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Grizzly Bears in the Kootenays
Michael ProctorTrans-border Grizzly Bear Project
Current and historical North American grizzly bear distributionShaded area is current distribution
Trans-border Grizzly Bear Project A partnership working on both sides
of the Canadian – US border
• Team Canada
• US Fish & Wildlife Service
• Idaho Fish & Game
What we do: Comprehensive strategy of enhanced management
Reduce human-caused mortality Improve linkage
Augmentation
Education
Guarantee habitat security
South Purcell and South
Selkirk Trans-border
populations:
small,
fragmented,
and threatened
South Purcell/Yahk
40 bears
Declining 3% annually
Regional grizzly bear fragmentation in southern CanadaInternal dotted lines represent limited female movement – solid yellow (& brown) limited male and female movement, red lines are highways
Implications
50
30
40
75
30
75
Small Pops - urgent need for linkage mgmt
500
470+
300
500+
Large Pops - consider linkage mgmt
Yahk GBPU
87
92
5820
Research estimate1
Population estimates for GBPUs in Purcell Selkirk region
1 Proctor et al. 2007
BC Gov estimate
(159)
(148)
(44)(58)
Hunt quota lowered by BC gov
Hunt rate lowered by BC gov
20-24 grizzly bears in unit
3 females known dead in last few years + unknown (1:1 ratio)
25% are adult females - 4-5
Dearth of females in Yahk GBPU
Yahk GBPU
Live capture 1 female capture / 74 trap nights 1 Grizzly capture / 41 trap nights
DNA surveys 26 female captures / 3 years of surveys
DNA surveys 2 female captures / 3 years of surveys
Live capture 1 female capture / 568 trap nights 1 Grizzly capture / 95 trap nights
S Purcell GBPU
Yahk GBPU
Dearth of females in Yahk GBPU supporting evidence
Fragmentation – female isolated
Access management standards in US
What went into them
Accepted research
Bears avoid roads and human featuresMotorized vehicles of all kinds and
shapes Human developments accompanied by people More human traffic = more avoidance
Avoidance buffer is up to 500m
Adult females are most important to a population’s health
Adult females select habitat with some % (55-68) of secure area
Secure habitat defined as areas with no human access (habitat > 500m from motorized access)
Mace et al. 1996
Female HRs
Larger study area
Are there differences in habitat where females chose to live?
YES
They contained 56% secure areas no motorized access
And average road density ~0.6 km/km2
Mace et al. 1996
Legal standard
68% of BMUs to be “core” (0km/km2)
Average road density – 0.6 km / km2
19% can have > 1 km / km2
19% can have > 2 km / km2
Clear conclusion – security selected by females
more traffic = more avoidance
There is a relationship between human access, mortality, and displacement
US Purcell, and Selkirk Mts
Concluded 55% core was adequate no more than 33% > 1 km / km2 no more than 26% > 2 km / km2
Wakkinen and Kasworm 1997
Roads in the Yahk area
Grizzly bear management units ~ Size of female home range, used to spread access management around GBPU
Grizzly bear management units
Roads in the Yahk area
Roads in the broader Yahk region
Roads in US Yaak
Note effect of access management (closed roads) on US Yaak road density
Roads in the broader Yahk region
Local female grizzly bears selection of “core habitat” as a % of home range core habitat = habitat > 500m from a motorized road
0.38Terri trouble keeping offspring alive
0.45Marilyn died before reproducing
0.54Maeve survived & reproduced
0.44Kelly survived & reproduced
0.55Irish survived & reproduced
% core habitatFemale GB
Yahk GBPU average 0.29
S Purcell GBPU average 0.53
36%
34%
21%
39%
34%
Grizzly bear management units and % core
The goal = 0.50 – 0.60 % core to support females that survive and reproduce
Looking for solutions
Resource Selection Function (RSF)
modeling
To identify high quality grizzly bear habitat for consideration for access management
18,000 GPS telemetry locations for 13 grizzly bears
4 females
9 males
Trans-border Grizzly Bear Project research
Variables Variables
Land cover Ecological
Alpine Elevation
Avalanche Curvature Index
Barren Terrain rugged index
Burn Greenness
Riparian Slope
Forest cover Solar radiation
Forest age Human
% crown closure Human developments
Old forest Highway
Young forest Roads
Recently logged Parks
Cedar - Hemlock
Spruce - Sub alpine fir
Douglas Fir
Lodgepole pine
White pine
Deciduous
Input variable for Resource Selection Function models – habitat modeling
Logistic regression models
Exp (β0 + β1*Var1 + β2*Var2...)
1 + Exp (β0 + β1*Var1 + β2*Var2…)Prob (occur) =
Higher quality grizzly bear habitat (green shaded)
Black polygons encompass “core” habitat. Blue are Hwy 3 linkage areas to consider access management (AM)
To use as options for AM to optimize gain for female grizzly bears.
Green shaded areas are a composite of male and female habitat during spring and fall. Sex and season partitioning is possible
Recommended