Tree canopies facilitate invasion of communal savanna rangelands by Lantana camara

Abstract

This study investigated pattern in the distribution of the alien invasive shrub, Lantana camara L., in communal versus conservation land-use in a lowveld savanna. Pattern was investigated relative to land-use type, and sub- or inter-canopy micro-sites. Lantana was significantly more prevalent on communal lands than in the conservation area, and in sub-canopy micro-sites than inter-canopy micro-sites. The communal lands had significantly lower herbaceous biomass than the conservation area, and Lantana prevalence was inversely related to herbaceous biomass. Higher prevalence of Lantana in communal areas was probably due to more intense disturbance of the herbaceous layer in this land-use type, although this was not conclusively demonstrated. The difference in the prevalence of Lantana between sub-canopy and inter-canopy micro-sites is most likely explained by either seed dispersal patterns imposed by avian dispersal agents and/or micro-site variation. An assessment of population size class structure of Lantana in the communal lands suggested that the population is stable and rapidly recruiting.