EMERGENCE OF EUCALYPTUS-MARGINATA (JARRAH) FROM SEED IN MEDITERRANEAN-CLIMATE FOREST IN RESPONSE TO OVERSTORY, SITE, SEEDBED AND SEED HARVESTING

The effects of overstorey, type of site, seedbed, seeding date and see d harvesting by vertebrates and invertebrates on the emergence of Euca lyptus marginata (jarrah) seedlings were studied experimentally in the northern jarrah forest of Western Australia. Seed harvesting by small vertebrates substantially reduced emergence, whereas invertebrates on ly slightly reduced emergence. Ninety per cent of seed was removed wit hin 1 day when it was on the soil surface and in the open, whereas see d removal was insignificant when the seed was covered by soil. Vertebr ates harvested seed more effectively when the understorey and litter w ere removed and the seed was more visible on the soil surface. Seed ha rvesting by small vertebrates had less impact on a site where there ha d been bauxite mining, possibly because the surrounding area was being revegetated with large numbers of seed and the area afforded poor cov er for vertebrates. Emergence was less where the overstorey was remove d compared to where it was retained, and on the rehabilitated bauxite mined site compared to the forest sites. There was no difference in em ergence between the low and high quality forest sites and so the emerg ence phase could not fully explain the variation in abundance of E. ma rginata seedlings on different quality sites. Post emergence events ar e likely to be important in explaining this difference between low and high quality sites.