ECOLOGICAL ASPECTS OF SOIL SEED-BANKS IN RELATION TO BAUXITE MINING .1. UNMINED JARRAH FOREST

Germinable seed stores were measured in jarrah forest soils at six sit es during one year. The overall mean seed content to a depth of 5 cm w as 292 seeds m(-2). There was a significant seasonal difference, with a maximum of 435 seeds m(-2) in summer, after the majority of species in this Mediterranean ecosystem had flowered and set seed, and a minim um of 207 seeds m(-2) in winter. There were also large site difference s in both the densities of seed present and the species represented in the soil seed store. More than 85 species were represented in the ger minable seed store from a total sampling area of 17.28 m(2). The germi nation of Acacia drummondii, Acacia pulchella, Bossiaea aquifolium, Ke nnedia coccinea, Lasiopetalum floribundum and Trymalium ledifolium wer e significantly increased by heating the soil. Smoke produced a signif icant positive germination response in one species (Trymalium ledifoli um). To maximize the contribution of the soil seed store to mine rehab ilitation, the ideal revegetation sequence is to collect the topsoil i mmediately after clearing the vegetation in summer, immediately return the soil to an area to be revegetated, and carry out all earthmoving, landscaping and seedbed preparations prior to the onset of the autumn rains.