FACTORS LIMITING THE RECRUITMENT OF EUCALYPTUS-SALMONOPHLOIA IN REMNANT WOODLANDS .2. POSTDISPERSAL SEED PREDATION AND SOIL SEED RESERVES

This study examined post-dispersal seed predation and soil seed reserves in four remnant populations of E. salmonophloia in the central wheatbelt of Western Australia to determine the effect of these factors on recruitment. Diurnal observations of post-dispersal seed predation at regular intervals of 2 months were undertaken over a 12 month period using artificial baits. Four species of ants were seen removing seeds from artificial baits regularly. Surveys of soil seed reserves revealed that E. salmonophloia does not form a soil seed bank despite a continual seed rain from canopy seed reserves. These observations suggest that ants probably destroy a large proportion of E. salmonophloia seed following dispersal. Burial of E. salmonophloia seeds in the soil in autumn, winter, spring and summer suggest that any seeds which do escape predation are unlikely to persist in the soil for much longer than 12 months and probably germinate with the onset of winter rains. Both the depredation of seeds by ants and the short term viability of seed in the soil contribute to the inability of E. salmonophloia to form a soil seed reserve.