HUMAN SUPPRESSION OF
SNOW AVALANCHES AND
VEGETATION DYNAMICS IN
THE SUBALPINE
ECOSYSTEM
by Nick Ludolph
Winter Ecology – Spring 2010
Mountain Research Station, University of Colorado, Boulder
INTRODUCTION
• Initial Research Idea – Repeat
Photography
• Why it did not work
• My Next Idea – Transects
–Avalanche Danger Too Extreme
• Broader Picture – disturbance effects
summer vegetation dynamics too
• Literature Review – Human
suppression and vegetation
INTRODUCTION (CONT.)
• Question: What is the effect of human
suppression of the avalanche disturbance
on the vegetation dynamics of subalpine
forests?
• Hypothesis: Suppression of avalanches
will decrease the biodiversity and
ecosystem health found in avalanche
areas
• Alternate Hypothesis: Suppression will not
decrease biodiversity or ecosystem health
INTRODUCTION (CONT.): IMPORTANCE
• Lack of research in general (Bebi et al
2008)
• Effect on forest structure (Kulakowski et al
2006)
• Regular disturbance (Rixen et al 2007)
• Affects other forest disturbances (Veblen
et al 1994)
• Economics – is suppression necessary?
AVALANCHE SUPPRESSION
Image: http://deputy-dog.com/2008/03/man-vsmountain-avalanche-control.html
THE
AFFECT
OF
SNOW
FENCES
(Fuchs et al 2006)
THE EFFECTS ON VEGETATION OF
ALTERING AVALANCHE FREQUENCY
• Diversity
• Structure of
Individuals
– Small DBH
– Shorter
– Slower growth
rates
• Structure of
Stands
– Homogenous
• Frequency
(Bebi et al 2009)
WHAT I FOUND
AREAS FOR FURTHER STUDY
• Land use change
• Climate change
– Increases avalanche frequency (Huggel 2008)
• Longer term
effects
• Other
Suppression
techniques
Image:
http://
www.le
sangles.c
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LITERATURE CITED
Bebi, P., Kulakowski, D., & Rixen, C. (2009). Snow avalanche disturbances in forest ecosystems—State of
research and implications for management. Forest Ecology and Management, 257, 1883-1892. Retrieved
February 17, 2010, from the Web of Science database.
Fuchs, S., Thoni, M., McAlpin, M. C., Gruber, U., & Brundl, M. (2006). Avalanche hazard mitigation strategies
assessed by cost effectiveness analyses and cost benefit analyses—evidence from Davos, Switzerland.
Natural Hazards, 41, 113-129. Retrieved February 25, 2010, from the SpringerLink database.
Huggel, C., Caplan-Auerbach, J. and Wessels, R. (2008): Recent extreme avalanches: triggered by climate
change? EOS, Transactions, American Geophysical Union, 89(47), 469-470.
Ives, J. D., Mears A. I., Carrara P. E., and Bovis M. J. (1976). Natural Hazards of Mountain Colorado. Annals
of the Association of American Geographers, 66, 129-144. Retrieved February 25, 2010, from the Web of
Science database.
Kittel, T. (Director) (2010, February 7). Winter Vegetation Ecology. Winter Field Ecology. Lecture conducted
from University of Colorado, Niwot Ridge.
Kulakowski, D., Rixen, C., & Bebi, P. (2006). Changes in forest structure and in the relative importance of
climatic stress as a result of suppression of avalanche disturbances. Forest Ecology and Management,
223, 66-74. Retrieved February 16, 2010, from the Web of Science database.
Man vs mountain: avalanche control structures. (2008 February 3). Deputy Dog. Retrieved February 26,
2010, from http://deputy-dog.com/2008/03/man-vs-mountain-avalanche-control.html
Rixen, C., Haag, S., Kulakowski, D., & Bebi, P. (2007). Natural avalanche disturbance shapes plant diversity
and species composition in subalpine forest belt. Journal of Vegetation Science, 18, 735-742. Retrieved
February 17, 2010, from the Web of Science database.
Veblen, T. T., Hadley, K. S., Nel, E. M., Kitzberger, T., Reid, M., & Villalba, R. (1994). Disturbance regime and
disturbance interactions in a Rocky Mountain Subalpine Forest. Journal of Ecology, 82, 125-135.
Retrieved February 16, 2010, from the Web of Science database.