Rate and pattern of bush encroachment in Eastern Cape savanna and grassland

Abstract

The rate and pattern of bush encroachment in the grasslands and savannas of the Kei Road-Komga region of the Eastern Cape were quantified by analysis of nine sets of aerial photographs taken between 1937 and 1986. Woody cover increased from 17% to 35% over this period. with most of the increase occurring after 1963 and possibly related to well above-average rainfall. Bush encroachment involved the invasion of grassland and the thickening of savanna. Valleys were always two to three times more wooded than slopes or uplands respectively, although the extent of increase (55%) of woody cover of all three categories was similar. The probability of change of sites from one category of woody cover to another indicate the system is tending toward a severely encroached state. The levels of encroachment recorded in this study are expected to impact livestock production.

Keywords: Aerial photographs; woody invasion

African Journal of Ranfe and Forage Science 16(1): 26–31