STIMULATIVE EFFECTS OF ARTHROPODS ON ENDOMYCORRHIZAS OF SUGAR MAPLE IN THE PRESENCE OF DECAYING LITTER

1. We examined how Acer saccharum Marsh seedlings respond in terms of biomass and mycorrhizal colonization levels to the addition of (1) soi l microarthropods and (2) decaying Litter, under microcosm conditions. 2. The addition of fauna was associated with decreased arbuscular (-3 8%) and hyphal (-30%) colonization, and increased vesicular colonizati on (+112%), with no effect on plant biomass. 3. The addition of decayi ng litter was associated with decreased arbuscular colonization (-51%) , increased hyphal (+24%) and vesicular (+117%) colonization, and extr a-radical hyphal length (+38%), and decreased shoot (-43%) and root (- 23%) biomass. 4. However, there was a strong synergistic interaction b etween decaying litter and soil fauna and the addition of both was ass ociated with enhanced arbuscular colonization (+59%), vesicular coloni zation (+85%) and increased shoot biomass (+32%), and shoot/root bioma ss ratio (+25%). 5. Understanding the dynamics involved in such intera ctions between soil organisms can have profound implications for soil management practices in agriculture, forestry and areas requiring reve getation.