COS 74-4
The effects of a decade of altered temperature on soil fungal communities
In the American Southwest, climate change is expected to increase the intensity of drought and elevate temperature. Monitoring and analyzing ecosystem responses to long-term temperature increases is imperative to climate change research. Specifically, soil fungal responses to warming are poorly characterized in recent literature. Sufficient knowledge of fungal community responses to warming is necessary to complement current climate change and soil science research. In Flagstaff, Arizona a natural elevation gradient exists where conditions associated with climate change in the Southwest can be simulated. The C. Hart Merriam Elevation Gradient was utilized by transplanting intact grassland communities down gradient to warmer and thus drier ecosystems. Intact micro-ecosystems were either transplanted down gradient to its neighboring lifezone or in their parent ecosystem. Soil was contained in sunken plastic cylinders 30 cm in diameter by 40cm deep for each control and experimental site across the Mixed Conifer, Ponderosa Pine, Pinyon-Juniper, Desert Grassland, and Great Basin Desert ecosystems. Samples were collected ten years after transplantation. We used Quantitative Polymerase Chain Reaction (qPCR) and 454 Pyrosequencing with ITS1F and ITS2 ribosomal DNA primers to determine fungal abundance and community composition in response to warming. Pyrosequencing data was processed using the QIIME software package with ordinations created in PCoRD, Primer, and JMP statistic programs.
Results/Conclusions
Statistical analyses of fungal communities from ambient and warmed treatments indicate a significant interaction between warming and soil fungal community composition. All samples show statistically different fungal taxa in ambient and warmed soil fungal communities. Warmed ecosystems are statistically different from both parent and transplant ecosystems. These differences are most pronounced in the mesic ecosystems such as the Mixed Conifer and Ponderosa Pine ecosystems. The arid ecosystems, Pinyon-Juniper and Desert Grassland, display community differences, but not as pronounced as the mesic ecotones. We found that beta diversity changed with warming, but there was no significant influence of warming on alpha diversity. Additionally, each warmed ecosystem has a different occurrence of indicator species than their parent ecosystem. Fungal abundance did not significantly change between warmed and ambient ecosystems with the exception of warmed Ponderosa Pine soil. Warming caused a 100% increase in fungal abundance compared to the control community. Complementary research on plant community response indicates that warming changes plant community composition, richness, and evenness. A shift in plant community and fungal community in response to long-term warming has important and interesting implications for ecosystem processes in the Southwest.