The response of native ant communities to an alien invasive species (Chromolaena odorata) - the effect of temporal variation in invasion and clearing

Alien invasive species can potentially alter each and every trophic level of the ecosystem through its action of habitat change. Chromolaena odorata is an aggressive invader that has the widest distribution of all alien invasive plant species within the Hluhluwe- iMfolozi Park. It is known to invade to an impenetrable extent, shading out and competitively excluding large areas of native vegetation. Ant assemblages of intact native vegetation were compared with ant assemblages of vegetation invaded by C. odorata for different time periods and also to ant assemblages in vegetation cleared of C. odorata for different time periods. Results showed species compositional changes and ant faunal abundance declines for habitats with long invasion periods compared with recently invaded and intact habitats. Clearing of C. odorata seemed effective as no difference in ant faunal abundance was found between cleared and intact habitats. The effect and changes associated with C. odorata invasion thus seems to be reversible and native ant faunal assemblages may be restored and likely reflects similar responses of other fauna. Temporal assessment also indicated important differences in long and short term effects of invasion and clearing.