Small Mammal Module
Objective: determine small mammal responses to forest management
practices, at local and landscape scales
Responses: demography, habitat associations, spatial distribution
Components
-Long term grids: 21
21 grids,
grids, 44 forest
forest types
types
mammals,
mammals, vegetation,
vegetation, cone
cone production
production (in
(in progress)
progress)
-Terrestrial bird transects: 68
68 transects
transects (in
(in progress)
progress)
-Focal species: radiotelemetry
Dusky-footed
Dusky-footed woodrats
woodrats (completed)
(completed)
Northern
Northern flying
flying squirrels
squirrels (nearing
(nearing completion)
completion)
Small Mammal Module
1.6
northern flying squirrel
dusky footed woodrat
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
2003
2004
2005
2006
Year
2007
2008
Small Mammal Module
Overall Year Trends
25
Chipmunks
Mice
20
15
10
5
0
Small Mammal Module
Mice
80
mean conifer cone abundance
annual snow fall
mean mouse abundance
60
40
20
0
2003
2004
2005
2006
Year
2007
2008
Small Mammal Module
Dusky-Footed Woodrat
4.0
3.5
Experimental Control
All Control
Group Select
Heavy Thin
Light Thin
Treatment
Mean Abundance
3.0
2.5
2.0
1.5
1.0
0.5
0.0
2005
2006
2007
Year
2008
Small Mammal Module
Northern Flying Squirrels
3.5
Experimental Control
All Control
Group Select
Heavy Thin
Light Thin
3.0
Mean Abundance
2.5
Treatment
2.0
1.5
1.0
0.5
0.0
2005
2006
2007
Year
2008
Small Mammal Module
Mice
25
Experimental Controls
All Controls
Group Select
Heavy Thin
Light Thin
Mean Abundance
20
Treatment
15
10
5
0
2005
2006
2007
Year
2008
Northern Flying Squirrel and
Forest Management
•
•
•
Home Range
Habitat Assessment
Den Trees
© Sean Bogle
Authors: Jaya Smith, *Doug Kelt, *Dirk Van Vuren, *Michael Johnson
* Co-Principle Invetigators on the Plumas Lassen Administrative Study Small Mammal Module
Why Flying Squirrels?
• Implications for logging:
– Keystone Species
– Prey of Spotted Owl
– Managers interested in flying squirrel use of
forest
Home Range
• Useful tool that allows managers to
determine how much contiguous area an
animal needs to survive
• Index of habitat quality
Methods
… and Radiotracking!
Trapping
Collaring
Telemetry/Home Range Analysis
Concurrent
Triangulation
Home Range
Estimates
Modified from James Wilson
Locations
• Achieved from
triangulation
• Best estimate for
where the animal is
located
• Allows generation of
home ranges
Home Range
• Helps forest
managers make
decisions:
– How much area is
needed?
– What habitat types are
in the home range?
Home Range Area (Fixed Kernel)
• Area = 27.2 ± 3.7 Acres
Comparison Across Studies
120
120
Northern California
100
100
Acres
Acres
80
80
Oregon
60
60
40
40
20
20
00
--
Male
Male
Female
Female
Male
Male
Female
Female
Witt
Witt 1992
1992 Martin
Martin and
and Anthony
Anthony Wilson
Wilson et
et al.
al. 2008
2008
1999
1999
Study
Study
Male
Male
Female
Female
This
This paper
paper
Overlay Habitat Map with Home
Range and Points
+
=
Habitat Map
• Modeled using California Fish and Game’s
Wildlife Habitat Relations (WHR) model from
Vestra habitat layer for Plumas National Forest
• Categories in our area included:
– Riparian
– Sierra mixed conifer (small, medium and large)
– Monocultures
– Wet meadows
– Barren areas
– Chaparral
– Bodies of water
Habitat Preferences
• Conduct Habitat
Assessment on two
scales:
– 1-Across the forest
(Broad)
– 2-Within the home
range itself (Narrow)
• Compare Available
habitat with Used
habitat
Habitat Preferences
•
Two most important habitat types:
– Broad-Scale Importance:
1. Large Sierra mixed conifer
2. Medium Sierra mixed conifer.
– Fine-Scale Importance:
1. Large Sierra mixed conifer
2. Medium Sierra mixed conifer
Habitat Preferences
• Take-home message:
– Northern flying squirrels prefer mature forests
over forests with small immature trees relative
to abundance in Plumas National Forest.
X
• Den Tree;
Methods
– Telemetry/Homing
Telemetry/
Homing
Den Trees Used
92 Flying
Squirrel Dens
Measured
Black Oak
White Fir
Ponderosa Pine
Lodgepole Pine
Douglas
Red
Fir
Fir
Jeffrey Pine
Bigleaf Maple
Incense Cedar
Use
Availability
Use Versus Availability
0.4
0.4
Y Data
Data
Y
0.3
0.3
Available
Available
Used
Used
0.2
0.2
0.1
0.1
0.0
0.0
White
White Fir
Fir
Douglas
Douglas Fir
Fir
Black
Black Oak
Oak
Red
Red Fir
Fir
X
X Data
Data
92 Used den trees
4,188 Available trees measured!!
Tree Size
• Two Categories Based on Forestry
Practices
– Hardwoods (Oak, Maple, Dogwood)
– Conifers (Pine, Fir, Cedar)
Hardwoods
Use Versus Availability of Hardwoods
Proportion Used
0.4
Availability
Use
0.3
0.2
0.1
0.0
5
4
10
15
6
20
8
25
30
35
40
45
50
20
10
12
14
16
18
Tree Size (cm)
(Inches)
55
22
60
Hardwoods
Use Versus Availability of Hardwoods
Proportion Used
0.4
Availability
Use
0.3
Small
Large
0.2
0.1
0.0
5
4
10
15
6
20
8
25
30
35
40
45
50
20
10
12
14
16
18
Tree Size (cm)
(Inches)
55
22
60
Conifers
Use Versus Availability of Conifers
0.5
Proportion
0.4
Available
Use
0.2
0.1
0.0
30 40 50 60 70 80 90 100 110 120 130 140 60
8 12
4 20
16 20 24 28 32 36 40 44 48 52 56 150
10
Tree Size (cm)
(Inches)
e
rg
La
be
tim
aw
r
lS
al
be
Sm
tim
le ngs
Po pli
Sa
Conifers
Use Versus Availability of Conifers
w
Sa
be
tim
r
0.5
r
Proportion
0.4
Available
Use
0.2
0.1
0.0
30 40 50 60 70 80 90 100 110 120 130 140 60
8 12
4 20
16 20 24 28 32 36 40 44 48 52 56 150
10
Tree Size (cm)
(Inches)
Den Trees; Use vs Availability
•
Den Tree Ranking (most to least important):
1.
2.
3.
Large hardwood (≥13 inch dbh)
Large sawtimber (Conifer ≥21 inch dbh)
Small hardwood (4-13 inch dbh)
4. Small sawtimber (Conifer 11-21inch dbh)
5. Poletimber (Conifer 3-11 inch dbh)
6. Sapling (Conifer and hardwood 0-3 inch dbh)
Summary
• Northern Flying Squirrel:
– Home range = 27.2 ± 3.7 Acres
– Preferred habitat types are large and medium
Sierra Mixed Conifer
– Preferred den trees are large hardwoods and
conifers, and small hardwoods
Informed Forest Stewardship