Collaborative Research: Fire-fungal-plant feedbacks in pyrogenic ecosystems

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Unlike most natural disturbances, such as hurricanes or floods, characteristics and effects of fires depend on the plants present and the fuels they produce, both live flammable leaves and dead tissues that are released into the surrounding environment. Plants that live where fire occurs frequently are often capable of surviving fires. Some of these plants produce fuels that change the likelihood and characteristics of future fires, producing conditions favorable to them and/or their offspring. Soil organisms also affect plant fuels, and some are capable of surviving fires. They represent an important but unrecognized driver capable of altering fuels and future fires, especially in habitats with frequent fires. Soil fungi are a key example of such soil organisms, directly affecting fuel loads by decomposing dead plant tissues and indirectly affecting fuel production through their effects on plant growth. Because fungi differ in fire susceptibility, repeated fires may shape the fungi present, altering direct and indirect effects on fuels (and thus future fires). Knowledge of these fungal effects is important for managing natural fire-frequented habitats such as savannas and grasslands and forecasting the characteristics (such as the likelihood and intensity) of future fires in most terrestrial habitats. This research examines how changes in fires (severity, frequency, suppression) influence fungi and their effects on new fuels, both directly through fuel breakdown and indirectly through plants, then models how these differences may affect future fires. This research will also develop two educational modules on fire, fungi and plants: 1) undergraduate students will test different fire traits of cultured fungi and 2) K-5 classrooms will use inquiry-based learning kits that are developed on fire, fungi and plants, and that directly address next generation science standards. The research will be conducted in pine savannas, highly diverse and threatened southeastern habitats dependent on frequent fire. Initial research showed that fire alters soil fungi and results in 40% slower decomposition by microbes of dead plant leaves newly deposited on the ground. Slower decomposition causes fuels to accumulate more quickly in the environment, increasing chances and intensities of future fires. This research uses large-scale field experiments with fire, next generation DNA sequencing, and computer modeling to determine how soil microbes like fungi respond to fire, and if they play an unrecognized role by influencing likelihoods and characteristics of future fires. Because these effects are tested over a spectrum of fire severities, the model based on experimental results can be used in other pyrogenic habitats and can be used to forecast likelihoods and effects of future fires.