Arctic Fox versus Red Fox in the Canadian arctic: Is there a clear winner after 38 years of monitoring in

the warming northern Yukon?

1Chaire de recherche du Canada en conservation des écosystèmes nordiques et Centre d'études nordiques, Université du Québec à Rimouski, Rimouski, Québec2Private Contractor, Whitehorse, Yukon3Wildlife Conservation Society Canada, Whitehorse, Yukon

6 February 2009 - Québec

Daniel Gallant1, Dominique Berteaux1, Brian G. Slough2, Don G. Reid3

Introduction

* 20th Century Climate: 1900–1975: Slow warming,

large fluctuations in temperature.

1975–today: Rapid warming (0,2°C/10 year).

• Global surface temperatures: Probably within 1 °C of having attained the maximum surface temperature of the past 1 million years.

(Hansen et al. 2006, PNAS)

Introduction

* Shifts in species distributions and theirphenology match 20th century climate trends:

- Over 1700 species analysed.

- Average range shifts: 6,1km /decade toward poles.

(80% of shifts in expected direction)

- Spring events: Timing is 2,3 days earlier /decade.

(87% of shifts in expected direction)

(Parmesan & Yoge 2003, Nature)

* Shifts in plant and animal distributions:- Many projection studies have been done

Introduction

* 20th Century: Northward Expansion of the Red Fox:

Canadian Arctic : chronology from Hudson Bay Company trading posts and Royal Canadian Mounted Police detachments.

* Simultaneous phenomena observed in the former U.S.S.R.

(MacPherson 1964, J. Mammal.)

(reviewed in Chirkova 1968, Problemy Severa)

Introduction

Remains of tools made from animal bones and antlers found at caribou hunting site

* Archaeological diggings at Trail River, North Yukon:

* Red fox mandibles

* Radiocarbon dating:

- 1810 to 1435

(Nagy 1988, thesis, Simon Fraser University)

Introduction

* Direct Competitors: large food overlap, occupation of arctic fox den by red foxes.

* Red Fox is Dominant: chases, attacks, kills arctic fox.

*Displacement by Interference Competition: A question of whether the environment permits red fox establishment.

(Pamperin et al. 2006, Arctic)

* Northern hemisphere: warming more important at higher latitudes.

* Western Arctic: Northern Yukon is in region having highest level of warming in North America.

• ≤ 2°C of annual surface temperature anomaly

(2001-2005 VS 1951-1980)

Introduction

(Hansen et al. 2006, PNAS)

Introduction

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1960 1970 1980 1990 2000 2010

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1960 1970 1980 1990 2000 2010Tem

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1960 1970 1980 1990 2000 2010Tem

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1960 1970 1980 1990 2000 2010

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Year

July

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Komakuk Tuktoyaktuk

Temperature = 0,04 (year) - 77,83R2 = 0,132 ; F = 6,82 (sig. = 0,012)

Temperature = 0,01 (year) - 46,06R2 = 0,002 ; F = 0,08 (sig. = 0,781)

Temperature = 0,035 (year) - 58,29R2 = 0,073 ; F = 3,71 (sig. = 0,06)

Temperature = 0,079 (year) - 183,29R2 = 0,093 ; F = 4,72 (sig. = 0,035)

Nothern Yukon:

- Longer presence of red fox

- Higher warming rate

* Change in the Arctic-Red fox community?

Introduction

Den Surveys (species occupation):

- Comparison of current status of both species with past surveys.

Introduction - Hypotheses

Hypothesis A: The warming climate of the northern Yukon is associated with an increased presence of the red fox in the tundra ecosystem.

Prediction 1: The number of dens used by red foxes has increased in 4 decades.

Hypothesis B: Arctic foxes have suffered a range contraction over the last 4 decades as a result of the presence of the physically dominant red fox.

Prediction 2: The number of dens used by arctic foxes has declined.

Prediction 3: The number of arctic fox dens later found occupied by red foxes is higher than the inverse situation.

Study Area - Yukon Coastal Plain Ecoregion

* Herschel Island

- 101 km2

* Mainland Plain

- 2450 km2

Methods - 2008 Den SurveysCoastal Plain :

* Aerial Helicopter Survey (1-6 July 2008)

- North-south transects at 500 m intervals

- Speed: 100 km/h

- Altitude: 50 - 100 m

- One observer each side

Herschel Island :

* Ground survey (36 person-days in June)

- 500-m spaced linear transects

- Detours and spot checks to cryptic areas

- All dens visited a second time in late summer

• Landings/visits at each den, documenting:

- Occupying species (red, arctic fox)

- Visual observations, inspections of fur in burrows

- Den status (inactive, used, natal)

- Detection of usage: fresh scats and diggings, fur, sightings

- Detection of young: sound, tracks, sightings

- Number of extant burrows

Methods - 2008 Den Surveys

* 1971-1972 (Ruttan and Wooley)- Preliminary search by fixed-wing aircraft,

intensive ground checks by helicopter survey (August).

- 1972: Multiple ground checks and visits to dens by helicopter, dog team, snowmobile and foot (May-September).

Methods - Past Den Surveys

* 1984-1990 (Slough, Smits, et al.)- 1984: Systematic helicopter survey as in 2008,

all dens ground-checked (July).

- 1985, 1986, 1988, 1989, 1990: Opportunistic ground checks at known dens in (July). Only Herschel Island done in 1986 and 1990.

- 1987: Stratified random block helicopter survey (July). All known dens ground-checked.

Methods - Past Den Surveys

Results

* Systematic den-search- Herschel Island : 101km2 by foot.

- Mainland: 560 km2 by aerial transects

(rest of mainland: targeted visits to dens)

* Herschel Island Dens:- 26 / 38 dens found (from 1984-90)

- 33 new sites found

- Total 59 dens (37 dens ≥ 3 burrows)

* Mainland Dens:- 45 / 55 dens found (from 1984-90, 9 found collapsed )

- 54 new locations (old dens complete/partial collapse)

- Total: 76 dens (53 dens ≥ 3 burrows)

Results - Den usage* Summer status of

inspected dens for aerial surveys conducted in the northern Yukon over a 4-decade period.

Sign Tests : change in the frequency of dens used by arctic and red fox (common densbetween periods):

Arctic Fox1971-72 VS 1984-90: P ≥ 0,991984-90 VS 2008: P = 0,122Red fox1971-72 VS 1984-90: P = 0,251984-90 VS 2008: P ≥ 0,99

Results - Dynamics of Den Usage

* Dynamics of den usage by arctic and red foxes for 51 dens inspected in summer on ≥ 4 particular years and representing a ≥20-year span.

Scott & Seber comparison of proportions: p1-p2 = 0.0196 ± 0.115, P > 0.05

Results - Reproductive Dens

* Number of reproductive dens of red and arctic foxes relative to total number of dens visited on Herschel Island and the northern Yukon mainland.

Results – Den Usage History

C

16 km

A

B

C

B

A

Results – Red Fox Den Usage Dynamics

16 km

1972

1985, 1987-89

2008

2008

1972

1971

1988, 2003 1984-85, 2008

1972

1971-72, 2008

1972

1972

Results – Arctic Fox Den Usage Dynamics

16 km

Reproductive dens 2008

Discussion

* The 2008 den survey shows that in the Yukon Coastal Plain:

- Red fox presence at dens has not increased

- Arctic fox presence at dens has not declined

- Red foxes are not taking over arctic fox dens

* Both hypothesis rejected:

In this region, the fairly intense climate change does not appear to have caused changes in the range and the relative abundance of these competing predators.

Discussion

Result: Summer temperatureBiotic Hypothesis: Increased ecosystem productivity

Result: Winter environmental variablesAbiotic-Biotic Hypothesis: Winter severity (physiological and food shortage effects)

(Hersteinsson & MacDonald 1992, Oikos)

(Bartoń & Zalewski 2007, Global Ecol. Biogeogr.)

Discussion

* Canada: No recent appreciable changes at several sites.- Herschel, Bylot, Churchill

* Fennoscandia: Dominated by Red Fox.- Food availability: Fall and Rise of Reindeer populations. - Rise of Red Fox, no recovery of arctic fox numbers.

* Russia: Recent arrivals of Red Fox a some sites

(Selås and Vik 2007, Biodivers. Conserv.)

Discussion

*ArcticWOLVES Sites & Red Fox trends (or lack thereof):

- Comparison & Integrationof information on prey-base composition and changesand their relative abundances.

- Put Secondary Productivityand its winter accessibility at the forefront.

* Fieldwork: François Racine, Guillaume Szor, Helen Slama, Scott Gilbert

* Logistics: Florient Koch, Richard Gordon and staff at Qikiqtaruk Territorial Park

* Funding and supporting agencies:

Acknowledgements