Effects of leaf litter on woody seedlings in xeric successional communities

We investigated the effect of leaf litter on the establishment of Eucalyptu s incrassata, a mallee eucalypt. It has been suggested that litter accumula tion may hinder seedling establishment, and that the removal of litter may be one of the mechanisms through which fire enhances recruitment. We conduc ted factorial experiments testing the effects of three kinds of leaf litter on E. incrassata seeds and seedlings at three contiguous sites with differ ent land use histories. One site was an uncleared E. incrassata open mallee woodland (Mallee site), one a cleared area that had been ungrazed for abou t five years (Pasture site) and the third an area of mallee rolled some 40 years ago and permitted to regenerate (Regrowth site). Litter had no effect on emergence of planted E. incrassata seeds, but emergence differed betwee n sites. Overall, the percentage of seeds that germinated and emerged was s ubstantial (mean 35.2% +/- 25.9%). Seedling shoot biomass did not differ be tween sites or litter treatments. Although seedlings grown in Pasture litte r suffered higher mortality rates, overall mortality rates were low (mean 1 3.2% +/- 15.5%), suggesting that leaf litter has little effect on recruitme nt rates during winter and spring. We conclude that leaf litter does not af fect emergence or growth in young E. incrassata seedlings during winter and spring, when most establishment occurs. Our results emphasize the difficul ty in predicting litter effects on recruitment.