Changes in the distribution of emergent aquatic plants in a brackish South African estuarine-lake system

Abstract

Vegetation mapping in the Wilderness Lakes indicated that, between 1975 and 1997, prominent increases occurred in the distribution of the mapping units Phragmites australis (53.9ha; +53%), grass or fields (23.1ha; +35%) and scrub or trees (12.2ha; +45%). Over the same period the area of human habitation more than doubled (10.8ha to 23.3ha). Substantial declines occurred in the distribution of Juncus kraussii (76.2ha; –243%), Schoenoplectus scirpoideus (10.1ha; –38%) and low scrub or fynbos (7.8ha; –66%). Six new plant species were recorded in stands large enough for identification from aerial photographs. The most prominent changes occurred at Langvlei and the Serpentine Channel.