The control of alien vegetation is one of the important parts of reserve maintenance and needs a lot of attention. Invasive or alien vegetation is a big threat to the natural vegetation because it competes for the same limited resources. These species usually don’t have natural predators, so they can be more successful than indigenous species. The main invasive species we are dealing with on Olifants West Nature Reserve are sweet prickly pears (Opuntia ficus-indica), queen of the night (Cereus jamacaru) and cocklebur (Xanthium strumarium). The prickly pears and the queen of the nights occur all over the reserve, whereas the cocklebur occur only in the drainages and along the river. Another alien species that also occurs on the reserve is the climbing harrisia (Harrisia balansae) and these are also found in any type of terrain.
There are three main ways to treat alien vegetation: mechanical, biological and chemical. The two main treatment methods we use on Olifants West are chemical and biological as they are the most effective.