The Association and Interaction of <em>Acacia decurrens Willd</em>. with Its Indigenous Species at the Waterberg Area, Limpopo Province, South Africa

Invasive species have been identified as the second main cause of biodiversity loss after habitat destruction and the main cause of species extinctions in Island ecosystems. The study was carried out in the farms found in the north west and south west of Mookgophong in Limpopo Province, South Africa. The number of invasive alien species and indigenous species were counted in each quadrat. The heights and canopy covers of both indigenous and invasive alien species were measured and compared. The invasive alien plant species were found dominating throughout the study area. The indigenous species were found to be very low even in areas where they occur alone. There are in a number of cases inverse relationships between the indigenous and the invasive alien plant species, where the pattern of distribution was that where invasive alien plant species dominated indigenous ones would be insignificant. Special attention therefore needs to be given to invasive alien plant species before they lead to local and / global extinction of the majority of our indigenous species.