Ecological profiles of potential bush encroacher species in the Manyeleti Game Reserve

Abstract

The habitat preferences of twelve potential bush encroacher species in the Manyeleti Game Reserve, situated in the Arid Low-veld veld type in the eastern Transvaal, were investigated. These species have wide distribution patterns and owing to their presence in many sample plots, high frequencies were recorded in almost all classes of various habitat variables. Application of the Ecological Profiles Technique therefore resulted in disappointing results, as habitat preferences could not be established. The technique was modified to process quantitative density data (individuals per hectare) and the resulting profiles were expressed in terms of relative mean density per habitat class. The results were significant and habitat preferences were positively identified. Grouping of species with similar profiles lead to the identification of the following five indicator groups: Terminalia sericea, Combretum zeyheri, C. apiculatum and Acacia exuvialis with preference to sandy, acid, leached, non-sodic soils with low conductivity. Pterocarpus rotundifolius with preference to clayey, acid, medium leached, non-sodic soils with low conductivity. Acacia gerrardii, A. nigrescens and Albizia harveyi with preference to clayey, alkaline, non-leached, sodic soils with high conductivity. Dichrostachys cinerea, Dalbergia melanoxylon and Ormocarpum trichocarpum with preference to very clayey, alkaline, moderately leached, slightly sodic soils with medium conductivity. Maytenus senegalensis with preference to sandy, neutral (pH), moderately leached soils with medium conductivity.