9457

• UCREFRP Catalog Number: 9457
• Author: Ptacek, J. A., D. E. Rees and W. J. Miller.
• Title: A Study of the Ecological Processes on the Fryingpan and Roaring Fork Rivers Related to Operation of Ruedi Reservoir.
• USFW Year: 2003.
• USFW - Doc Type: Fort Collins.
• Copyright Material: NO

Benthic macroinvertebrates were preserved in ethanol and transported to the lab where they
were sorted, enumerated and identified to the lowest practical taxonomic level (Merritt and
Cummins 1996; Ward et al. 2002). Identification to the "lowest practical taxonomic level"
means that all specimens were identified down to the level that is permitted by the available
morphological characteristics. Early life stages of many species sometimes lack certain
anatomical characteristics that allow the specimen to be identified to the genus or species
level. In these cases the "lowest practical taxonomic level" may mean only the family level;
however, if the available characteristics are consistent with a species that has been
previously confirmed during this study then the individual may be included as a member of
that taxa. In these cases the species name is provided in parentheses.
As a means of quality assurance, qualified personnel inspected each sample after sorting and
a minimum of 20% of all identified taxa were reviewed. Dr. Boris Kondratieff (Professor of
Entomology at Colorado State University) confirmed identifications in all cases where the
identification of a specimen was difficult or questionable.
In instances where proper identification was possible, the Orders Ephemeroptera,
Plecoptera, and Trichoptera were identified to genus (and many down to the species level).
Most specimens of other Orders, including Diptera, were identified to the genus level;
however, members of the family Chironomidae were only identified to subfamily or tribe.
Data collected were used in various indices recommended by the Rapid Bioassessment
Protocols (Plafkin et al. 1989) to provide information regarding macroinvertebrate
community structure, function, and general aquatic conditions. Population densities and
species lists were developed for each sampling site.
Indices used included Shannon-Weaver diversity (diversity) and evenness (evenness),
Hilsenhoff Family Biotic Index (FBI), Ephemeroptera Plecoptera Trichoptera index (EPT),
taxa richness (richness), and description of functional feeding groups.
Benthic macroinvertebrate production at each site was estimated by measuring
macroinvertebrate density and biomass. Density was reported as the mean number of
macroinvertebrates/m2 found at each location. Densities were compared among sites for
Draft Final Report, Fryingpan and Roaring Fork Rivers February 12, 2003
Miller Ecological Consultants, Inc. Page 18