Large shifts in regional rainfall patterns are expected to occur as a consequence of rising global temperatures. Because rainfall is often a primary controller of ecological communities and ecosystem function, new rainfall patterns can have far-reaching effects. In California, models predict either more rain during the current winter rainy season or a longer rainy season that extends into the normally dry summer. Both intensified and extended rainy seasons are likely to affect plants and soils in ways that may be mediated by soil fungi. Fungi are typically the dominant microorganism in temperate soils. They also have key roles in nutrient recycling, soil carbon storage, and soil organic matter formation; though all of these functions are sensitive to soil wetness. The objectives of this proposal are to determine how intensified vs. extended rainfall will affect (1) soil fungal community composition and function, and (2) carbon pools and fluxes mediated by soil fungi. A combination of molecular methods and culturing will be used to identify fungi; stable isotopes will be used to trace the flow of carbon through fungi into the ecosystem.
With only 3% of soil fungi identified, the proposed work will improve our knowledge of soil fungi and their function. By examining the mechanistic link between altered rainfall patterns, soil fungal communities, and soil carbon cycling, this research will also provide a basis for predicting the future capacity of fungi in soil carbon storage. Understanding the consequences of impending environmental change will help us to better prepare for that change and will contribute to the development of ways to ameliorate any negative impacts.
