Habitat Use and Ecology of theHabitat Use and Ecology of theNorthern Flying SquirrelNorthern Flying Squirrel

Todd M. WilsonTodd M. Wilson

USFS, PNW Research StationUSFS, PNW Research Station

Pacific Northwest

Simplified to ComplexSimplified to Complex

13 ha Stand (32 acres)

Variable-density Thinning

Legacy ForestLegacy Forest

Open-Cut

Light ThinControl

Pre-treatment

Timber ForestTimber Forest

Open-Cut

Light ThinControl

Pre-treatment

Thinning

AssociationsAssociations

Understory cover

Patch-level changesin vegetation

Large snags

Large treesEricaceous

shrubs

High canopy cover

Nearness to conifers

Nearness to water

Abundant coarse woody debrisLarge coarse

woody debris

Increased litter depthAvailability of fungi Stand Age

Hypothesized Limiting Hypothesized Limiting FactorsFactors

FoodFood DensDens PredationPredation CompetitionCompetition

Forest Structuring Forest Structuring ProcessesProcessesCrown-class Differentiation Understory Development

Canopy Stratification Decadence

Classifying Stands as Classifying Stands as High or Low AbundancesHigh or Low Abundances

10-m Intercept

Variance inLive Tree d.b.h

CanopyGaps

Olympic Peninsula

(smallest white patches ca. 10m x 10m gaps)

Vertical LayersVertical Layers

5

1015

2025

Structure-Predation Structure-Predation HypothesisHypothesis

Fore

st

Str

uctu

reF

ore

st

Str

uctu

re

Detection RiskDetection Risk((Visual/Aural/ScentVisual/Aural/Scent))

OR

High

Low

OR

Attack RiskAttack Risk

Safe

Unsafe

Very Unsafe

Mixed

Squirrel Space UseSquirrel Space Use

Den

Where do we find lots of Where do we find lots of flying squirrels?flying squirrels?

Where do we find few (if Where do we find few (if any) squirrels?any) squirrels?

What about big trees, What about big trees, snags and CWD?snags and CWD?

Stay tuned for Stay tuned for

Part IIPart II