PARENT SESSION
Contributed Oral Session 7: Disturbance Ecology: Fire; Litter; Animal response
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 518 A, Level 5, Palais des congrès de Montréal

Effects of fire on savanna vegetation characteristics in Kruger National Park, South Africa: Development of a generalized canopy cover model.

Benning, Tracy^*,1, Saah, David¹, ¹ Department of Environmental Science, San Francisco, CA, USA

ABSTRACT- A variety of factors contribute to the spatial heterogeneity of savanna landscapes. Some major agents of spatial heterogeneity in southern African savannas include microclimatic gradients, geomorphic processes, flooding regimes, fire history, and parent material. The objective of this analysis was to examine how vegetation characteristics were affected by the temporal and spatial patterns of fire in Kruger National Park, South Africa. In particular, we assessed the contribution of fire parameters to the overall spatial heterogeneity of vegetation canopy cover in this system by documenting the temporal and spatial distribution of fire and relating the patterns to precipitation, multi-spectral indices, and biomass normalized by geologic substrate. The fire analysis correlated individual fires to precipitation records and summarized fire frequency over 25 years. The temporal multi-spectral response to fire was analyzed using Normalized Difference Vegetation Index (NDVI) and Tasseled Cap vegetation indices for the fall and spring seasons starting in 2000 and ending in 2004. The effect of fire on biomass was investigated using historical fire data combined with veld condition assessment (VCA) biomass data over a 15 year time period (1989 through 2004). The results from these analyses were then integrated to create a generalized canopy cover data set that incorporated potential influences of fire frequency, geology, and seasonality. A generalized canopy cover model was developed that incorporated the most significant drivers of spatial variation in canopy cover. Results from this work indicate that the fire was not an important variable controlling canopy cover across this landscape.

Key words: savanna, fire, spatial heterogeneity, canopy cover