Invasive Species Compendium

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Abstract

The proposed colonisation sequence of woody species in the Sourish Mixed Bushveld of the Limpopo province, South Africa.

Abstract

The long-term establishment sequence of the woody component of the Sourish Mixed Bushveld of the Limpopo province was studied and documented. Vegetation surveys were conducted at a protected site at the Towoomba Agricultural Development Centre during 1977 and 2000. Over the 23-year period, bush density at the site increased by 33%. Changes in the woody component indicated a shift from an acacia-dominated site to one dominated by broadleaved tree species. Early colonisers included mostly Acacia species (A. karroo, A. robusta, A. nilotica, A. gerrardii, A. tortilis, A. caffra, A. habeclada and A. mellifera), Dichrostachys cinerea and a few broadleaved species (Ximenia caffra, Dombeya rotundifolia and Searsia spp.). Intermediate colonisers included various shrubs (Diospyros lycioides, the Maytenus/Gymnosporia species group, Euclea species, Carissa bispinosa and Grewia spp.), a limited number of tree species (Pappea capensis, Boscia albitrunca and Ziziphus mucronata) and only two legumes (A. robusta and Peltophorum africanum). Late colonisers included only broadleaved shrubs and Waterberg Mountain Sourveld tree species (Grewia flavescens, Tarchonanthus camphoratus, Berchemia zeyheri, Cassine transvaalensis, Schotia brachypetala, Ximenia caffra, Heteropyxis natalensis, Terminalia sericea, Vangueria infausta and Searsia lancea). The leguminous and broadleaved components appeared to have distinct establishment sequences. Acacia spp. appeared to facilitate the early invasion of broadleaved woody species.