Ecology and population biology of Euphorbia perangusta (Euphorbiaceae) in the Transvaal, South Africa

Abstract

The conservation status of Euphorbia perangusta R. A. Dyer, an endangered plant restricted to the Marico District of the Transvaal, South Africa, and adjoining parts of Bophuthatswana was determined. The distribution, habitat and population dynamics of E. perangusta are discussed.

The monitoring of the largest known population has revealed that this population has declined rapidly since the onset of a drought in 1983. The major cause of this decline appears to be the destruction of the plants by porcupines which feed on E. perangusta during droughts.

It appears that, during droughts,  E. perangusta is restricted to rocky ridges because there is an increase in porcupine damage on more accessible populations. The species is also subjected to other factors which reduce flower formation in a large proportion of plants. If these factors continue to operate, the species could become extinct in the near future. Conservation recommendations are discussed.