Influence of Macchia eradication techniques on botanical composition of grasses in the Dohne Sourveld of the Amatole Mountains.

Abstract

Grass communities identified through association-analysis were used for determining the effects of several methods for eradicating and controlling macchia. Follow-up burns at three frequencies applied over a ten-year period to control macchia were found to have masked most differences in species composition of the grass sward which may have arisen as a result of eradication treatments of burning, spraying and cutting. However, Elyonurus argenteus Nees and Harpechloa falx (L.) Kuntze were absent only from stumped plots. Themeda triandra Forsk. and Apochaetae hispida (L.f.) Phipps survived in a vegetative stae in unburned, control plots for about 20 years in spite of competition from a dense, bushy growth of macchia (Cliffortia paucistaminea H. Weim., C. linearifolia Eckl. & Zeyh. and Erica brownleeae Bolus). Themeda triandra was best adapted to withstand frequent burning while Heteropogon contortus (L.) Beauv. ex Roem. & Shult. was suppressed by this treatment. Certain other grasses may have survived entirely below the soil, and without evidence of aerial portions, in moribund veld. Basal cover was used for recommendations on veld burning management, whether for purposes of water production or for grazing.

Keywords: amatole mountains; apochaetae hispida; association analysis; basal cover; botanical composition; burning; cliffortia linearifolia; cliffortia paucistaminea; competition; control; cutting; dohne sourveld; elyonurus argenteus; eradication; erica brownleeae; grass sward; grasses; grazing; gxulu kop; harpechloa falx; heteropogon contortus; keiskammahoek; macchia; management; method; production; south africa; species composition; techniques; themeda triandra; treatments; veld; veld burning