The occurrence of C and C grasses in fynbos and allied shrublands in the South Eastern Cape, South Africa.

There are roughly equal numbers of C and C grass species in fynbos and allied shrublands of the warm temperate coastal regions of the south eastern Cape. Subtropical-tropical C species have the highest relative cover in all shrubland types, particularly in renosterveld communities on moderately fertile soils. Physiological characteristics of C and C grasses predict that C species will be most abundant in cool, shaded sites. This prediction, and the hypothesis that relative C grass cover would be highest on infertile soils, were tested by correlation and regression analyses. Results show that C grass cover is significantly correlated with increased post-disturbance vegetation age, low intensity grazing, high litter cover and cool, steep, poleward slopes. All these factors contribute to lower growing season temperatures, favouring the competitive growth of C species. Amongst the soil variables, high sand content and low levels of total nitrogen emerged as predictors of high relative C grass cover.