COS 133-6
Community structure of arbuscular mycorrhizal fungi along an undisturbed high elevation gradient

Friday, August 15, 2014: 9:50 AM
Regency Blrm C, Hyatt Regency Hotel
Cameron Egan, Department of Biology, University of British Columbia Okanagan, Kelowna, BC, Canada
Ragan M. Callaway, Division of Biological Sciences and the Institute on Ecosystems, The University of Montana, Missoula, MT
Jason Pither, Biology, University of British Columbia, Okanagan Campus, Kelowna, BC, Canada
Miranda M. Hart, Biology, University of British Columbia - Okanagan, Kelowna, Canada
John Klironomos, Department of Biology, University of British Columbia, Kelowna, BC, Canada

Despite the importance of arbuscular mycorrhizal (AM) fungi within terrestrial ecosystems, we know little about how natural AM fungal communities are structured. To date the majority of studies examining AM fungal community structure and functioning have been restricted to a single environment type. Relatively few studies have assessed the relationship between plants and AM fungi over large scale environmental gradients. Elevation gradients have been studied for centuries to observe patterns of plant and animal diversity, and more recently microorganisms. Microorganisms have been shown to not follow the same patterns as plant and animal diversity along the same elevations indicating that the processes for shaping the communities is not the same as plants. Using 454 pyrosequencing to characterize AM fungal communities in soil, samples were taken along a high alpine elevation gradient to determine the effects of elevation on AM fungal community assembly. This research examines phylogenetic and taxonomic patterns of undisturbed AM fungal communities in order to gain insights into how AM fungal communities are naturally structured and comments on how that structuring can affect ecosystem functioning.  


Characterizing AM fungal communities along an untouched high alpine gradient this research contributes to a deeper understanding of how naturally occurring communities are assembled. Elevation has a significant influence on AM fungal diversity. Both AM fungal species richness and phylogenetic diversity were found to decrease as elevation increases, with the highest elevation being significantly lower in both phylogenetic diversity and species richness compared with the lowest elevation sampled. Phylogenetic composition was compared among communities within elevations and along the elevation gradient. High elevation communities were found to be significantly more heterogeneous in composition relative to both mid and low elevation communities. This suggests that AM fungi occur in phylogenetic clusters at high elevations and become more evenly mixed at lower elevations. Cosmopolitan AM fungi were present at all elevations, suggesting that certain AM fungal taxa are habitat and host generalists while other taxa are filtered by either abiotic conditions or plant host availability. Using phylogenetic approaches provided insights into the processes determining the diversity patterns of AM fungi along elevation. Filtering due to either abiotic conditions or host availability may be the drivers of decreased species richness and phylogenetic diversity with increasing elevation.