7840

• UCREFRP Catalog Number: 7840
• Author: Wolz, E. R. and D. K. Schiozawa
• Title: Soft Sediment Benthic Macroinvertebrate Communities Of The Green River At The Ouray National Wildlife Refuge, Uintah County, Utah
• USFW Year: 1995
• USFW - Doc Type: Great Basin Naturalist
• Copyright Material: YES

216

GREAT BASIN NATURALIST

[Volume 55

TABLE 2. Densities of benthic invertebrates (#/m2) from the Green River, river channel habitat, Ouray National
Wildlife Refuge, Ouray, DT.

15 July 1991 12 August 1991
# of samples # of samples
Taxon Density/m2 (95% C.L,) processed Density/m2 (95% C,L,) processed
Nematoda 24,881 (13,107-47,302) 6 2421 (2063-2840) 5
Oligochaeta 3426 (2565-4570) 18 11,182 (7497-16,678) 5
Insecta
Ceratopogonidae 3608 (2731-4767) 27 13,026 (9316-18,215) 5
Chironomidae 4150 (2798-6155) 5 3516 (2454-5037) 30 .
Early instars 1037 3016
Chironomus 346 0
Cyphomella 0 58
Lenziella 576 0
Paramerina 115 0
Paratendipes 0 96
Polypedilum 1844 269
Procladius 115 ' 0
Psectrocladius 115 0
Stempellinella 0 58
Tanytarsus 0 19

TABLE 3. Densities of benthic invertebrates (#/m2) from the Green River, ephemeral side channel habitat, Ouray
National Wildlife Refuge, Ouray, DT.

3 June 1991 1 July 1991
# of samples # of samples
Taxon Density/m2 (95% C,L,) processed Density/m2 (95% c.L.) processed
Nematoda 261,680 (88,934-769,968) 5 302,603 (215,886-424,154) 5
Oligochaeta 2728 (2096-3546) 15 12,796 (10,681-15,329) 5
Insecta
Ceratopogonidae 0 30 0 5
Chironomidae 2325 (1843-2927) 30 8185 (6385-10,491) 5
Early instars 979 2075
Chironomus 1134 3112
Cryptochironomus 0 115
Cryptotendipes 19 461
Lenziella 96 1383
Polypedilum 19 692
Procladius 0 346
Tanypus 19 0
Tanytarsus 58 0

sediment particles (sands and structural clays)
that remained in the plastic tray were periodi-
cally examined for specimens. If none were
found, the sediments were discarded. Material
collected on the screen was stored in 70%
ETOH.
Samples sorted were randomly chosen from
the 50 samples taken at each site and date. Each
sample was placed in glass petri dishes (from
one to six dishes depending on the amount of
material) and sorted under a dissecting micro-
scope (see Tables 1-4 for number of samples
processed). Four major taxa (Nematoda, Oligo-

.,

chaeta, Ceratopogonidae, and Chironomidae)
were counted. Only Chironomidae were iden-
tified to the generic level. Miscellaneous taxa
were also recorded but were not quantified
(see Table 5).
The number of samples sorted from each site
and sampling date was determined as follows:
5 of the 50 samples were randomly selected
and the four major taxa were counted. Because
of their contagious distribution (determined by
calculating variance to mean ratios), numbers
of individuals of each taxon were then log
transformed (x + 1). The variance and mean