Fire in a semi-arid African savanna: Pastoral management practices and ecological effects

Fire in African savannas is part of a complex system of landscape-level management by local people. Yet despite anthropogenic fires accounting for more than 70 percent of the annual fires in African savannas, research on traditional fire practices is limited and the roles that anthropogenic fires play in vegetation dynamics remain poorly understood. A Maasai village in northern Tanzania was chosen to examine pastoral fire management practices and their ecological effects. Chapter 1 investigates recent changes in resource management associated with charcoal production by women. Population growth, drought, social and economic marginalization, and a lack of other marketable resources are leading to increasing rates of extraction. While demand for fuelwood is unlikely to deplete forest cover on a large scale, localized scarcities and degradation of savanna vegetation may occur.;Chapter 3 investigates the composition of savanna vegetation and the effects of fire frequency on plant community structure and composition using burn sites of varying ages. Significant differences between burned and unburned plots were identified at all sites. In the absence of frequent fires, accumulation of standing plant biomass of low nutritive value and a shift in dominance towards increased shrub cover occurred without an overall shift in species composition. Changes in fire management, particularly those leading to a reduction in fire frequency caused by land use change, fire prevention activities, and active fire suppression, could lead to significant structural changes and succession toward more fire-sensitive and shade-tolerant overstory species.;Chapter 2 examines historic and contemporary uses of fire as a land management tool and explores potential impacts of changing fire management and suppression on savanna vegetation. Historically, a progression of small fires was set throughout the dry season to create a fragmented burn pattern and to prevent large, catastrophic late-season fires. Currently there is little active vegetation management using fire due to federal fire suppression policies, unpredictable rainfall patterns, increasing populations, and a subsequent increase in the number of catastrophic accidental fires. Substantial modifications to historical fire regimes could have cascading consequences for savanna health by increasing late-season fuel loads and the occurrence of large, catastrophic fires.