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dc.contributor.authorTimling, Ina
dc.descriptionDissertation (Ph.D.) University of Alaska Fairbanks, 2013
dc.description.abstractFungi are thought to be one of the most diverse groups of organisms in the Arctic. They drive mineral and energy cycles and influence the occurrence of other organisms as mutualists (mycorrhizae, endophytes, lichens), decomposers and pathogens. Nevertheless, information on fungal biodiversity and distribution patterns in relation to environments across the Arctic is still sparse. Molecular methods were used to examine the diversity and community structures of ectomycorrhizal fungi (EMF) associated with two principal arctic host plants, Salix aretica and Dryas integrifolia, as well as total soil fungal communities of adjacent disturbed and undisturbed areas of patterned-ground features across the five bioclimatic subzones (A-E) of the North American Arctic. Key findings include the following: (1) More diverse fungal communities had been observed than previously known. These communities encompass nearly all fungal phyla and included all fungal guilds. However, a few species-rich fungal families dominated these fungal communities. (2) Surprisingly, species richness did not decline with latitude. (3) The most abundant fungal taxa were widely distributed in and beyond the Arctic. Yet root (EMF) and soil fungal communities showed niche preferences in regard to bioclimatic subzones. Furthermore, disturbed and undisturbed patterned ground features harbored different soil fungal communities with the exception of the coldest subzone A. In contrast, EMF community composition was not affected by host plant identity. (4) Fungal communities in the warmest subzone E were distinct from the other arctic subzones and the majority of taxa matched fungi from the boreal forest. (5) Key drivers of fungal community and guild composition along the bioclimatic gradient included regional climate, p.H as well as vegetation composition and productivity across the subzones. At the local scale of patterned-ground features, fungal communities were correlated with vegetation composition and microclimate. With a warming climate, I would expect an enhanced colonization of patterned-ground features by vascular plants that would then affect fungal community structure not only at the species level, but also at the level of fungal guilds. In particular I would expect increases in fungi that are symbiotic with plants and a northward shift of both plant and fungal taxa.en_US
dc.description.tableofcontentsChapter 1. General introduction -- 1.1. References -- Chapter 2. Peeking through a frosty window : molecular insights into the ecology of Arctic soil fungi -- 2.1. Abstract -- 2.2. Introduction -- 2.3. Arctic soil : an extreme environment -- 2.4. Arctic soil fungal diversity -- 2.5. Fungal distribution patterns in Arctic soils -- 2.6. Responses of Arctic soil fungi to climate change -- 2.7. Adaptations of soil fungi to Arctic environments -- 2.8. Future challenges in Arctic soil mycology -- 2.9. Acknowledgements -- 2.10. References -- Chapter 3. Distribution and drivers of ectomycorrhizal fungal communities and across the North American Arctic -- 3.1. Abstract -- 3.2. Introduction -- 3.3. Material and methods -- 3.3.1. Study area -- 3.3.2. Sampling and processing -- 3.3.3. Molecular analysis -- 3.3.4. RFLP screening -- 3.3.5. Cloning and sequencing -- 3.3.6. Bioinformatics & statistical analysis -- 3.3.7. OTU clustering and alignment -- 3.3.8. Nomenclature -- 3.3.9. Ordination analysis -- 3.3.10 Diversity analysis -- 3.4. Results -- 3.4.1. EMF diversity in the Arctic -- 3.4.2. Patterns of EMF communities -- 3.4.3. Drivers of EMF community structure -- 3.5. Discussion -- 3.5.1. EMF diversity in the Arctic -- 3.5.2. Large scale EMF community patterns in the Arctic -- 3.5.3. Factors shaping EMF communities -- 3.6. Acknowledgements -- 3.7. References -- 3.8. Figures -- 3.9. Tables -- 3.10. Appendices -- 3.11. Supporting information -- Chapter 4. Rich and cold : diversity, distribution and drivers of fungi in patterned-ground ecosystems of the North American Arctic -- 4.1. Abstract -- 4.2. Introduction -- 4.3. Material and methods -- 4.3.1. Study areas and patterned ground features -- 4.3.2. Sampling and processing -- 4.3.3. Molecular analysis -- 4.3.4. Bioinformatics -- Sequence clean up -- Diversity analysis -- Ordination analysis -- Distribution of OTUs -- 4.4. Results -- 4.4.1. Fungal divesity in the Arctic -- 4.4.2. Species richness along the latitudinal gradient -- 4.4.3. Community structure across the bioclimatic subzones -- 4.4.4. Fungal community structure within patterned-ground complexes -- 4.4.5. Drivers of fungal community structure -- 4.5. Discussion -- 4.5.1. Fungal diversity in Arctic soils (general description) -- 4.5.2. Large-scale fungal community patterns in the Arctic -- Wide distribution of Arctic fungi -- Fungal species richness along latitudinal gradient -- Community structures and environmental drivers -- 4.6. Conclusions -- 4.7. Acknowledgements -- 4.8. References -- 4.9. Figures -- 4.10. Tables -- 4.11. Supporting information -- Chapter 5. Conclusions -- 5.1. Fungal diversity 5.2. Fungal distribution -- 5.3. Key drivers of fungal communities in the Arctic -- 5.4. Future work -- 5.5. A fungal 'outlook' -- 5.6. References.en_US
dc.titlePeeking through a frosty window: molecular insights into the communities of Arctic soil fungien_US
dc.identifier.departmentDepartment of Biology and Wildlifeen_US
dc.contributor.chairWalker, Donald A.
dc.contributor.chairTaylor, Donald L.
dc.contributor.committeeChapin, F. Stuart
dc.contributor.committeeLaursen, Gary A.
dc.contributor.committeeMulder, Christa P.

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