HABITAT SEGREGATION BY SEROTINOUS SHRUBS IN HEATHS - POSTFIRE EMERGENCE AND SEEDLING SURVIVAL

Seeds of two serotinous shrub species generally restricted to the drie r edges, and two serotinous shrub species commonly confined to the wet ter drainage channels of upland sedge-heaths were assessed for germina bility and used in manipulative field experiments. In post-fire field experiments the effects of habitat and manipulated soil moisture were examined to test if the distribution of adult plants wits influenced b y soil moisture at seed germination. The effects of habitat on seedlin g survival for 11 months were also assessed. One species from the edge zone, Banksia marginata Cav., and one from the channel zone, Hakea mi crocarpa R.Br., had germination preferences corresponding to the distr ibution of adult plants. The other edge species, Hakea dactyloides (Ga ertner) Cav., did not show a significant preference for either zone. T he second channel species, Callistemon pityoides F.Muell., did not ger minate in the field or in a laboratory germination trial. Some evidenc e for soil-stored dormancy related to temperature and or waterlogging was found in both Hakea species. Overall the results suggest that for two species habitat segregation occurs when seeds are incorporated int o the seed-bed and germination occurs. No differential survival effect s across habitats were found in the first year of growth.