To date, no basin-wide vegetation mapping activity has been completed for the Limpopo River basin. Therefore, for the purposes of the RAK, Biomes and Landcover information will be used to provide indications of the distribution of vegetation and plant communities.
Biomes of Southern Africa
Biomes are defined "the world's major communities, classified according to the predominant vegetation and characterised by adaptations of organisms to that particular environment" (Campbell 1996). The word Biome is a hybrid word for Bioclimatic Zones (WWF 2010) and as this name indicates, it encapsulates the communities of plants that thrive in certain biophysical and climatic conditions and landscapes. Globally, there are six major types of terrestrial biome:
Desert
Forest
Freshwater
Grassland
Marine
Tundra
A map of the terrestrial biomes for the Limpopo River basin is shown below.
TERRESTRIAL BIOMES OF THE LIMPOPO RIVER BASIN. SOURCE: WWF 2010
As can be seen from this map the Limpopo River basin is dominated by the Savannah Grassland Biome, which is known in the region as Bushveld. Other classes include Montane Grasslands, coinciding with the higher elevation regions and mountain ranges in the central and southwestern basin. Flooded Grasslands and Savannas follow the floodplain of the southern portion of the Changane River in Mozambique, which meets Tropical and Subtropical Moist Broadleaf Forests at the river mouth at Xai Xai.
One of the greatest impacts on vegetation cover in the base is the transformation of the landscape for agriculture. This change in land cover and the associated water processes impact vegetation communities and the hydrology of the region. One perspective of this land change is reflected in the Last of the Wild analysis, presented in Biodiversity in the Basin.
Basin Vegetation Communities
As each of the countries of the Limpopo River basin uses different vegetation classification systems and methdologies, no single vegetation map exists for the entire basin. However, a crude estimate can be used to indicate the presence, absence and vigour of vegetation in the basin. A Normalised Difference Vegetation Index (NDVI) can be calculated using the red and near-infrared bands of multispectral satellite imagery. NDVI does not have a set scale, as the values are relative (one spectral band compared with another); however, it can provide a rough assessment of vegetation health at a point in time. NDVI is most commonly used for assessing broadscale vegetation health for food security monitoring. An example of such an application can be found at the Famine Early Warning System Network (FEWS-NET).
For further information on the biodiversity of the Limpopo River basin, please refer to the Ecology and Biodiversity chapter of the River Basin theme.
