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

Abstract

An analysis of the plant communities of the Sileza Nature Reserve and surrounding areas (± 4 124 ha) is presented. The study area falls within the Maputaland Centre o f Endemism, which is part ot the Maputaland-Pondoland Region, a centre of plant diversity rich in endemic plants and animals. A TWINSPAN classification, refined by Braun-Blanquet procedures, revealed 12 distinct, mainly grassland plant communities. A hierarchical classification, description and ecological interpretation ot these communities are presented. The level o f the water table, either directly, or indirectly through its role in soil formation, is the deciding factor in defining plant communities on the geologically young sandy substrate. Fire is an essential factor, particularly in maintaining the woody grasslands, a rare vegetation type rich in geoxylic suffrutices. and unique to the Maputaland Centre. A comparison 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 grow th form and vegetation type partitioning between the two centres. This can probably be ascribed to the relative youth (Quaternary) of the Maputaland coastal plain and its associated plant communities. Notable for their richness in Maputaland Centre endemic/near-endemic taxa. the conservation of sand forest and woody grasslands should receive high priority. Afforestation with alien trees is the most serious threat to the biodiversity of the Maputaland coastal grasslands, not only because of habitat destruction, but also through its expected negative effect on the hydrology of the region

Keywords

• Braun-Blanquet classification
• endemism
• grassland. Maputaland. phytosociology
• sand forest
• sufïrutex
• synecology
• vegetation
• water table