Vegetation change in the karoo

Abstract

Large scale and often radical change has taken place in Karoo vegetation over the past three centuries. This change can be equated with desertification and desertization processes. Change largely embodies the thinning out of the vegetation, decrease or destruction of perennial grass, and an increase and spreading of undesirable karoo bush and woody species. In many instances veld types have changed and the drier types extended into ‘the moister types. The overall vegetation change has been ordinated into five broadly overlapping phases. These are primary degradation, denudation, revegetation, secondary degradation and a desertified phase.

The main factor causing change is over‐exploitation by sheep. Seasonal fluctuations in climate enhance the instability of the vegetation.

Uittreksel

Grootskaalse en dikwels radikale veranderinge het in die Karoo plantegroei oor die afgelope drie eeue plaasgevind, Hierdie verandering kan gelyk gestel word met die prosesse van desertifikasie en desertisasie. Die verandering het die uitdunning van die plantegroei, afname en vernietiging van meerjarige gras en ‘n toename en verspreiding van ongewenste karoobossies en houtagtige spesies behels. In baie gevalle, het veldtipes verander en droër tipes in die vogtiger tipes uitgebrei. Die algemene plantegroeiverandering is in vyf bree oorvleuelende fases geordert. Dit is primêre aftakeling, ontbloting, herbedekking, sekundere aftakeling en ‘n verwoestynde fase.

Ooreksploitaste deur skape was die hoofoorsaak vir hierdie verandering. Seisoenale fluktuasies in die klimaat verhoog die instabiliteit van die plantegroei.