1. Lichen Growth in the Presence of a Road on Niwot Ridge
Hi everyone, my name is Anna-Elise Smith. For my project, I studied the effect of the road running across Niwot Ridge’s traffic on lichen growth on the trees near C1.
Anna-Elise Smith
Winter Ecology, Spring 2017
Mountain Research Center, University of Colorado Boulder

2. Introduction What are lichen?
Sensitivities to heavy metals sun and wind
Biomoniters for ecosystems
Snow mobiles on the ridge
While walking in the subalpine forests of the Front Range, one might spot various lichens living on trees. Lichens are an interesting life form, described by the USDA Forest Service as “a symbiotic partnership of two separate organisms, a fungus and an alga.” The fungus gives the lichen its structure and fruiting bodies while the alga or cyanobacteria photosynthesizes and contributes to energy production (USDA Forest Service). Lichen are very sensitive to pollution and environmental factors like sun and wind. Lichens tend to metabolize any soluble materials which can greatly reduce their fitness in the case of pollutants (Brown and Beckett, 2007). Lichen are used as biomoniters to predict the relative “health” of an ecological community. Heavy metals from vehicles cause a decrease in photosynthetic ability of lichens and eventually break down the cells (Garty, 2010). On Niwot Ridge, various vehicles frequent the trail in the winter. Localized pollution from four wheelers, snow mobiles and ATVs could include exhaust and particulates kicked up in their wake. It is important to determine how this traffic may be effecting the ecosystem. Lichen presence is a good way of determining if there is significant pollution from exhausts of winter vehicles on the trail. My question I aimed to answer with my research is how does the presence of a frequented road impact the growth of lichen on Subalpine Fir and Lodgepole Pine on Niwot Ridge?
I also wondered how the side of the road impacts lichen growth. Lichen is also very sensitive to sun and wind exposure. I hypothesize that sun exposure effects the amount of lichen less than wind but still has an effect that will be measurable by observing more lichen on south facing branches. Campbell & Coxson noted that clumps of trees showed higher concentrations of lichen on branches than solitary trees in the forest, which I believe could be attributed to wind exposure killing lichen on solitary, exposed trees. Too much sunlight may also decrease the amount of lichen as found by Bejerke et. al. who exposed lichen to excess UV B light and did not find significant differences between the control and experimental sites, except that the enhanced UV B site had slightly decreased photosystem II efficiency. Previous student Keli Baker set out to find the effects of wind exposure, precipitation and elevation and did not find conclusive results about the effects of wind exposure. I hypothesize that wind will have a larger and negative impact on lichen growth, which will be measurable by observing less on west facing branches and less in the edge forest than the clustered forest. The null hypothesis would show that there is no significant difference in lichen growth between north, south, east and west facing branches and no significant difference between the clustered transect and the open transect.
USA Forest Service
Brown and Beckett, 2007
Garty, 2010

3. Introduction
How does the presence of a frequented road impact the growth of lichen on Subalpine Fir and Lodgepole Pine on Niwot Ridge?
Does the side of the road which the tree grows have an effect?

4. Introduction
Null Hypothesis: There is no significant difference in lichen growth between trees lining the road and trees deeper in the forest.
Alternate Hypothesis: Trees lining the road will have significantly less lichen than trees in the interior forest.

5. Methods 4 sites, 2 roadside, 2 interior for repetition
3 trees per site
5 branches per tree
ANOVA
Limitations
For my methods, I hiked up to C1and measured four sites, 3,200 meters above sea level (10,500 feet). There were two sites, one on either side of the road, that were 50 meters. From those two sites I went 25 meters into the woods and had 50 meter long sites parallel to the roadside sites. I used a random number generator to chose 3 spots along the 50 meter transect (the numbers counted by 5s from 5 – 50). Once I got the generated numbers, I chose a tree closest to the random generated meter. For each transect there were 3 trees. Each tree I counted lichen growth on the lowest 5 branches. I coded this binary, yes or no lichen growth. I also recorded which direction the branch faced as I went along. Once I collected the data, I entered it into Excel and uploaded it to R studio. From there, I preformed analysis of variance tests across multiple variables and graphed my results. Limitations in my methods include small smple size and inability to control or wind and sun exposure (due to branch aspect).

6. Mean Number of Branches with Lichen by Treatment
This graph displays the mean number of branches with lichen on them per tree on the roadside sites versus the interior sites. This was the main question asked in the experiment: is there a difference in lichen growth between roadside trees and interior forest trees and what is the effect of the road? There is a difference in means of 1, but the difference is not statistically significant (p-value of 0.256). The standard error bars are also large, 1.66 and 0.66 respectively.
Results

7. This graph displays the mean number of branches with lichen per tree at each site. The standard error bars are large in each sample. There appears to be an effect where interior has more lichen than roadside samples and where the West side of the road has more lichen than the East side oft the road. However, the difference is not statistically significant. The p-value of the effect of Road v Interior was and the p-value of the effect of West versus East was The ANOVA found that the interaction between the two variables was even less significant with a p-value of
Results

8. Branches with Lichen and Their Aspects
To deeper explore the effect of aspect, I analyzed the aspect of each branch and whether it had lichen or not. Taking into account the large error bars, all of the aspects show about one half with lichen and one half without, with North and South facing branches having a bit less lichen than the other directions. You can see the wide standard error especially in the North and South facing branches. There were many more East and West facing samples. But, the sampling was unequal throughout the four sites. For example, the interior samples on the West side of the road had no West facing branches on any of the three trees. No other obvious patterns were observed within the plots.
Results

9. Results No significant difference in interior or roadside samples
No significant difference between branch aspect
Direction of trend: more lichen in interior forest

10. Discussion Effect of Road Direction of Relationship Sample Size
The effects of wind, solar exposure
and branch aspect
There was less lichen growth road side than interior. However, the difference was not statistically significant. It may still be pointing to a general trend of less lichen growth road side. The direction of the relationship is consistent with my hypothesis, but statistical testing proved the null hypothesis that there was no significant difference in lichen growth between trees on the roadside and interior.
My sample size was rather small, which may decreased the validity of my results. Wind and solar exposure could have helped confound the results. As found by Campbell and Coxson trees in groups had more lichen than single trees likely due to less wind exposure so this could explain why the interior trees had more lichen.
Another confounding variable as displayed on the previous graphs is branch aspect. Trees on the East side of the road has less lichen but it was also not statistically significant. This could have to do with the direction of storms coming in to from the West. The individual branch aspect results did not show a big difference between the four cardinal directions. With a larger sample size, perhaps they would have. Some trees also had no branches on one side of the tree all together.

11. Discussion Future studies and further explorations Locations over time
Wind, Solar and Aspect
To get more clear results, I suggest we continue to research this but with many more points along the road. To better understand the effect of traffic, we could sample busier roads and walking only trails to compare and contrast the effect on lichen growth on nearby trees. Ideally, we could do a long term ecological study on a specific alpine road/trail and track use over time as well as lichen growth and degradation.
The effect of branch aspect as well as the effects of wind and solar exposure should be studied more closely. In my experiment, there were some trees that no branches on one side all together. Whether a branch is facing the sun or exposed to the wind scour could make a big difference in lichen growth. It would be difficult to control for this variable, so by getting samples from branches of every aspect in the same location could help tease out the effect of branch aspect versus the road. By measuring the wind and solar exposure each branch experience in the next experiment, it could be controlled for. Controlling for aspect does not necessarily control for wind and solar exposure although there are trends that storms come from the west.

12. Conclusion
Lichen are an important biomarker and very sensitive to pollution. Niwot Ridge road is frequented by snow mobiles in the winter that may be effecting these communities.
My results did not show significant difference between roadside and interior lichen growth, but the trend was consistent with my hypothesis that roadside would have less.
Future studies should take many more samples on various roads and closely examine the effect of branch aspect.

13. Citations
“What are lichens?” USDA Forest Service,
Jocelyn Campbell, Darwyn S Coxson. Canadian Journal of Botany, 2001, 79: , / b
Jarle W. Bjerke, Dylan Gwynn-Jones, Terry V. Callaghan, Effects of enhanced UV-B radiation in the field on the concentration of phenolics and chlorophyll fluorescence in two boreal and arctic– alpine lichens, Environmental and Experimental Botany, Volume 53, Issue 2, April 2005, Pages , ISSN ,
Brown, D. H., and R. P. Beckett. "Uptake and Effect of Cations on Lichen Metabolism* | The Lichenologist." The Lichenologists 16.2 (1984): n. pag. Cambridge Core. Cambridge University Press, 01 Mar Web. 11 Apr DOI:
Garty, J. "Biomonitoring Atmospheric Heavy Metals with Lichens: Theory and Application." Critical Reviews in Plant Sciences 20.4 (2001): n. pag. Critical Reviews in Plant Sciences. 24 June Web. 11 Apr

14. Appendix

15. Proportion of Sampled Branches with Lichen
To further explore the difference in lichen roadside and in the interior forest, I analyzed the difference in proportions of total branches with lichen out of the 30 branches sampled per treatment.
Roadside, 10 of 30 branches had lichen on them and the interior sites’ trees had 16 of 30 branches with lichen. The p-value was the same at and the difference is not statistically significant.
Results