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Noel DiPaola
Winter Ecology – Spring 2009
Mountain Research Station – University of Colorado, Boulder
Climate change responsible for declining
lemming population in Norway
✪Lemmings:
-Are subnivean creatures
-Typically experience cyclical vs. stable patterns
N/A. (2008). “Climate change pushing lemmings to cliff”. Retrieved on Feb. 26, 2009 from
http://news.bbc.co.uk/2/hi/science/nature/7711709.stm
Change in population dynamics
Leading to an overall drop in population
explosions.
We will be looking at what physical
environmental variables (in response to
climate change) are causing changes with
lemming population growth.
The subnivean space
1. Less protective snow cover
1. Increased hardness of snowpack
Note: Duration of the snow cover is not as important
Less Protective Snow Cover
★Increases predation rates
(May account for
40-70% of variation in cycles)
How would less snow affect predation rates?
-Less protection for small animals?
How would more snow affect predations rates?
-Will increase sowpack density
-Overall decrease?
 Doesn’t explain recent stabilization patterns
Increased Hardness of the Snowpack
Optimal subnivean space = TG snow conditions
Hardness develops because of the development of
EQ snow, lose of the dynamic temperature
gradient, and melting and freezing.
Halfpenny, J. C. & Ozanne, R. D. (1989). Winter: An ecological handbook.
Boulder: Johnson Publishing Company.
Kausrud, K.L., Mysterud, A., Steen, H., Vik, J. O., Ostbye, E., Cazelle, B.,
Framstad, E., Eikeset, A.M., Mysterud, L., Solhoy, T., & Stenseth,
N.C.
(2008). Linking climate change to lemming cycles. Nature,
256(10),
1692-1703.
Lima, M., Berryman, A. A., & Stenseth, N. (2006). Feedback structures
of northern small rodent populations. OIKOS, 112, 555-564.
Marchand, P. J. (1996). Life in the cold. Hanover: University Press of
New England.
Stabilization is one effect that climate change has
on subnivean species.
It occurs because of loss of snow coverage (which
in turn increases predation rates) and because of
the increased hardness of the snowpack
disallowing small mammals to burrow; ruining
their winter habitat so that there’s less of overwinter survival among species.