The Dynamics of the Indigenous Forest-Fynbos Ecotone in the Southern Cape

Abstract

SYNOPSIS A hypothesis that the indigenous forest colonises fynbos and disturbed sites in the Southern Cape has been tested by surveying the forest-fynbos ecotone and the adjoining fynbos and analysing the data by means of reciprocal averaging and factor analysis. On all the study sites except one the ordination of the environmental factors with factor analysis showed no co-incidence with the present forest-fynbos ecotone and it was concluded that the forest ecotone had been articifially induced on these sites. No forest species were regenerating in the adjoining fynbos. Possible reasons for this are closed nutrient cycles of the shallow-rooted trees, the inability of the trees to withstand regular burning and an unfavourable macroclimate and microclimate. Soil moisture is important, especially in the marginal areas. Except in the case of soils derived from Enon conglomerates or granites, soil type is not a limiting factor for forest development. Fynbos is not seral to forest, but a different vegetation type replacing forest where possible. Key words: forest ecotoneindigenous forestfynbosSouthern Cape