Dr Christie Klimas
Both anthropogenic change and the spread of invasive species have led to changes in urban and forest tree diversity. Oak rust, acute oak decline, and emerald ash borer have all had a detrimental effect on tree species in the Chicagoland area. Quercus species are well known habitats for lichen species including Physcia millegrana, Physcia stellaris, Punctelia rudecta, Flavoparmelia caperata, Xanthomendosa, and Candeleria concolor. Due to the decrease in the traditional Quercus habitats for lichen and the increase in nonnative and nontraditional tree species being introduced, particularly in cities, this study aimed to compare the number and diversity of lichen species between trees outside of Chicago, forest locations, and trees inside the city, city location, to determine if lichen would be observed on new host tree species which we hypothesized that in the absence of Quercus species lichens would be observed on new host tree species. Lichens were surveyed along transects in urban and forest preserves, with tree species and geographic location recorded. A generalized linear model was plotted. It was found that P. milegrana was consistently found on oaks and honey locusts in forest preserves, while P. stellaris were found on forest floors. P. rudecta and F. caperata were found along isolated honey locusts in forest preserves and urban areas while Xanthomendosa and C. concolor were found throughout both locations and tree species. In urban areas, P. milegrana was found to live on maples in absence of preference species of oaks, however it was found mostly on Quercus species. P. rudecta and F. caperata were found on honey locusts both in city and in forest preserves. P-scores less than 0.05 indicated a statistical difference between forest and city locations and between Quercus and non-Quercus species, with non-Quercus species hosting significantly less lichens than Quercus species. While lichens were present on nontraditional tree species, the number of lichens on nontraditional were on average less than lichen species observed on the traditional tree species, Quercus.
"An Analysis of Lichen Presence on Quercus and non-Quercus in Chicagoland Area,"
DePaul Discoveries: Volume 12, Article 5.
Available at: https://via.library.depaul.edu/depaul-disc/vol12/iss1/5