Vegetation of the Sileza Nature Reserve and neighbouring areas, South Africa, and its importance in conserving the woody grasslands of the MaputalandCentre of Endemism

An analysis of the plant communities of the Sileza Nature Reserve and surro unding areas (+/- 4 124 ha) is presented. The study area falls within the M aputaland Centre of Endemism, which is part of the Maputaland-Pondoland Reg ion, a centre of plant diversity rich in endemic plants and animals. A TWIN SPAN classification, refined by Braun-Blanquet procedures, revealed 12 dist inct, mainly grassland plant communities. A hierarchical classification, de scription and ecological interpretation of these communities are presented. The level of the water table, either directly, or indirectly through its r ole in soil formation, is the deciding factor in defining plant communities on the geologically young sandy substrate. Fire is an essential tial facto r, particularly in maintaining the woody grasslands. a rare vegetation type rich in geoxylic suffrutices, and unique to the Maputaland Centre. A compa rison between the endemic complement in the subtropical coastal grasslands of Maputaland and the high-altitude Afromontane grasslands of the Wolkberg Centre of Endemism shows marked differences in growth form and vegetation t ype partitioning between the two centres. This can probably be ascribed to the relative youth (Quaternary) of the Maputaland coastal plain and its ass ociated plant communities. Notable for their richness in Maputaland Centre endemic/near-endemic taxa, the conservation of sand forest and woody grassl ands should receive high priority. Afforestation with alien trees is the mo st serious threat to the biodiversity of the Maputaland coastal grasslands, not only because of habitat destruction, but also through its expected neg ative effect on the hydrology of the region.