Winter Controls on the Distribution of Arboreal Hair Lichens in the Niwot Ridge Biosphere Reserve

1. Winter Controls on the Distribution of Arboreal Hair Lichens in the Niwot Ridge Biosphere Reserve Keli Baker Winter Ecology Spring 2013 Mountain Research Station, University of Colorado, Boulder

2. Background • “Old Man's Beard” • Arboreal hair lichen – Usnea • Conifer substrate • Get most of their winter moisture from winter snow melt (Campbell et al, 2001). • More lichen in subalpine?

3. Introduction • Question: What is the distribution and abundance of arboreal hair lichens in the area surrounding the MRS and what winter environmental factors affect their distribution?

4. Possible Winter Controls • Hypothesis: The distribution of the arboreal lichens will be affected by snow depth, tree species, wind exposure, stand density and elevation. • Environmental factors change with elevation: • Precipitation • Temperature (Veblen, 1986) • Tree species and stand density (Veblen, 1986)

5. Methods • Visually measured lichen abundance • Nine 1m x 50m plots • Elevation range: 3,050m (10,000 ft) to 3,200m (10,500 ft) • Developed sale to quantify lichen abundance • Assigned each tree an abundance level from 0 to 4 • Online chi-square calculator comparing: • lichen abundance level frequency • elevation • tree species

6. Results • Significant correlation between elevation and lichen abundance • p<<0.001 • Chi square: 105.252 • Degrees of Freedom: 16

7. Results • Significant correlation between tree species and abundance • p = 0.00073547 • Chi square: 14.43 • Degrees of Freedom: 2

8. Results • Significant correlation between tree species and elevation. • p = 0.00256282 • Chi square: 23.7 • Degrees of Freedom: 8

9. Discussion • Lichen abundance affected by: • Preceipitation – in general, more at higher elevations • Elevation – microclimate changes • Stand Structure – density, species composition • Lichen prefers subalpine fir • Lichen found mostly in subalpine

10. Conclusion • Elevation affects lichen abundance because of micro-environmental changes associated with elevation gradients. • Stand structure effects lichen abundance with more lichen: • On subalpine fir substrate • In denser stands • Lichen abundance is confined mostly to subalpine elevations

11. Works Cited • Gough, L. P. 1973. The distribution of corticolous cryptogams on Pseudotsuga menziesii (Mirb.) Franco and Abies lasiocarpa (Hook.) Nutt. in the Front Range, Boulder County, Colorado. Ph.D. Thesis, University of Colorado, Boulder. • Berryman, S. et al. 2006. Estimating Epiphytic Macrolichen Biomass from Topography, Stand Structure and Lichen Community Data. Journal of Vegetation Science 17: 157-70. Wiley Online Library. 24 Feb. 2009. Web. • Campbell, J. et al. 2001. Canopy Microclimate and Arboreal Lichen Loading in Subalpine Spruce–fir Forest. Canadian Journal of Botany 78: 537-55. NRC Research Press. University of Northern British Columbia, 3 May 2001. Web. DOI: 10.1139/cjb-79-5-537 • Peet, R. 1981. Forest Vegetation of the Colorado Front Range: Composition and Dynamics. Vegetatio 45: 31-75. • Veblen, T. 1986. Age and Size Structure of Subalpine Forests in the Colorado Front Range. Bulletin of the Torrey Botanical Club 113: 225-240.

12. Works Cited Preacher, K. J. (2001, April). Calculation for the chi-square test: An interactive calculation tool for chi-square tests of goodness of fit and independence [Computer software]. Available from http://quantpsy.org.