Vegetation of inselbergs in Zimbabwe

Abstract

Inselbergs are rounded rock outcrops, usually of Precambrian age, with sparse vegetation cover. The vegetation of inselbergs in Zimbabwe is described for the first time, based upon data sampled from 53 localities. Inselbergs support a range of habitats whose vegetation is described. Data on species richness and floristic composition of the inselberg flora (549 vascular plant, 25 bryophyte and 136 lichen species) are presented. Phytogeography and diversity of inselberg vegetation are discussed. First records for Zimbabwe are reported in lichens and vascular plants.

Factors Controlling Species Richness of Inselbergs

“…As is shown in more detail below, the mat communities on inselbergs in the Brazilian Atlantic rainforest are by far more species-rich due to a large regional species pool. In contrast, Brazilian ephemeral flush com- Porembski et al ( , 1996Porembski et al ( , 1998, Dorrstock (1994), Seine (1996), Ohlemiiller (1997) Analyzing the mechanisms that regulate the composition of plant communities is one of the major tasks of plant ecology. A vast array of empirical and conceptual studies (for surveys see Crawley 1986;Tilman 1988) exist which indicate that communities are either in equilibrium (i. e., regulated by biotic interactions) or in non equilibrium (i.e., regulated by chance and abiotic disturbances).…”

Phytogeography

“…While it is higher than the regional average on inselbergs in Zimbabwe (Seine et al, 1998), the Georgia Piedmont (Wyatt and Allison this volume), and the Seychelles (Fleischmann et al 1996) the figures are below average in Venezuelan Guayana (Groger 1995), the Guianas (Raghoenandan, Chap. 10.7,this Vol.…”

Human Dimensions and Conservation

“…Reitsma et al (1992) reports that inselbergs in Gabon are believed to be the abode of ghosts. The Zimbabwean Mambo use caves for the rainmaker's ceremony (Seine 1996). In Australia, inselbergs have an important position in indigenous mythology (Bindon 1997).…”