The impact of fire and elephants on a mixed woodland in Liwonde National Park, Malawi: the results of a thirty-seven year study

Cornell Owen Dudley

Abstract


Shortly after Liwonde National Park was gazetted in 1973, the influence of fire and elephant foraging was expected to be the priority management consideration. A number of permanent woodland plots were established, including a 200 × 10 m belt transect in open mixed woodland. All woody plants >1.5 m high were individually followed individually over the 37-year study. Declines in canopy tree numbers (58%) and species losses (7 of 19) were gradual throughout the period. Mean physical characteristics such as height, stem basal area and canopy cover were either stable (height) or increased slowly through the first three sample periods, with notable gains in the last 16 years. In spite of the substantial decline in the number of individuals, growth of the surviving larger trees compensated for these losses until 2014. During the first 21 years, upper canopy tree loss through fire remained stable at 0.8 trees/year. Over the last 16 years mean annual fire losses was 1.1 trees/year with five trees lost in 2015. Elephant damage through ‘pushovers’ remained very low at 0.3 trees/year up to 1999. With increasing elephant numbers this increased to 1.1 trees/year, reaching 5.0 trees/year in 2015. All pushovers were ultimately killed by fire. Elephant foraging had a strong synergistic effect on fire mortality. Tree species remain in the shrub layer as rootstock or fire suffrutices. With continued burning to ground level each year these will gradually die out. Damage and mortality at this intensity will eventually reduce this woodland to tall dense grassland with scattered large trees.

Keywords


African elephant, fire, woodland dynamics

Full Text:

PDF


Powered by PostgreSQL Hosted by ibiblio Creative Commons License