Short-term burning treatments and ecological interactions in the herb layer of False Thornveld of the Eastern Province.

Abstract

The effects of five years of controlled burning on total floristic composition and on some important species were investigated. The most marked effects of fire are shown in the reduction of numbers of species and the increase of grass relative to forbs. In addition, Themeda triandra is favoured by frequent burning but Cymbopogon plurinodis is favoured by longer intervals between fires. The seral status of these species in this ecosystem is discussed and the implications to pasture management pointed out. Species composition of the community is shown to be more strongly determined by habitat factors than by fire at present, and the forb component is the more sensitive indicator of these environmental gradients. The possible significance of the environmental gradients to long-term management plans is discussed.

Keywords: burning; composition; controlled burning; cymbopogon plurinodis; ecological interactions; effects; environmental gradient; false thornveld; fire; floristic composition; forbs; grass; grasses; habitat; habitat factors; intervals; management; management plan; pasture management; seral status; species composition; themeda triandra; treatments