9615

• UCREFRP Catalog Number: 9615
• Author: Miller, W. J., D. E. Rees and J. A. Ptacek.
• Title: Draft Summary of 2001 Tasks Fryingpan/Roaring Fork Rivers Fishery Study.
• USFW Year: 2001.
• USFW - Doc Type: Fort Collins, CO.
• Copyright Material: NO

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In unpolluted waters diversity values typically range from near 3.0 to 4.0. In polluted waters
this value is generally less than 1.0. The evenness value ranges between 0.0 and 1.0.
Values lower than 0.3 are generally considered indicative of organic pollution (Ward and
Kondratieff 1992).
The Hilsenhoff Family Biotic Index (F.B.I.) is often used in macroinvertebrate studies as a
means of detecting organic enrichment. In this study it may be a useful tool for monitoring
differences between the sites that may not be attributed to discharge. Because the F.B.I.
requires modification for use in many areas, the number indicating a certain water quality
rating will vary among regions. Comparison of the values produced within a given system
should, however, provide information regarding difference in sites based on nutrient
enrichment. Values for the F.B.I. range from 0.0 to 10.0, and increase as water quality
decreases.
The Ephemeroptera, Plecoptera, Trichoptera (E.P.T.) index will be employed to assist in the
analysis of the data It is a direct measure of taxa richness among species that are typically
considered sensitive to pollution or other disturbances. This measurement is simply given as
the total number of distinguishable taxa in the orders Ephemeroptera, Plecoptera and
Trichoptera found at each station. This number will naturally vary among river systems.
Species richness was also reported for each sampling event during the study. This
measurement is simply reported as the total number of species collected on each date from
each sampling location. It is similar to the E.P.T. index, except that it includes all aquatic
macroinvertebrate species. It is useful for describing differences in habitat complexity or
aquatic conditions between rivers or site locations. Species richness also provides some
indication of habitat preference.
Differences in macroinvertebrate production at each site were measured using
macroinvertebrate density and biomass. Macroinvertebrate density was reported as the
mean number of macroinvertebrates per square meter found at each location. Densities
were compared between sites for each sampling occasion. Biomass was another
Draft 2001 Task Summary Report Page 17
Miller Ecological Consultants, Inc. December 18, 2001