Landscape heterogeneity and fire behavior: scale-dependent feedback between fire and grazing processes |
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Authors: | Jay D Kerby Samuel D Fuhlendorf David M Engle |
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Institution: | (1) Department of Plant and Soil Sciences, Oklahoma State University, 368 Agriculture Hall, Stillwater, OK 74078, USA;(2) Department of Natural Resource Ecology and Management, Iowa State University, Ames, IA, USA |
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Abstract: | Fire and grazing are ecological processes that frequently interact to modify landscape patterns of vegetation. There is empirical
and theoretical evidence that response of herbivores to heterogeneity is scale-dependent however the relationship between
fire and scale of heterogeneity is not well defined. We examined the relationship between fire behavior and spatial scale
(i.e., patch grain) of fuel heterogeneity. We created four heterogeneous landscapes modeled after those created by a fire–grazing
interaction that differed in grain size of fuel patches. Fire spread was simulated through each model landscape from 80 independent,
randomly located ignition points. Burn area, burn shape complexity and the proportion of area burnt by different fire types
(headfire, backfire and flankfire) were all affected by the grain of fuel patch. The area fires burned in heterogeneous landscapes
interacted with the fuel load present in the patch where ignition occurred. Burn complexity was greater in landscapes with
small patch grain than in landscapes with large patch grain. The proportion of each fire type (backfire, flankfire and headfire)
was similar among all landscapes regardless of patch grain but the variance of burned area within each of the three fire types
differed among treatments of patch grain. Our landscape fire simulation supports the supposition that feedbacks between landscape
patterns and ecological processes are scale-dependent, in this case spatial scale of fuel loading altering fire spread through
the landscape. |
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Keywords: | Burning Herbivory Landscape pattern Modeling Shifting mosaics Simulation Vegetation biomass |
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