A comparative study of habitats of the Golden Sun Moth Synemon plana Walker (Lepidoptera : Castniidae): implications for restoration

The Golden Sun Moth (Synemon plana) is currently known from about 10-12 sit es in the Australian Capital Territory, 5-6 sites in Victoria and 1 site in New South Wales. It is listed as endangered and is protected in these stat es. Soils and vegetation of sites inhabited by S. plana and of two historic al locations were compared. The habitat of S. plana is native grassland dom inated by Austrodanthonia spp., in particular A. carphoides, A. auriculata, A. setacea, and A. eriantha. The percentage cover of Austrodanthonia spp. at currently inhabited sites was greater than 40%. Soils were variable, ran ging from sands and clays to loams. The pH of the soils was slightly acidic to basic but concentration of available P at inhabited sites was always le ss than 14 mu g g(-1). At the historical sites concentrations of available P were greater than 14 mu g g(-1) and were associated with weeds that have a competitive advantage over Austrodanthonia spp. and hence reduced the hab itat occupied by S. plana. Lolium perenne (perennial ryegrass), an exotic s pecies introduced for agriculture is common in many areas occupied by A. er iantha. A pot experiment was established to determine the effects of added phosphorus on competition between A. eriantha and L. perenne. The applicati on of phosphate did not affect growth of A. eriantha but increased the grow th of L. perenne. The growth of A. eriantha decreased when grown with L. pe renne and it is hypothesised that allelochemicals exuded by the roots of L. perenne decreased the rate of uptake of P and N by the roots of A. erianth a. (C) 1999 Elsevier Science Ltd. All rights reserved.