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The Arboretum and Lichen Diversity: Study Results

lichen research

Troy McMullin (left) and Jose Maloles at the site where they found a new-to-science species of lichen in The Arboretum. Photo by Chris Earley.


For the last 6 years, Troy McMullin has been surveying our site for lichens. During his first visit, he found 25 species. By the time he had finished his 49th visit, he, along with help from his colleague Jose Maloles, had assembled a list of 104 lichen and allied fungus species, all found within our boundaries. And one of these lichens was new to science! Other discoveries include a species new to Canada and three that are the second or third records for Ontario. Nine of the species found are rare in Ontario with a ranking of S1 (critically imperilled), S2 (imperilled) or S3 (vulnerable).


So what makes The Arboretum so lichen-friendly? It appears that our diversity of habitats (which includes old-growth forests) and various substrates (such as calcareous rock, granitic rock and different types of tree bark) provide homes for our many lichen species. Furthermore, our site seems to be a refuge from city effects. Lichens are very sensitive to pollution and their diversity in cityscapes is low. The Arboretum contains many species of lichens that were not found anywhere else within the city limits.


The results of Troy's study show that urban parks and conservation areas can provide important lichen habitat. It is hoped that The Arboretum can be used as a baseline example for other cities to study local lichen diversity and use the results to protect and enhance their urban natural areas.


To see the full paper, McMullin, R.T., J.R. Maloles, C. Earley and S.G. Newmaster. "The Arboretum: An urban refuge for lichen diversity." North American Fungi 9(5):1-16., please click here. For more information on Arboretum lichens and Troy's studies, please click here.


Arboretum Reflection Read More

Students collect Blue Ash Seeds Read More

Arboretum Tree Ice Damage Report Read More

Biodiversity Sheets for Nature Awareness Read more

Landscape Student Helps Put Runners on the Right Track Read more

Enjoying Mother Nature's Benefits Read more


Click here to read more past articles on The Arboretum.

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Master Plan



Operational Plan

Arboretum Beginning

The Arboretum at the University of Guelph is somewhat modeled after the Arnold Arboretum of Harvard University which is 100 years older.

Plantings started in 1971 and are now maturing to produce a beautiful landscape, within which The Arboretum continues to develop specialized gardens, botanical collections, and gene conservation programs.

Labels are maintained at the base of all woody plants in the collections that are listed on The Arboretum map.

University of Guelph Arboretum
College Ave East
Guelph, Ontario, N1G 2W1

ext. 52113


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