Status of biodiversity

Biodiversity refers to the degree of variety among living organisms that occur at a place – the more diversity the healthier the ecosystems. Three common ways to measure diversity are: alpha diversity, which measures the number of different kinds of creatures in an area (species richness); beta diversity, which measures species diversity between ecosystems (habitat patchiness); and gamma diversity, which measures how many creatures in an area also occur elsewhere (affinity).

South Africa’s grasslands have a high alpha diversity, moderate gamma diversity and high rates of beta diversity where topographical and environmental gradients are steep.

• Of the 72 vegetation types in the biome, 2 are listed as critically endangered, 18 are endangered and 27 are classed as vulnerable.
• 83% of river ecosystems are ranked as threatened, with 48% critically endangered.
• The biome contains South Africa’s national bird, the blue crane, the critically endangered wattled crane and Rudd’s lark.
• Of the 195 reptile species endemic to South Africa, 22% are found in the biome.
• A third of the 107 threatened South African butterfly species occur in the grasslands.

Priority Areas

An assessment of conservation priorities in the grasslands identified broad biodiversity priority areas (36,7% of the biome) that are located across this large biome. These show what needs to be conserved to ensure sufficient representation of biodiversity patterns and processes.

Because the biodiversity of greatest importance is largely found on private commercial, communal lands and in pockets within urban centres, it is not feasible to create large protected areas and other strategies are needed. An alternative approach is to work with landowners and producers to enable them to become stewards of their rich biodiversity.