Transcript Caribou and Climate Change

Caribou and Climate Change
Questions and Antlers
Jim Bauserman, Hilary Hanson,
Chris Birks & Tom Amy
Rangifer tarandus
• Caribou (reindeer) found in
northern North America, Russia,
and the reaches of Scandinavia (3
of 7 subspecies of caribou
populate North America)
• Recently introduced satellite
mapping have better identified
elusive herds’ populations
• Despite increased awareness of
caribou patterns, data suggests
population decreases over time.
• What part does nature play?
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Seasonal Movements of
Satellite Radio Collared
Porcupine Caribou
1998 vs. 2008
(Satellite Imaging of Northern
Alaska and the Yukon &
Northwest Territories of Canada)
•Eight annual life cycle periods
by which to map caribou herds
(a)Winter 1998 (12/1/97-3/31/98) •Fall and spring migrations (the (a)Winter 2008 (12/1/07-3/31/08)
(b)Post-Calving and Movement
latter of which is followed by the (b) Post-Calving and Movement
(6/11-30-1998)
(6/11-30-08)
calving season)
•Caribou’s livelihood, along with
ability to repopulate, is incredibly
dependent on their habitat
Challenges to vulnerable herds’
ability to survive necessary
migrations and arduous birthing
cycles:
•Snow growth
•Seasonality of plants
•Presence of mosquitoes
Caribou and the North Atlantic
Oscillation (NAO)
• What is the NAO?
▫ Pressure gradient
between Iceland
and Azores
▫ Positive phase
produces warm,
wet winters in
northern Europe
• NAO index trending upward over past 30 years, most likely
due to climate change
• Impacts on caribou
▫ Calving
 Reduced calf weight and growth
▫ Plant access
▫ Spatial Synchrony
 Increases risk of extinction
Implications and Impact
• Predators
▫ Grizzly bears in the
arctic depend on
caribou for 80% of their
diet
▫ Wolves heavily
dependent on caribou
▫ Decreasing caribou
population intensifies
conflicts between
wolves and humans
• Plant Life
▫ Caribou circulate nutrients
around tundra
▫ Grazing moderates effects
of climate change on
tundra plant life
▫ Woody Shrub/Warming
Tundra Feedback Cycles:
 Warmer temperatures
contribute to woody shrub
overgrowth
 Woody shrub overgrowth
reduces tundra albedo,
raising temperatures
 Woody shrub overgrowth
traps more snow,
promotes soil warming
▫ Caribou weaken these
feedbacks by eating woody
shrubs
• Human Culture
▫ Caribou integral to culture of northern indigenous people
▫ Most important terrestrial food source for most northern
indigenous people
▫ Important particularly in remote areas with high food prices
Conclusions
• Climate change’s effects are
complex, often elusive
• Impacts on ecosystems can be
far-reaching