PS 32-186 - Ecological and socioeconomic dimensions of anthropogenic fire in southern Africa: An interdisciplinary synthesis

Tuesday, August 9, 2011
Exhibit Hall 3, Austin Convention Center
Militsa J. Plavsic, Department of Environmental Studies, University of New England, Biddeford, ME, Michael Heinl, Institute of Ecology, University of Innsbruck, Innsbruck, Austria and Lin Cassidy, Okavango Research Institute, University of Botswana, Maun, Botswana

Fire is both a key process in the maintenance of species diversity and a natural resource management tool used by local stakeholders in southern Africa.  However, vestiges of the negative perception of fire by colonial powers survive in current natural resource management policies which outlaw most burning. Using the Okavango Delta in Botswana as a model system, we examined the recent fire history, ecological impacts of fire, and the socioeconomics of anthropogenic burning to form a holistic understanding of this complex issue.  The fire history of the southern Delta was reconstructed using a series of 98 satellite images from 1989-2003 inclusive.  Annual extent of fires, main fire season, maximum fire frequency and mean fire frequency related to flood frequency were calculated.  To examine the effects of fire on vertebrate populations, a capture-mark-recapture study of small mammals on grassland trapping grids used experimental burning.  To assess how fire affects the availability of natural resources for local stakeholders, a livelihoods assessment in the northern Delta was based on a quantitative household survey and informal theme-based interviews.


An analysis of vegetation data revealed that the Delta’s flora is highly adapted to regular fire-events.  The fire season indicated an anthropogenic rather than a natural fire regime for the Okavango Delta but the overall fire frequency is in the range of the fire frequency observed for other savanna or grassland systems in southern Africa.  Fire caused a complete turn-over of small mammals and led to a decrease in carrying capacity but not individual fitness. Most populations had recovered by the end of the first post-fire rainy season.  The current fire regime is likely not a threat to small mammals at the population level, although further increases in fire frequencies, coupled with predicted climate change, could threaten some species.  A quarter of all households experienced fire in a typical year; however fire overall had a positive effect on the availability of wetland resources. The limited conflict that occurred was associated with poor timing and the lack of warning that a fire was to be set. This in turn was due to the secretiveness that the illegality of the practice induced.  Our results suggest that the official, unenforced ban on burning is not needed; instead a patch mosaic of burning, both natural and anthropogenic, is suggested.  Decentralized fire management, where coordination again occurs at the village level, is recommended.


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