9410

• UCREFRP Catalog Number: 9410
• Author: Wydoski, R. S. and E. J. Wick.
• Title: Ecological Value of Floodplain Habitats to Razorback Suckers in the Upper Colorado River Basin.
• USFW Year: 1998.
• USFW - Doc Type: Denver.
• Copyright Material: NO

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Table 1. Range of the mean number of zooplankton (cladocerans and copepods)
from investigations of various habitats in the Upper Colorado River
Basin.11
Habitat Ranqe of the mean number of orqanisms/liter

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Main Channel ~/

o

1.3

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Backwaters

o

13.1

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Floodplain Habitats

4.2

81.5

~/ The mean number of zooplankton were obtained from the following studies:
Grabowski and Hiebert (1989) i Cooper and Severn (1994a), b, c, d, and ei
Mabey and Schiozawa (1995). The number of samples taken, sampling gear
used, seasons (late spring and summer) and years of sampling differed
so ranges are used to illustrate the relative productivity of
zooplankton.

~/ Most (4) of the investigations were made on the Green River. However the
data include two investigations on the Colorado River and one
investigation on the Gunnison River, a major tributary of the Colorado.

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Table 2. Mean number of zooplankton (cladocerans and copepods) from various
habitats in or along the Green River, Upper Colorado River Basin,
illustratinq seasonal differences. 11
Habitat Month/Year Range of the mean number
of oroanisms/liter

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Main Channel 7/91 1.3
8/91 0.3
Backwater (Large) 6/91 63.4
Backwater (Small) 7/91 7.1
8/91 1.5
Floodplain Habitat ~/ 6/91 205.9
7/91 311.4
8/91 690.2

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~/ Data summarized from Mabey and Schiozawa (1995).

~/ This habitat is a 147 hectare depression wetland that fills during high
streamflows and retains water by a dike and water control structure at the
former natural outlet.

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More detail of the mean numbers of zooplankton in different habitats of
the Upper Basin are summarized in Appendices 1 and 2. Grabowski and
Hiebert (1989) reported 0.2 to 0.136 cladocerans and copepods per liter in
the middle Green River main channel and 0.02 to 0.289 in backwaters during

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