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Adam Pellegrini
Stanford University
"Shifting Fire Regimes and Their Compounding Impact on Ecosystem Biogeochemistry"
Abstract: Each year, fires burn ~570 million hectares, producing carbon losses that are equivalent to ~20% of the emissions from anthropogenic fossil fuel consumption. After fire, the recovery of plants can offset these losses by sequestering carbon during regrowth. Long-term shifts in fire regimes may change the balance between losses and recovery, but multiple factors restrict our ability to forecast such changes. Here, I will present data that address the uncertainty in how soils respond to long-term changes in fire regimes, the potential link between soil and plant responses, and how plant traits may structure these fire-plant-soil interactions. My results demonstrate that more frequent burning leads to decadal alterations in soil carbon and nutrients, and that effects vary predictably based on ecosystem type, the amount of time fire regimes have been altered, and the physicochemical properties of elements. Further data illustrate the potential for fire-nutrient interactions to influence the ability of ecosystems to recover by regulating plant productivity and the trait composition of the plant community. I will conclude by discussing the utility of certain plant traits in predicting the resilience of ecosystems to fire in modelling contexts.