Honors Theses

Date of Award

Spring 5-8-2020

Document Type

Undergraduate Thesis

Department

Biology

First Advisor

Jason Hoeksema

Relational Format

Dissertation/Thesis

Abstract

Biological invasions can cause significant changes to the environment in which they occur. One of the main changes that is caused is how invasive species can disrupt mutualisms between native species in ecosystems. The mutualism between mycorrhizal fungi and plants is one of the most important mutualisms that a plant forms. This mutualism is very important because it is the source of many nutrients that the plant needs. This study took place in a Scots pine (Pinus sylvestris) plantation in northeastern Poland, and aimed to determine the effects of plant and beetle invaders on ectomycorrhizal (ECM) fungi and roots associated with the pine. Soil was collected from under Scots pine trees at sites that were invaded by beetles (Phaenops cyanea), Quercus rubra, Robinia pseudoacacia, Q. rubra and R. pseudoacacia together, and control (uninvaded) sites. In the lab, pine root length and ECM colonization intensity were quantified, and ECM fungi were identified using Sanger sequencing of colonized pine root tips. Twenty-eight different ECM fungal OTUs were found, but none of the individual OTUs, genera, or families were frequent enough to perform statistical tests of effects of site types. When focusing on the OTUs, Laccaria_1 was the most abundant and Cortinarius_1 was the most frequent. When focusing on each genus, Laccaria was the most abundant and Tomentella, Russula, and Lactarius were the most frequent. When focusing on each family, Russulacae was the most abundant and Thelephoraceae was the most frequent being found in four different samples. The presence of beetles did not affect any of the root or ECM colonization variables. When ignoring the beetles, instead only focusing on whether the site was invaded by R. pseudoacacia, Q. rubra, or both, total pine root length was dramatically reduced in sites that contained both plant invaders and there was a similar trend towards reduction of total ECM colonization. Although the exact mechanism for how the invaders affect the native plants is unknown, it is possible that the invaders affect the native plant in many different ways that could lead to an overall change in reduced soil resources, reduced pine growth and even native pine tree death.

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Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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