Impact of elephants (LOXONDONTA AFRICANA L.) on baobab trees (ADANSONIA DIGITATA L.) in Man Pools National Park Zambezi Valley Region

Abstract

An assessment was made on elephant impact on a baobab population in Mana Pools National Park. Study sites were selected on the basis of their distance from the Zambezi River, a major source of perennial water in the park. The study also compared current levels (2005) of baobab density, damage and mortality to those obtained during 1980s in the northern part of Mana Pools National Park. Results showed that baobab density was significantly lower in 2005 than that obtained in the 1980s for northern Mana Pools National Park (Mann-Whitney, U=256, p=0.037). However there was no significant difference in basal area per km2 for the two study periods (Mann-Whitney, U=330, p=0.417995). The girth at breast height (gbh) size class distribution showed a shift in pattern from a J-inverse shape with more saplings in 1984 to a bell-shaped pattern with fewer plants in the smallest gbh size class in 1988 and 2005. Baobab mortality for the intervening period (1984-2005) was found to be lower (4.42%) than that experienced in the 1980s (7.3%). Results from this study showed that baobab density is significantly different between southern, central and northern Mana Pools National Park (Kruskal-Wallis ANOVA by ranks, H=7.61, df =2, p=0.022). The density increased with increased distance from the Zambezi River. Mean basal area per km2 and mean height was also significantly different between study sites. Chi-square test of independence showed a significant difference between damage categories for the three study sites and it was concluded that there is a relationship between damage and study sites. Elephant induced damage on baobab trees decreased with increasing distance from the Zambezi River. The study concluded that elephants are shaping the baobab structure in Mana Pools National Park. If baobab mortality in northern Mana Pools National Park continues at the present rate then only few old baobab trees will remain