Management implications of recent research into the effect of bitou bush invasion

We review recent research into the impact of bitou bush (Chrysanthemoides monilifera subsp. rotundata (DC.) Norl.) on coastal ecosystems which suggest this weed is having widespread impacts on ecosystem services, flora and fauna. Increased decomposition rates and altered nutrient cycling accompany changes in plant community structure and composition. Changes in invaded habitats influence invertebrate and bird assemblages. We summarize research that shows that the establishment phase of seedlings is the key phase where bitou bush out competes native species through both resource and interference competition mechanisms. Control of bitou bush at sites by hand spraying and/or hand pulling, and aerial spraying alone do not restore all species that were in uninvaded coastal communities, although these management techniques can reduce seed availability of bitou bush. We suggest that destruction of bitou bush seedlings should be specifically targeted in weed management strategies and that long term management plans are developed to ensure control of secondary weeds that are at risk of invading after bitou bush control. These activities should include using fire to encourage native seed germination and to potentially remove volatile allelopathic chemicals in the soil. Management strategies should also include replanting schemes to increase species richness of all plant structural groups to build ecosystem resilience.