Electronic Theses and Dissertations

Title

The Fungal Connection: Characterizing the Ectomycorrhizal Community and Belowground Response to Restoration Treatments in Northern Mississippi.

Date of Award

2010

Document Type

Dissertation

Degree Name

M.S. in Biological Science

First Advisor

Jason D. Hoeksema

Second Advisor

Stephen J. Brewer

Third Advisor

Tamar Goulet

Abstract

Ectomycorrhizal (ECM) fungi are symbionts on the roots of woody plant species throughout the world. These fungi provide plants with nutrients and are important drivers of ecosystem processes. ECM fungi vary in their effect on host plants and host-specificity, making them important considerations in restoration projects seeking to restore target tree species. Restoration strategies such as burning and thinning may have strong impacts on ECM fungi, and given the that ECM are important in structuring aboveground communities and maintaining certain dominant plant taxa, knowledge of ECM fungal response is needed to ensure restoration efforts succeed. Using molecular methods, this research aimed to identify the ECM fungal community in a restoration project in northern Mississippi, comparing the belowground fungal community on plant roots between replicated control and treatment plots. We also measured abiotic factors that may structure the ECM fungal community, including litter depth, canopy openness, burn regimen, and soil compaction. Results indicate that the ECM fungal community is very diverse with 175 operational taxon units recovered from sequence data, 106 OTUs only found once. The fungal species had high site fidelity, with site being the factor explaining the most variation in community structure. Taxa in the family Russulaceae represented the most abundant fungi found on roots, followed by Thelephoraceae. The abiotic factors measured accounted for only 10% of the variation in community structure, indicating that other unmeasured variables may account for the remaining variation in ECM community distribution. Spatial autocorrelation was found at one of the six plots, indicating similar ECM fungal species composition at scales greater than in the other 5 sites. This plot also had the greatest canopy openness and oak regeneration, suggesting that this greater spatial autocorrelation could be related to oak seedling facilitation. The restoration treatments did not have a strong impact on fungal community structure except in the Tallahatchie plots, where there was a strong difference between treatment and control plots. This study was the first assessment of belowground ECM fungal diversity in Mississippi, and will serve as a starting point for further investigation into shifts in the fungal community as a result of restoration.

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