9505

• UCREFRP Catalog Number: 9505
• Author: Cooper, D. J. and C. Severn.
• Title: Wetlands of the Escalante State Wildlife Area on the Gunnison River, Near Delta, Colorado
• USFW Year: 1994.
• USFW - Doc Type: Hydrology, Water Chemistry, Vegetation, Invertebrate Communities, and Restoration Potential.
• Copyright Material: NO

Invertebrate Spatial Distribution
At all stations water column and benthic samples were
collected to quantify invertebrate densities in each strata.
Benthic invertebrates comprised the greatest percentage of
invertebrates present in all communities (Figure 20). In the
river community 99.7 percent of all invertebrates collected were
benthic. Water column invertebrates had their greatest
contribution in the open water community with 27 percent. At
this study site it is apparent that the benthos provides the
greatest number of invertebrates .that might be available to fish.
Mean water column invertebrates densities L'1 were highest
in the open water followed by the backwater, bulrush, and river
communities (Figure 21). The river community was nearly devoid
of water column invertebrates. Benthic invertebrate densities
were highest in the bulrush followed by the open water, backwater
and river communities. Palustrine wetland communities produced
greater densities of benthic organisms than did the backwater and
river communities. Water column invertebrates were mixed
however, with the palustrine open water communities having the
greatest densities followed by the backwater community. We again
see that benthos are important with regards to overall biomass
production in all communities at this site.
Cladocera were the most abundant water column invertebrates
in the bulrush, backwater and river (not apparent due to scale)
communities while Copepoda were most abundant in the open water
community (Figure 22). Chironomids had greatest densities in the
bulrush and open water communities, greatly exceeding the
backwater and river communities. Insects other than Chironomids
were found in greatest densities in the bulrush community. The
open water and backwater communities had comparable numbers of
insects but at densities less than half of what is present in the
bulrush community. Other invertebrates (i.e. Gastropods,
Nematoda, Cnidaria, and Protozoa) were found only in water column
samples from the bulrush community and were not present in the
other communities. Other invertebrates in the backwater
communities approach densities seen in the palustrine wetland
communities.
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