Timling, Ina , Taylor, Lee , Walker, Donald .
Shifts of ectomycorrhizal fungal diversity along a bioclimatic gradient from the low to the high Arctic.
Fungi are key components of terrestrial ecosystems that drive mineral and energy cycling, and influence the occurrence of other organisms. The two most prominent functional groups are saprophytic decomposer and mycorrhizal fungi. Ectomycorrhizal fungi form symbioses with a variety of plants. Nonetheless, their abundance, diversity, and functions in the arctic tundra and their potential responses to climate change are poorly understood.
The goal of our project is to test whether ectomycorrhizal fungal communities shift in tandem with changes in plant communities and abiotic factors along a bioclimatic gradient from the low to the high Arctic. We collected roots from Dryas integrifolia and Salix arctica at seven sites along this gradient. DNAs were extracted from ectomycorrhizal morphotypes and the ITS region was sequenced.
We find that the ectomycorrhizal communities are dominated by a few common families (Thelephoraceae, Cortinariaceae, Tricholomataceae, Sebacinaceae, Pyronemataceae). A total of 165 OTUs were observed, with 127 OTUs belonging to the Basidiomycota and 38 to the Ascomycota.
The highest diversity was observed in the intermediate bioclimatic subzone. While both host plants show similar species richness along the gradient (118 OTUs on Dryas integrifolia, 131 OTUs on Salix arctica), they harbor distinctive fungal communities. Neighboring islands/ locations had the greatest similarity in fungal species composition. Most fungal taxa we encountered are also found in other regions of the Arctic as well as in temperate climates from a variety of different hosts. Some of the sequence types do not fall within known species groups, and may represent novel species. Abiotic factors correlated with fungal community composition include freezing degree days of air and soil, minimum temperature of air and soil, latitude, and soil moisture.
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1 - University of Alaska Fairbanks, Department of Biology and Wildlife, 211 Irving 1, Fairbanks, AK, 99775, USA
2 - University of Alaska Fairbanks, Institute of Arctic Biology, 311 Irving 1, Fairbanks, AK, 99775, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Cottonwood C/Snowbird Center
Date: Wednesday, July 29th, 2009
Time: 4:30 PM