LE3 .A278 2023

2023

Walker, Allison

Acadia University

Bachelor of Science

Honours

Biology

Biology

Fungi have essential ecosystem roles; many decompose organic matter, while others form symbiotic relationships with plant roots. Ectomycorrhizal fungi provide nutrients and water to forest tree roots. Saprotrophic and lignicolous fungi are decomposers of organic matter and decaying wood. At Kejimkujik National Park, these three fungal guilds are found within stands of Eastern hemlock (Tsuga canadensis (L.) Carrière). Hemlock is a foundational tree species that provides a unique shaded habitat for many organisms. However, hemlock woolly adelgid (Adelges tsugae Annand.; HWA), an invasive insect, is causing severe hemlock decline in Eastern North America and has recently reached Nova Scotia. This may negatively affect other species within hemlock stands, including fungi. By drawing upon existing fungal collections from Kejimkujik at Acadia University’s E.C. Smith Herbarium, mushrooms collected in 2022 were compared with mushrooms collected between 1990-1995 from the same hemlock study plot (Plot A) to observe if fungal diversity had changed over the past 30 years. Between 2004-2007, over 1500 hectares of Eastern hemlock at Kejimkujik experienced light to severe defoliation by high densities of pale winged grey moth (Irodopsis ephyraria Wlk.; PWG) larvae. From August-November 2022, we made 57 field collections of hemlock-associated fungi from our study plot (i.e., after the PWG outbreak, and during the beginning of HWA infestation). Mushroom DNA barcode sequences we obtained were examined using phylogenetic techniques to determine fungal species’ identities. Fifty fungi were identified within our hemlock plot which contained HWA. We discovered 14 fungi not previously documented in our plot, and we re-documented 10 fungi present in the 1990-1995 herbarium collections. From our 2022 fungal collections, 86% of mushrooms collected were ectomycorrhizal, as compared to 82% in 1991 and 59% in 1995. The most common mushroom genus we collected was Cortinarius, which was the second-most collected genus in 1990. Our results suggest the hemlock fungal community did not decline due to the PWG outbreak or the current early HWA infestation. However, the fungal diversity in our plot did change within the last 30 years. The hemlock-associated fungi we documented could aid future studies in determining the effects of HWA on forest fungi.

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https://scholar.acadiau.ca/islandora/object/theses:3994