Invasive Plant Distribution in the Luckiamute
River Basin, Central Oregon Coast Range:
Preliminary Analysis of Geomorphic and LandUse Variables
Steve Taylor, Earth and Physical Sciences, Western Oregon University
Bryan Dutton, Biology Dept., Western Oregon University
ALTERNATIVE PLOT LINE:
What happens when you lock a biologist, a
geologist and a bunch of college students
in a science building for five years?
Steve Taylor, Earth and Physical Sciences, Western Oregon University
Bryan Dutton, Biology Dept., Western Oregon University
• Introduction
• Physiographic Setting
• Plant Survey Methodology
• Results
• Conclusion
INTRODUCTION
• Invasive plants are a pervasive problem in the U.S.
 Disrupt habitats and displace native species
 Annual losses in U.S. ~$130,000,000 (Pimentel et al., 2000)
• Primary dispersal pathways:
 Anthropogenic disturbance
 Enhancement by geomorphic transport processes
(wind, water, gravity, animal; Merritt and Wohl, 2006)
• Understanding the controls on spatial distribution of
invasive plants is critical for development of
watershed restoration and management programs.
Research Objectives
(1)To identify spatial associations and invasive plant
distributions in riparian zones of Western Oregon.
(2) To consider controlling variables and develop
predictive models for use in watershed restoration.
Study area: Luckiamute River Basin, Western Oregon
• Local outdoor laboratory close to Western Oregon University.
• Ad = 815 km2; variable geology, geomorphology, land-use.
• Land-use / cultural history typical of mid-Willamette Valley.
• Biotic and abiotic variables are well-suited for study of
causal factors controlling spatial distribution of invasives.
PHYSIOGRAPHIC SETTING OF THE
LUCKIAMUTE WATERSHED
Arc
de
Casca
Cascadia
Klamath
Mountains
0
Volcanic
Willamett
e L
owlan
d
Range
Luckiamute
Study Area
Coast
Subduction
Zone
PHYSIOGRAPHIC MAP OF WESTERN OREGON
75 km
From Luckiamute Watershed Council
Plant survey locations
Base from Luckiamute Watershed Council
Luckiamute River at Helmick State Park
Bankfull Stage 3/27/05 3800 cfs
Ty
Tsr
Ty
III
Ty
Ty
Ty
Ty
Ty
Ty
Qal
IV
II
Ty
I
Ty
Tss
Ty
Tss
Tt
Qal
Tss
Tss
Tt
Qal
Tss
Tt
Qal
Fault
Hal
Tsr
aul
Tsr
Co
rv
Tsr
all
is
Fa
ult
yF
a l le
sV
Kin
g
Hal Holocene alluvium
Qal Quaternary alluvium
Oligocene intrusive
Ty Yamhill Formation
Tss Spencer Formation
Tt Tyee Formation
Tsr Siletz River Volcanics
t
Tt
0
N
5 km
Willamette Valley
Yamhill-Intrusive Domain
Spencer-Valley Fill Domain
Ts
el 470 ft
Max Missoula Flood El. = 400 ft)
el 220 ft
Qtm (Bela, 1981)
Qff2 (O’Connor et al., 2001)
Willamette Silt
Plant Survey Methodology
Objective: To determine extent and distribution of
all vascular plant species in riparian zone.
Site Selection Criteria:
• Uncultivated wooded riparian areas along the Luckiamute
and related tributaries.
• 100-m buffer of vegetated, ± non-cultivated land transverse
to the Luckiamute River or one of its tributaries.
• Utilized 2001-vintage DOQs to delineate uncultivated areas
in riparian zone buffer.
• Identified riparian landowners from county tax records
and contacted for permission to access.
Rickreall Ck
5
9
12
Li
tt
Fa
nn
Western
Western Oregon
University
Oregon
University
le
Lu
o
Ri
dg
19
ck
ia
m
e
ut
e
2
18
16
Lu
ck
ia
m
Helmick
State
Park
20 13
4 3
6
10 7
17
15 1
r
ve
i
R
ut
e
8
So
ap
Ck
11
14
Survey Transect Locations
Watershed Boundary
0
5 km
lla
m
ve
r
Wi
Ri
ya R
iv e r
p oo
s
C a la
ar
y
ett
e
M
Ri v
er
N
Data Collection Procedures
Equipment
• Tape measure
• One square meter frame; 1 x 100 m quadrats
Methods
• Conducted transect surveys perpendicular to
channel reach
• All vascular plants identified in each square
meter along the transect
• Data recorded as percent cover
• GPS positions and light-meter data collected
• Field data entered into spreadsheets,
validated, GIS compiled
RESULTS
PLANT SURVEY TRANSECT SUMMARY
Total No. of Transects
Length of Transects
Width of Transects
Average Area per Transect
Cumulative Survey Area
Average Transect Spacing
20
29-100 m
1m
89 m2
1785 m2
5.1 km
OVERSTORY – RIPARIAN FOREST CANOPY
COMMON NAME
SCIENTIFIC NAME
Oregon ash
Big leaf maple
Western hazel
Creek dogwood
Douglas fir
Willow
Vine Maple
Red Alder
Oregon white oak
(Fraxinus latifolia)
(Acer macrophyllum)
(Corylus cornuta subsp. Californica)
(Cornus sericea)
(Pseudostuga menziesii)
(Salix sp.)
(Acer circinatum)
(Alnus rubra)
(Quercus garryana)
PERCENT OF
TRANSECTS
60%
55%
30%
25%
25%
20 %
15%
15%
15%
RIPARIAN UNDERSTORY
Total No. of Species Encountered:
Total No. of Invasive Species:
Total No. of Native Species:
Total No. of Genus/Family-Level ID
Ratio No. Natives / No. Invasives
Total Area Invasives (m2)
Total Area Natives (m2)
Total Area Genus/Family Level (m2)
Total Area No Cover (m2)
Ratio Area Natives / Area Invasives
170
55
75
40
1.4
228
477
78
1002
2:1
12.8%
26.7%
4.4%
56.1%
VASCULAR PLANTS NATIVE SPECIES
VASCULAR PLANTS INVASIVE SPECIES
The “Big 3” Invasives
Reed canarygrass
(Phalaris arundinacea)
Himalaya blackberry
(Rubus armeniacus)
Japanese knotweed
(Polygonum cuspidatum)
Rickreall Ck
5
9
Li
tt
Fa
nn
Western Oregon
University
12
le
Lu
o
Ri
dg
19
ck
ia
m
e
ut
Western Oregon
University
e
20 13
2
18
16
Lu
4 3
6
10 7
ck
ia
m
17
15 1
r
ve
i
R
ut
e
8
So
ap
Ck
11
14
Survey Transect Locations
Watershed Boundary
0
5 km
lla
m
ve
r
Wi
Ri
ya R
iv e r
p oo
s
C a la
ar
y
ett
e
M
Ri v
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N
SUMMARY OF RESULTS FROM SPATIAL
DISTRIBUTION ANALYSIS
• The areal distribution of native to invasive plants is 2:1.
• Himalayan blackberry, Reed canary grass and Japanese knotweed
are the most widespread invasive species by area cover.
• Himalayan blackberry and Reed canary grass are ubiquitously
distributed throughout the drainage network and across floodplain
regions.
• Japanese knotweed is more restricted in occurrence to upper
reaches of the drainage network and to narrow zones (<30 m)
adjacent to the active channel.
• Plant species richness decreases with increasing invasive coverage.
CONCLUSION
Results from this study provide:
• Important baseline data on the distribution of vascular
plant species in western Oregon.
• A framework for discerning patterns of plant invasion in
the Luckiamute watershed.
• The foundation for developing invasive plant dispersal
and distribution models.
Preliminary implications for restoration:
• Riparian canopy shading increases species richness and
decreases occurrence of invasive mono-cultures .
• Plant trees and maintain wide forest buffer in riparian zone.
ACKNOWLEDGEMENTS
• The Katherine Bisbee II Fund of the Oregon
Community Foundation
• Western Oregon University Faculty
Development Fund
• Student Research Assistants:
Daniel Asakawa, Catherine Drury, Moriah
LaChappel-Schalock, Ian Macnab, Katherine Noll,
Rachel Pirot, Benjamin Purkerson, Ryan Stanley,
Alicia Thompson, Thomas VanNice, Shannon
Wineland
• Luckiamute property owners