Hypothesis Mechanism Effect on decomposition via Effect on decomposition via Effect on decomposition via Respective effect of PI replaceable by:
T1 T2 T3
Aboveground effects of PI Aboveground effects of PI
Less phytophagy, hence less defense production against herbivores Less phytophagy, hence less defense production against herbivores
PIA1 Litter less toxic for soil invertebrates + + Lower phenolics
PIA2 Litter with more degradable C compounds + Lower C:N ratio
Less phytophagy, hence less damage on leaf litter Less phytophagy, hence less damage on leaf litter
PIA3 Litter with less access for soil biota - - Lower leaf damage
PIA4 Slower moistening/desiccation - Lower leaf damage
More stressful conditions, hence more defense production More stressful conditions, hence more defense production
PIA5 Litter more toxic for soil invertebrates - - Higher phenolics
PIA6 Litter with less degradable C compounds - Higher C:N ratio
Belowground effects of PI Belowground effects of PI
Ambient litter different from focal oak litter Ambient litter different from focal oak litter
PIB1 Ambient decomposers naïve to focal oak litter - -
PIB2 Transfer of nutrients for decomposers + +
PIB3 Transfer of toxins for decomposers - -
PIB4 Ambient litter more acid - Lower soil pH
PIB5 Ambient litter with less water holding capacity - Lower soil moisture
PIB6 Ambient litter more aerated + Lower soil moisture
Altered vegetation period of the focal oak tree Altered vegetation period of the focal oak tree
PIB7 Delayed budburst - More days until budburst
PIB8 Shorter vegetation period + Shorter leaf duration