Hartbeespoort Dam in South Africa has a new invasive aquatic weed to battle, Salvinia minima. The proliferation of common salvinia, just as water hyacinth came under biological control through the combined efforts is no coincidence.
In areas that experience high levels of nutrient inflow (pollution), the control of one aquatic weed opens resources to other potentially invasive plant species creating a ‘secondary invasion event’. In the case of common salvinia, the ‘secondary invasion event’ is taking place just as resources such as light availability, space and nutrients, otherwise used by water hyacinth, have become available.
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