An experiment in a tropical ecosystem
Location: Ndumo Game Reserve, KwaZulu Natal, South Africa
Ecosystems in Ndumo Game Reserve have been greatly distorted by humans, adding a deeper level of interest for the scientifically curious. Indeed, Ndumo is deeply scathed by human history. Our bio-travels investigates some of this scathing.
The many-stemmed false-thorn is an unusual species in two main ways. Firstly, it differs from other false-thorns (Albizia spp.) in combining a multi-stemmed growth-form with both deciduousness and a lack of spines. Secondly, it dominates patches of low forest in Ndumo despite plenty of competition from more conventional nitrogen-fixing members of the same family (Mimosaceae), such as horned thorn (Acacia grandicornuta). Our explanation for the local success of many-stemmed false-thorn is linked to the loss of the African bush elephant. We believe that this plant was originally controlled by the elephant, to which its growth-form is specifically adapted as a defence . With this control released by the local extermination of the elephant, the many-stemmed false-thorn has increased to patchy dominance in Ndumo. Indeed, it should now replace the fever tree in the mind of the educated visitor as the symbolic plant of this location – which is ironic because Albizia is a cosmopolitan genus and the growth-form of this subspecies resembles that of mallee eucalypts in Australia, rather than the typical flat-topped trees of Africa. .