Monday, 17 November 2003: 2:30 PM
Consequences and correlates of fire in wetlands
Under what conditions does fire in wetland environments consume substantial organic soil and generate substantial smoke? Does this depend on the wetland type? On whether the burn is prescribed or a wildfire? On hydrological conditions or drought conditions at the time of the burn? We have studied these questions in a large multiyear study at The Nature Conservancy's Disney Wilderness Preserve in Kissimmee, FL. We used data on depth of the organic soil collected at a large number of study sites in 1996 and again in 2002, together with our records on fires throughout the Preserve. Due to the severe multiyear drought in Florida during this period, most sites lost organic soil to oxidation, but the amount of loss depended on whether sites were burned and varied among plant community types. One wetland type, bayheads (usually
associated with deep organic deposits, and rarely burned), showed a simple response: burning nearly always increased the soil loss, and greatly decreased the variance in soil loss. In most other wetlands, soil loss depended on conditions under which the burn occurred; in these cases, burning increased the variance in soil loss. These results,
together with our results on how burning affected wetland vegetation, may prove useful in developing guidelines on how to manage fire in wetlands and on the ecological consequences of these fires.
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