1. Old Man’s Beard Lichen (Usnea) size across its elevation range at Niwot Ridge, Colorado
Kelsey Bohanon
EBIO : Winter Ecology
Spring 2017
CU Mountain Research Station

2. Introduction Question: Does elevation affect the size of Usnea lichen?
Hypothesis:
Null: there is no relationship between lichen size and elevation
Alternate: there is a relationship between lichen size and elevation

3. Introduction Background
lichen growth rate is higher in favorable conditions (Rolstad and Rolstad 2008)
usnea lichens exist in environments sensitive to climate change (alpine, arctic, Antarctic)(Halonen 2000)
Since the early 1980s, researchers have been discovering a link between lichen growth and air pollution, establishing lichens as good bioindicators
identifying optimal habitat helps to establish effective air quality bio-monitoring stations (Shrestha et al. 2012)

4. Introduction Climactic factors that change with elevation:
Solar radiation
Barometric pressure
Temperature
Range, diurnal, seasonal
Wind
Precipitation
These factors affect both lichen growth and air pollution
UV:
Increased, which can increase photochemical smog
Pressure:
Changes the density of pollutants in PPM
Temp:
Decrease, slows production of photochmical smog
Wind:
Disperses pollution
Precipitation:
Removes particulate pollution from air
How these are affected at Niwot:
Wind, precip different on E/W side
Input of pollutants from E

5. Methods Sampling design
Elevation range from 3050m to 3300m (subalpine forest)
Divided into 5 blocks of 50m range
2 randomly selected transects per block
Elevation of each trasect within each block was random
Side of trail was random
Direction (e/w, n/s was random)
Not replicated

6. Methods Lichen measurements:
5 evenly spaced trees (with lichen) per transect
5 representative bunches per tree
L*W
Choosing trees and choosing lichen bunches was not randomized, possibly introducing some bias

7. Results
P-value: 1.213e-5***

8. Results Analysis: Used R to run an ANOVA
Had to eliminate upper end of elevation ( m) because there was no lichen
Lichen is biggest in middle of elevation range
mid-range elevation is optimal habitat
Due to potential bias in sampling, should have done a repeated measures

9. Discussion Potential biases in data
There must be some other limiting factor which affects lichen health in its range, that is also related to elevation
Climactic factors (UV, pressure, temp, wind, precip)
Forest structure
Nutrients
Other things that could be affecting lichen health:
Climactic factors
Precip
Min and max temps
Solar radiation
Moisture
Topographic factors
Elevation
Slope
Aspect
Land forms
Previous study found that lichen distribution in White River Ntl Forest found the best model for predicting distribution included 4 climactic factors: min/max temp, precip, SR
Of these, min/max temp the most important (Shrestha et al. 2012)
Forest structure
Density, species composition, competing lichens, barriers to spore dispersal/colonization
Nutrient availability
Previous experimental study using cultures found significant effects of carbon, sucrose, polyethylene glycol, glycine on various aspects of lichen health (growth rate, biomass, etc)(Behera et al. 2009)

10. Discussion Future studies: Repeat study in other areas
With different exposures to air polluition
Measure aspects of air pollution at elevation
Repeat study with different predictor variables
Climactic or topographic
Compare air quality to climactic or topographic factors

11. Discussion Why? Human health Ecology
Increased human activity at elevation
Climate Change
Long term studies
Human
- increased absorption of toxins due to physiological changes at altitude
increased blood flow
redistribution of blood flow away from skin towards core
increased respiration due to lower levels of oxygen
Ecology
confinement/entrapment in an inversion layer
pollutants may cause exaggerated changes in intricately balanced systems (EPA 1978)

12. references
Behera BC, Verma N, Sonone A, Makhija U Optimization of culture conditions for lichen Usnea ghattensis G. Awasthi to increase biomass and antioxidant metabolite production. Food Technol. Biotechnol. 47:7–12.
EPA Altitude as a Factor in Air Pollution.
Halonen P STUDIES ON THE LICHEN GENUS USNEA IN EAST FENNOSCANDIA AND PASIFIC NORTH AMERICA Department of Biology STUDIES ON THE LICHEN GENUS. Univ. Oulu, Finl.
Henderson A Literature on Air Pollution and Lichens. Lichenologist 32:89–102.
Rolstad J, Rolstad E Intercalary growth causes geometric length expansion in Methuselah’s beard lichen ( Usnea longissima ). Botany 86:1224–1232.
Shrestha G, Petersen SL, St. Clair LL Predicting the distribution of the air pollution sensitive lichen species Usnea hirta. Lichenol. 44:511–521.