7923

• UCREFRP Catalog Number: 7923
• Author: Carter, J. G. and V. A. Lamarra.
• Title: An Ecosystem Approach To Environmental Management, Chapter 17.
• USFW Year: n.d.
• USFW - Doc Type: 261-287
• Copyright Material: YES

interrelationships between the organisms which process the
coarse particles (called shredders) and the microbial
flora which colonize the particles have been demonstrated
(Cummins, 1973). This processing rate (by structural
components) is a quantifiable behavioral characteristic of
any river system which is dependent upon temperature,
turbulence, pH, water hardness and ionic constituents
(Lush and Hynes, 1973).

The organisms which feed on the FPOM produced are
called collectors. They aggregate the small particles by
their feeding activities. A preliminary analysis of the
macroinvertebrate data collected on the White River
indicates that the dominant types of invertebrates are
collectors dependent upon the heterotrophic food chain
(Figure 9).

FILTER FEEDERS

r~'\

I '\-~ DETRITlVORES
.... I \ !\ ~ATORS
~ \ / ,
. 'A~ I " r\ ..~
~~ HERBIVORES ,'\, '~/
" '\ ~....
\~ I / '~
, ..
..

Figure 9. The distribution (% composition) of the major
functional groups of macroinvertebrates in a riffle habitat
at Southam Canyon in the White River during 1981.

Respiration rates and absence of invertebrates from
decomposing leafpaks indicate microorganisms are very
important in the regeneration of this allochthonous
detritus for nutrients (Figure 8).

The impact of physical-chemical factors on the
distribution of macroinvertebrates is usually indirect,
with the major controlling factor being the quantity or
quality of food. In general, invertebrates are adapted to

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