASSESSMENT FOR THE ESCAMBIA RIVER, FL, WATERSHED: BENTHIC MACROINVERTEBRATE SURVEYS USING A PROBABILISTIC SAMPLING DESIGN (POSTER SESSION). Presented at 2000 Annual Meeting of the American Society for Microbiology, Los Angeles, CA, 21-25 May, 2000.
Description:
Probabilistic sampling has been used to assess the condition of estuarine ecosystems, and the use of this survey design approach was examined for a northwest Florida watershed. Twenty-eight lotic sites within the Escambia River, Florida, watershed were randomly selected and visited during July-August, 1996. Hydrologic and water chemistry were collected, and benthic macroinvertebrates were sampled using Hester-Dendy artificial substrate samplers deployed for 27-29 days. Macroinvertebrates were preserved and identified down to the lowest practical taxonomic level (usually Genus). A total of 3476 benthic invertebrates were identified, comprising 58 taxa and 28 families. The numerical dominants were the midges Tanytarsus and Tribelos (23.7% of the sampled animals) and oligochaetes (26.5%), although oligochaete numbers were strongly influenced by one particular site. Stenonema and Baetis were the most common mayflies and accounted for 7.9 and 1.4% of the total invertebrates, respectively, while caddisflies (genus Hydropsyche) composed 5.8% of the identified fauna. These data were summarized using common metrics, including number of taxa, number of EPT taxa, and the Shannon-Weiner diversity index, to assess stream condition with a Stream Condition
Index (SCI) developed for Florida.