eastern gray squirrel ecology and interactions with western gray squirrels aaron johnston ∙ school...
Post on 23-Jan-2016
218 views
TRANSCRIPT
![Page 1: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/1.jpg)
Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels
Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels
Aaron Johnston School of Forest Resources ∙ ∙University of Washington
Aaron Johnston School of Forest Resources ∙ ∙University of Washington
Photo: Rod GilbertPhoto: Mary Linders
![Page 2: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/2.jpg)
![Page 3: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/3.jpg)
![Page 4: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/4.jpg)
![Page 5: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/5.jpg)
![Page 6: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/6.jpg)
Eastern Gray Squirrel
Photo: Mary Linders
Verts and Carraway (1998)
![Page 7: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/7.jpg)
Eastern Gray Squirrel Introductions
![Page 8: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/8.jpg)
Western Gray Squirrel
Photo: Rod Gilbert
Verts and Carraway 1998
![Page 9: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/9.jpg)
Current Distribution of Western Gray Squirrels
Linders and Stinson (2007)
KLICKITAT COUNTY
PUGET TROUGH
NORTH CASCADES
![Page 10: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/10.jpg)
![Page 11: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/11.jpg)
Objective: Investigate competition
• Are they competing? – Test for competitive effects
• How are they competing?– Describe and compare
components of the niche
![Page 12: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/12.jpg)
Niche
Diet
Shelter
Habitat Behavior
Use of time
Use of space
![Page 13: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/13.jpg)
Niche
ENVIRONMENTAL GRADIENT
AB
UN
DA
NC
E
![Page 14: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/14.jpg)
Resource Partitioning
ENVIRONMENTAL GRADIENT
AB
UN
DA
NC
E
![Page 15: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/15.jpg)
Competitive Exclusion Principle
ENVIRONMENTAL GRADIENT
AB
UN
DA
NC
E
![Page 16: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/16.jpg)
Photo: David J. Slater
InterferenceExploitation
Competition
![Page 17: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/17.jpg)
Patch 1Patch 2
Patch 3
Ideal Free Distribution
![Page 18: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/18.jpg)
Patch 1Patch 2
Patch 3
Equilibrium
![Page 19: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/19.jpg)
Density Dependent Habitat Selection
DENSITY
HA
BIT
AT
QU
ALI
TY
![Page 20: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/20.jpg)
Photo: Danielle Reese
Methods
![Page 21: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/21.jpg)
![Page 22: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/22.jpg)
Utilization Distributions
![Page 23: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/23.jpg)
Measuring Spatial Overlap
![Page 24: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/24.jpg)
0.5 Km
![Page 25: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/25.jpg)
EASTERN WESTERN
0
10
20
30
40A
RE
A (
Ha
)
FEMALE GRAY SQUIRREL HOMERANGES
t15 = 5.36, P = 0.0001
![Page 26: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/26.jpg)
EASTERN WESTERN E/W W/E
-5
0
5
10
% O
VE
RL
AP
FEMALE-FEMALE SPATIAL OVERLAP
F3,30 = 2.89, P = 0.052
Utilization Distributions
![Page 27: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/27.jpg)
0.5 Km
![Page 28: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/28.jpg)
1 Km
![Page 29: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/29.jpg)
Eastern Western
DIS
TAN
CE T
O W
ETLA
ND
(m)
Distance to Wetland
P < 0.001, df = 33
![Page 30: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/30.jpg)
Shrub Cover
WesternEastern
% S
hrub
Cov
er
P = 0.007, df = 33
Shrub Height
Shru
b H
eigh
t (m
)
Eastern Western
P < 0.001, df = 33
![Page 31: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/31.jpg)
Western Gray Squirrel Habitat
Eastern Gray Squirrel Habitat
ENVIRONMENTAL GRADIENT
AB
UN
DA
NC
EEastern Western
![Page 32: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/32.jpg)
H0: There is no difference between eastern and western gray squirrels in their selection of habitat.
GIS Layers
Habitat Plots
Nest Plots
Habitat Analysis
![Page 33: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/33.jpg)
Methods: Habitat measurements
Habitat Plot
OVERSTORY
COMPOSITION STRUCTUREDIVERSITY
UNDERSTORY
![Page 34: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/34.jpg)
F7,152 = 8.6, P < 0.001
ebh enh enl ebl wnl wbh wbl wnh2.64 2.58 1.97 1.77 1.25 1.13 1.04 0.98
Total Understory
ebh ebl enh enl wbh wbl wnh wnl
01
23
4
![Page 35: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/35.jpg)
Methods: Removal Experiment
• Randomized block design– Site = Experimental unit– Removal treatment
assigned randomly to a set of sites in 2009 and another set in 2010
![Page 36: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/36.jpg)
1 Km
Eastern gray squirrel Western gray squirrel
Wetland
Trap
![Page 37: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/37.jpg)
BEFORE AFTER
-0.1
0.4
0.9
1.4
% O
VE
RL
AP
OVERLAP BEFORE AND AFTER EASTERN GRAY SQUIRREL REMOVAL
t16 = 0.133, P = 0.896
![Page 38: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/38.jpg)
Hmmm…
![Page 39: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/39.jpg)
SummarySummary
• Territorial behavior and possible interspecies avoidance
• Differential habitat selection
• More to come on resource use and removal effects
• Territorial behavior and possible interspecies avoidance
• Differential habitat selection
• More to come on resource use and removal effects
Photo: Brett PetersPhoto: Brett Peters
Photo: ODFWPhoto: ODFW
![Page 40: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/40.jpg)
Photo: Danielle Reese
AcknowledgementsWDFW – Gene Orth, Matt Vander Haegen, Caitlin McIntyre, AnnMarie Prince, Mary Linders
Fort Lewis – Todd Zuchowski, Dave Clouse
Nature Conservancy – Cheryl Fimbel, Sanders Freed
Volunteers – Danielle Reese, Val Filer, Sara Gregory, Amy Stratton, Scotty Hardwick, Cindi Perez, Tadd Wheeler, Rachel Lipsky, Jesse McCarty
Committee – Steve West, Matt Vander Haegen, John Marzluff, Josh Lawler, Jim Kenagy
![Page 41: Eastern Gray Squirrel Ecology and Interactions with Western Gray Squirrels Aaron Johnston ∙ School of Forest Resources ∙ University of Washington Photo:](https://reader036.vdocuments.site/reader036/viewer/2022062409/56649d435503460f94a1fe50/html5/thumbnails/41.jpg)
Photo: Danielle Reese