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