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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Other Fish Habitat Elements
The final study objective is the determination of the relationship between flow levels and
other fish habitat elements. The other fish habitat elements include macroinvertebrate
populations, water quality parameters and spawning habitat. In 2001 we made spring and
fall macroinvertebrate collections, installed thermographs and began fall spawning
habitat studies.
Benthic Macroinvertebrate Collection Sorting and Identification
Analysis of macroinvertebrate samples has become a widely accepted tool used to
monitor aquatic conditions in lotic environments (Plaflcin et al. 1989). Macroinvertebrate
community structure and function is a product of the physical and biological influences
present in the environment. The dominant force contributing to the structure of aquatic
macroinvertebrate communities is dependent upon the time of year, adaptations of the
given macroinvertebrates, and magnitude of disturbances (Poff and Ward 1989). The
flow regime of a stream is usually considered to be one of the most important factors that
influence aquatic communities (Poff et al. 1997).
Flow is particularly important because it is often correlated with numerous other factors
that influence the aquatic community (Cushman 1985; Poff and Ward 1990). These
factors include: depth, velocity, thermal changes, renewal of resources, etc. The
macroinvertebrate community composition of a given stream is adapted to, and
dependent on, the flow regime (as well as other variables) that exist in that stream.
Releases from the impoundment at Ruedi Reservoir directly influence the
macroinvertebrate and fish communities that exist downstream. In many ways, the
impoundment and physical features associated with the discharge are responsible for the
exceptional trout fishery that exists downstream. The influence of discharge on the
macroinvertebrate community can be ascertained by quantitatively sampling strategic
reaches of the Fryingpan and Roaring Fork rivers before, during and after target flows.
Draft 2001 Task Summary Report Page 15
Miller Ecological Consultants, Inc. December 18, 2001