Predicting the distribution of fynbos and succulent karoo biome boundariesand plant communities using generalised linear models and geographic information systems

Vegetation survey data from Matjiesrivier Nature Reserve, in the eastern Ce derberg Mountains of the fynbos biome, were used to model the distribution of fynbos and succulent karoo biomes and plant communities. Predictions wer e based on generalised linear models (GLMs) with the presence or absence of a biome or community as the response variable. Geology, altitude, radiatio n and landtype, which were derived from remotely-sensed sources (maps, aeri al photographs and digital terrain models). were used as explanatory variab les in the GLMs. The boundary between fynbos and succulent karoo could be p redicted accurately based on geology and altitude alone. Fynbos occurred on sandstone above 800m; succulent karoo occurred On sandstone below 800m, or on shale at any altitude. Community distributions were less accurately pre dicted, but could be used to generate a geographic information system (GIS) map similar to a vegetation map derived from ground survey. These models c an be used to map vegetation over large areas in the fynbos/succulent karoo ecotone with relatively little effort or cost.