The ant (Hymenoptera: Formicidae) fauna of coastal heath in south-west Victoria: effects of dominance by Acacia sophorae and management actions to control it

Abstract

There has been increasing emphasis on the use of ant communities as indicators of recovery during and after minesite rehabilitation. This study also focuses on ants as indicators of recovery but, in this case, assesses the success of active management of coastal heath vegetation. Remnants of coastal heath near Portland in south-west Victoria are very diverse communities of considerable conservation significance. However, many remnants are suffering a serious loss of plant diversity as they become dominated by the native Coast Wattle Acacia sophorae. In an attempt to reverse these declines, heath dominated by Coast Wattle is being actively managed to encourage natural regeneration of diverse heaths. Monitoring of ant communities has documented this regeneration of the vegetation and has attempted to assess the effectiveness of two different management methods, burning and cutting. Results of pitfall trapping over two years have shown considerable difference in the ant communities of two different intact heath types (the similarity index was a low 0.34). Also clearly illustrated is the detrimental effect that dominance by Coast Wattle has on ant community diversity. The diversity index of intact heath was 0.93 compared to 0.61 and 0.50 for two sites dominated by Coast Wattle. Trapping has also shown improvement in the ant communities following burning or cutting of Coast Wattle. However, our results suggest that complete recovery will require a considerable time and that it is too early to determine the relative effectiveness of different management techniques.