Inventory of the Aquatic Resources in the East

190 Pages·1993·4.7 MB·English

by  Boyle, T.P., Hoefs, N..J.

WftP pfrV\kU£< V&QH\ 2-IDM
Inventory of the Aquatic Resources
in the East & North Forks
of the Virgin River in & above
Zion National Park, Utah
Terence P. Boyle
Nancy Hoefs
J.
&
David ft Beeson
November 1993
Applied Research Branch
Water Resources Division
National Park Service

Inventory of the Aquatic Resources
in the East & North Forks
of the Virgin River in & above
Zion National Park, Utah
Terence P. Boyle
Nancy Hoefs
J.
&
David ft Beeson
November 1993
Applied Research Branch
Water Resources Division
National Park Service
Digitized by the Internet Archive
in 2012 with funding from
LYRASIS Members and Sloan Foundation
http://archive.org/details/inventoryofaquatOOboyl
TABLE OF CONTENTS
Introduction
1
Study Area 4
Methods 6
Results and Discussion 11
Physical/Chemical Components 11
BioticComponents 22
Benthic Macroinvertebrate Communities 22
Benthic Habitats 22
Community Structure 23
FunctionalGroupAnalysis 39
Fish 52
SpeciesDistributions 52
Biomass 56
Summary and Conclusions 59
LiteratureCited 63
Appendices 67
Appendix A
Physical/Chemistry Data
Appendix B
Invertebrate Community Data

LIST OF FIGURES
Figure 1. Location of sample sites on the East and North Forks ofthe Virgin River in and above
Zion National Park.
Figure 2. Discharge (m3/sec) measured at sample sites on the East and North Forks.
Figure 3. Hydrography data from 1987 May to October (Water Year 1986) for the East Fork
near Glendale (09404450), the North Fork of the Virgin River near Springdale, Utah
(09406000) and the Virgin River below the confluence of the East and North Forks at
Virgin, Utah (0940550).
Figure 4. Total Nitrogen (mg/l-N) and Total Phosphorus (mg/l-P) concentrations measured
at sample sites on the East and North Forks.
Figure 5. Organic material fractions (VPOM: Very fine particulate organic material, FPOM: Fine
particulate organic material, and CPOM: Coarse particulate organic material) at
sample sites on the East and North Forks.
Figure 6. Taxa richness and density (individuals/sq. meter) of invertebrates sampled at
EF 192 for each sample period.
Figure 7. Taxa richness and density (individuals/sq. meter) of invertebrates sampled at EF 187
for each sample periods. Communities collected in "fine" benthic habitat, are
indicated by black bars, communities collected in "coarse" habitat are indicated by
hatched bars (see text for definition of habitats).
Figure 8. Taxa richness and density (individuals/sq. meter) of invertebrates sampled at EF 176
for each sample periods. Communities collected in "fine" benthic habitat, are indicated
by black bars, communities collected in "coarse" habitat are indicated by hatched bars
(see text for definition of habitats). No invertebrates were found in August 6 samples.
Figure 9. Taxa richness and density (individuals/sq. meter) of invertebrates sampled at EF 161
for each sample periods. Communities collected in "fine" benthic habitat, are indicated
by black bars, communities collected in "coarse" habitat are indicated by
hatched bars (see text for definition of habitats).
Figure 10. Taxa richness and density (individuals/sq. meter) of invertebrates sampled at EF 157
for each sample periods. Communities collected in "fine" benthic habitat, are indicated
by black bars, communities collected in "coarse" habitat are indicated by
hatched bars (see text for definition of habitats). No invertebrates were found in August
7 samples.
Figure 11. Taxa richness and density (individuals/sq. meter) of invertebrates sampled at NF 34
for each sample periods.

Figure 12. Taxa richness and density (individuals/sq. meter) of invertebrates sampled at NF 30
for each sample periods. Communities collected in "fine" benthic habitat, are indicated
by black bars, communities collected in "coarse" habitat are indicated by hatched bars
(see text for definition of habitats).
Figure 13. Taxa richness and density (individuals/sq. meter) of invertebrates sampled at NF 27
for each sample periods. Communities collected in "fine" benthic habitat, are indicated
by black bars, communities collected in "coarse" habitat are indicated by hatched bars
(see text for definition of habitats). No invertebrates were found in August 24 samples.
Figure 14. Taxa richness and density (individuals/sq. meter) of invertebrates sampled at NF 14
for each sample periods. Communities collected in "coarse" habitat are
indicated by hatched bars (see text for definition of habitat).
Figure 15. Taxa richness and density (individuals/sq. meter) of invertebrates sampled at NF 12
for each sample periods. Communities collected in "fine" benthic habitat, are indicated
by black bars, communities collected in "coarse" habitat are indicated by
hatched bars. Dotted bars indicate the predominant habitat type found after
deposition of sand material (see text for definition of habitats).
Figure 16. Functional feeding group analysis of benthic invertebrates before and after summer
rainfall runoff events (Mid-July) at EF192 in the predominant benthic habitat.
Figure 17. Functional feeding group analysis of benthic invertebrates collected from the
predominant benthic habitats before and after summer rainfall runoff events (Mid-July)
at EF187. (see text for description of benthic habitats).
Figure 18. Functional feeding group analysis of benthic invertebrates collected from the
predominant benthic habitat types before and after summer rainfall runoff events
(Mid-July) at EF176. The cobble/boulder habitat after mid-July was not analyzed,
(see text for description of benthic habitats).
Figure 19. Functional feeding group analysis of benthic invertebrates collected from fine and
coarse benthic habitat types before and after summer rainfall runoff events (Mid-July)
at EF161. (see text for description of benthic habitats).
Figure 20. Functional feeding group analysis of benthic invertebrates collected from fine and
coarse benthic habitat types before and after summer rainfall runoff events (Mid-July)
at EF157. (see text for description of benthic habitats).
Figure 21. Functional feeding group analysis of benthic invertebrates before and after summer
rainfall runoff events (Mid-July) at NF30 from the predominant benthic habitat.
Figure 22. Functional feeding group analysis of benthic invertebrates collected from the
predominant benthic habitats before and after summer rainfall runoff events (Mid-July)
at NF30. (see text for description of benthic habitats).
iii