HUMAN SUPPRESSION OF SNOW AVALANCHES AND VEGETATION DYNAMICS IN

THE SUBALPINE ECOSYSTEM

by Nick LudolphWinter 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-vs-mountain-avalanche-control.html

THE AFFECT

OF SNOW

FENCES

(Fuchs et al 2006)

THE EFFECTS ON VEGETATION OF ALTERING AVALANCHE FREQUENCY

(Bebi et al 2009)

• Diversity• Structure of

Individuals– Small DBH– Shorter– Slower growth

rates• Structure of

Stands– Homogenous

• Frequency

WHAT I FOUND

AREAS FOR FURTHER STUDY• Land use change• Climate change

– Increases avalanche frequency (Huggel 2008)

• Longer term effects• Other Suppressiontechniques

Image: http://www.les-angles.com/hiver/images/stories/securite3.jpg

LITERATURE CITEDBebi, 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.