Spatial variation of fire behavior on simulated grassland mosaics.
Kerby, Jay*,1, Engle, David1, Fuhlendorf, Samual1, 1 Oklahoma State University, Stillwater, OK, USA
ABSTRACT- The fire-grazing interaction is a spatially controlled process in many grasslands. North American tallgrass prairie evolved under pressure of fire and grazing which interact to create a shifting mosaic of disturbance across landscapes. Spatial variability of biomass is altered by interaction of fire and grazing, thus creating a heterogeneous distribution of fuel patches in the event of natural or prescribed fire. The size of fuel patches can vary depending on previous disturbance history (i.e. previous fire sizes) and recent disturbance processes (i.e. spatially variable grazing intensity causing small and large fuel patches). We evaluate the influence of fuel patch size on fire behavior across a simulated tallgrass prairie landscape. We compare fire behavior on landscapes with four sizes of fuel patches (2.25 ha, 9 ha, 36 ha, and 144 ha) using FARSITE, a fire-growth simulation model. We measured fire area, fire perimeter, fire intensity, fire type and fire shape complexity. All response variables responded to fuel patch size, illustrating the importance of fuel patch size to fire behavior. These results suggest that scale of fuel heterogeneity created by patterns of landscape disturbance may have an important ecological role in the feedback mechanisms of a fire-grazing model on grasslands. The results also suggest that scale of fuel heterogeneity plays a role in managing wildland fire.
Key words: fire-grazing interaction, fire modeling, tallgrass prairie
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