Influence of Geomorphology and Land Use on Distribution and Abundance of Salmonids in a ...

225 Pages·2013·8.51 MB·English

by  Schwartz, John Steven

AN ABSTRACT OF THE THESIS OF
John Steven Schwartz for the degree of Master of Science in Fisheries Science
presented on November 20. 1990.
Title: Influence of Geomorpholoay and Land Use on Distribution and
Abundance of Salmonids in a Coastal Oregon Basin
Redacted for privacy
Abstract approved:
%t\Inley V. Gregor
The basin morphology of a fifth-order coastal Oregon stream was
analyzed across a hierarchy of spatial scales which included segments,
reaches, and channel units. These scales represent valley and channel
characteristics based on functional processes of geomorphology and attempt
to organize heterogeneity of stream habitat within a drainage network. Four
segments were associated with major geologic influences on the landscape,
and boundaries were selected by basin patterns of the valley corridor observed
by indices of valley floor width. Segments provided a template for reach
characteristics. Narrow valley segments had greater reach lengths of multiple
channels, and densities of boulders than wide valley segments. Within wide
valleys of alluvium, incision of the channel occurred in three reaches and had
reduced multiple channel lengths and bedforms composed of bedrock. Reach
boundaries were selected by major shifts in active channel width and condition
of geomorphic surfaces along basin longitudinal profiles, and these boundaries
coincided with changes in bedform gradient. Reach composition of channel
unit types was associated with gradient; percent length of pools and glides was
inversely related to gradient.
Basin patterns of salmonid distribution and abundance were examined at
the different hierarchical scales. Juvenile chinook and coho salmon exhibited
strong basin gradients of abundance within a upstream-downstream
continuum. Juvenile chinook dominate the lower basin and juvenile coho
dominate the upper basin, and the transition in abundances occurred between
the two mid basin segments. From a basin perspective of reaches, salmonid
abundances were not related to any specific valley landform. Abundances of
trout (ages 0+ and 1 +) were directly related to mainstem reach gradient. Trout
occupied fast-water channel units among the mainstem reaches, while juvenile
salmon were more variable in use of channel unit types. Salmonid densities per
channel unit were 2 to 8 times greater in the tributary reaches than the
mainstem reaches. In the tributaries, pools and glides were used extensively
for habitat.
Salmonid abundances in the tributaries were associated with stream size
and gradient. Densities of juvenile coho were greater in low-gradient tributaries,
and densities of cutthroat trout (age 1 +) and trout fry (age 0+) were greater in
high-gradient and larger tributaries. Juvenile coho occupied streams with
gradients less than 4%. In the tributaries, composition of channel unit types
was important because salmonids used mostly pools and glide habitats, and
percent length of pools and glides was associated with stream gradient.
Timber harvest in first- to third-order tributaries detrimentally affected
cutthroat trout, where areal densities of trout were significantly lower in clearcut
sites without buffers than in patch-cut sites with buffers and unharvested sites.
Analysis of land-use effects on salmonid populations accounted for site
differences in geomorphology. Tributaries contained both allopatric cutthroat
trout populations and cutthroat trout populations sympatric with juvenile coho
salmon. Sympatric sites exhibited greater significant differences in trout
densities among land-use treatments than all sites combined, and allopatric
sites were not different among treatments. CWD volumes significantly were
lower in clearcut sites (1.6 m3/100 m2) than unharvested sites (2.9 m3/100 m2).
Reexamining the Alsea Watershed Study (AWS) streams 23 years after logging
demonstrated that detrimental effects were long term. In Needle Branch (the
AWS clearcut watershed), older age classes of trout were substantially reduced
in numbers after logging. Competitive interactions between juvenile coho
salmon and cutthroat trout with a loss of CWD cover may contribute to the long-
term decline in cutthroat trout abundance after logging.
Influence of Geomorphology and Land Use on
Distribution and Abundance of Salmonids
in a Coastal Oregon Basin
by
John Steven Schwartz
A THESIS
submitted to
Oregon State University
in partial fulfillment of
the requirements for the
degree of
Master of Science
Completed November 20, 1990
Commencement June 1991
APPROVED:
Redacted for privacy
Associate ProfessorfFisheries in charge majc(r,
Redacted for privacy
Head of Department of Fisheries and Wildlife
Redacted for privacy
Dean of G a te School
Date thesis is presented November 20, 1990
Typed by researcher for John Steven Schwartz
ACKNOWLEDGEMENTS
I would like to thank my major professor Dr. Stan Gregory for his
guidance and many hours of work he contributed during all stages of this
project. Thanks are due to Dr. Bob Beschta, Dr. James Hall, and Dr. David
Hann for serving on my graduate committee. Dr. Bob Beschta provided much
energy during the initial stages of the project design and can't be thanked
enough for getting the "ball rolling". Dr. James Hall furnished me with many
references, his office was more reliable than Kerr Library. For preparation of
Chapter II, I appreciate suggestions from Dr. Gordie Reeves and Dr. James Hall
(who reviewed an early version of the manuscript), and Dr. Gordon Grant and
Dr. Fred Swanson.
Funding was provided by Coastal Oregon Productivity Enhancement
(COPE) project. Basin surveys were done with the aid of the U.S. Forest
Service, PNW Forest Research Laboratory, Anadromous Fish Group (USFS),
OSU Stream Team, and Adaptive COPE in Newport, Oregon. A project of this
size could not have been accomplished without the help of many people.
I
would like to give my thanks to a few: Dr. Gordie Reeves (USFS), Dave Price
(USFS), Randy Wildman (OSU), Linda Ashkenas (OSU), and Dr. Tom McMahon
(COPE); special thanks must be given to Kelly Burnett (USFS) for an
exceptional job of organizing field crews and managing data.
During the first summer of tributary field surveys, Curt Veldhuisen and I
worked together, at times through difficult terrain (crawling through 10-year-old
Douglas-fir plantations to get to the stream). Many thanks to Curt who blazed
the trail.
Finally, I would like to thank Vicki Ursitti, my friend, my companion, for
her encouragement and confidence in me, that yes someday I would finish.
TABLE OF CONTENTS
Page
CHAPTER I:
GENERAL INTRODUCTION
1
Study Area 3
General Basin Distribution of Salmonids 6
CHAPTER II:
GEOMORPHOLOGY OF THE DRIFT CREEK BASIN, AND DISTRIBUTION
AND ABUNDANCE OF SALMONIDS: A BASIN PERSPECTIVE
INTRODUCTION 8
METHODS 17
Geomorphic Analysis 19
Segments 19
Reaches 20
Channel Units 22
Salmonid Distribution and Abundance 24
Salmonid Abundance by Hierarchical Scales 25
Habitat Electivity at Channel Units 25
Salmonid Abundance at Tributary Junctions 25
RESULTS 26
Geomorphic Analysis 26
Segments 26
Reaches 32
Channel Units 44
Salmonid Distribution and Abundance 47
Basin 47
Segments 54
Reaches 56
Tributary Junctions 60
Channel Units 60
DISCUSSION 73
Geomorphology 73
Salmonid Distribution and Abundance 79
CHAPTER III:
LAND-USE INFLUENCES ON STREAM HABITAT AND
SALMONID ABUNDANCE IN THE DRIFT CREEK TRIBUTARIES 85
INTRODUCTION 85
METHODS 91
Study Design 91
Basin Analysis 91
TABLE OF CONTENTS (continued)
Page
Stream Habitat Measurements 95
Channel Unit Characteristics 95
Substrate and Spawning Gravels 96
Coarse Woody Debris 96
Salmonid Abundance Estimates 96
Habitat Use by Salmonids 97
Statistical Analysis 98
RESULTS 100
Physical Stream Habitat and Land-Use Effects 100
Channel Unit Composition 100
Widths and Depths 100
Substrate and Spawning Gravel 106
Coarse Woody Debris 107
Salmonid Abundance 109
Relationships With Physical Habitat 109
Habitat Use of Channel Units 114
Land-Use Effects 114
DISCUSSION 123
CHAPTER IV:
AN ALSEA WATERSHED STUDY COMPARISON: A TEMPORAL
PERSPECTIVE IN THE DRIFT CREEK BASIN ON THE EFFECTS
OF LAND USE 129
INTRODUCTION 129
An Overview of the Alsea Watershed Study 129
The Alsea Watershed Study Comparison 132
METHODS 134
Stream Habitat Measurements 134
Alsea Watershed Study 134
The 1988-1989 Study Design 134
Salmonid Population and Biomass Estimates 135
Alsea Watershed Study 135
The 1988-1989 Study Design 135
RESULTS 140
Stream Habitat Measurements 140
Salmonid Population and Biomass Estimates 140
DISCUSSION 149
CHAPTER V: SUMMARY 160
LITERATURE CITED 164
APPENDIX 174
LIST OF FIGURES
Figure Page
1. Location of the Drift Creek basin in Oregon; and map
showing stream order. 4
2. General distribution of summer-rearing juvenile salmon in
the Drift Creek basin. 7
3. Hierarchical scales of basin morphology. 15
4. Drift Creek basin map showing extent of 1988 and 1989
surveys and reach designations. 18
5. Longitudinal profile of valley floor width indices (VFW!)
along Drift Creek. Field surveys start at 6.53 km upstream
from the confluence of Lyndon Creek. 27
6. Geologic map of Drift Creek basin (based on map by
Snavely et al. 1976). 28
7. Longitudinal stream profile of Drift Creek; arrows indicate
major slope breaks. 30
8. Longitudinal profile of Hack stream-gradient indices along
Drift Creek. 31
9. Longitudinal profile of stream power indices along Drift Creek. 31
10. Longitudinal profile of active channel widths along Drift Creek.
Solid arrows indicate locations of hillslope-constrained sub-
reaches, and open arrows indicate locations of incised
reaches. 38
11. Percent composition of slow-water channel units versus reach
gradient for Drift Creek reaches. 45
12. Percent composition of channel unit types for Drift Creek
reaches. 46
13. Longitudinal profiles of abundance of juvenile chinook salmon
by (A) numbers per channel unit, (B) linear densities per
channel unit, and (C) areal densities per channel unit.
Lines indicate range of maximum abundances. 48
14. Longitudinal profiles of abundance of juvenile coho salmon
by (A) numbers per channel unit, (B) linear densities per
channel unit, and (C) areal densities per channel unit.
Lines indicate range of maximum abundances. 49
LIST OF FIGURES (continued)
Figure Page
15. Longitudinal profiles of abundance of trout fry (age 0+)
by (A) numbers per channel unit, (B) linear densities per
channel unit, and (C) areal densities per channel unit.
Lines indicate range of maximum abundances. 50
16. Longitudinal profiles of abundance of steelhead trout (age 1 +)
by (A) numbers per channel unit, (B) linear densities per
channel unit, and (C) areal densities per channel unit.
Lines indicate range of maximum abundances. 51
17. Longitudinal profiles of abundance of cutthroat trout (age 1 +)
by (A) numbers per channel unit, (B) linear densities per
channel unit, and (C) areal densities per channel unit.
Lines indicate range of maximum abundances. 52
18. Basin transition in abundances (fish numbers per channel
unit) of juvenile chinook and coho salmon. 53
19. Segment estimates of salmonid abundances in Drift Creek
for 1988 and 1989. 55
20. Segment and reach estimates of total salmonid abundance
in Drift Creek for 1989. 57
21. Reach estimates of salmonid abundances in Drift Creek for
1989. 58
22. Summary of channel unit use by salmonids in Drift Creek as
percent of total numbers per channel unit type (1989 survey). 62
23. Average numbers of juvenile chinook salmon by channel unit
type for the Drift Creek reaches (1989 survey). 63
24. Average numbers of juvenile coho salmon by channel unit
type for the Drift Creek reaches (1989 survey). 64
25. Average numbers of trout fry (age 0+) by channel unit
type for the Drift Creek reaches (1989 survey). 65
26. Average numbers of trout (age 1+) by channel unit type
for the Drift Creek reaches (1989 survey). 66
27. Location map showing Drift Creek tributary sites by land-use
treatment and year surveyed. 92
28. Composition of channel unit types in Drift Creek tributary
sites by land-use treatment; sites are ordered by increasing
gradient within treatment groups. 101