The Gouritz Cluster Biosphere Reserve is globally unique as it is the only area in the world where three recognized biodiversity hotspots, the Fynbos, Succulent Karoo and Maputoland-Tongoland-Albany hotspots, converge.
The entire domain falls within the Cape Floristic Region - the smallest, but one of the richest of the six floral kingdoms of the world. The biosphere reserve is rich in endemic plant species, with at least 670 of the ca. 5 000 plant species present endemic to the biosphere. Even the arid inland portion of the biosphere reserve is rich in endemic species, with at least 400 of the 3 200 plant species restricted to the biosphere reserve.
The biosphere also plays an important function to conserve threatened larger mammals and endemic invertebrate species. Of critical importance to marine biodiversity along the local coastline is the role of estuaries to act as nurseries for marine species. Here an important function of the biosphere reserve is to maintain the flow of freshwater from the uplands into these estuaries, to retain the function of these estuaries as nurseries for important commercial marine species and marine biodiversity.