Figure legend
Fig.
1. (a) Trajectories by which phylogenetic isolation (PI) of a focal
tree might affect litter decomposition and how to, tentatively, infer
them. Trajectory 1 (T1, single arrow line): effects of PI on
decomposition mediated via the abundance and diversity of
decomposers. Tentatively inferred from the abundance/diversity terms in
multiple regression analyses [abundance (or diversity) + PI +
abundance/diversity * PI -> Decomposition]. Trajectory 2
(T2, double arrow line): effects of PI on decomposition mediatedvia the efficiency of decomposers. Tentatively inferred from the
abundance/diversity * PI interaction terms in multiple regression
analyses [abundance (or diversity) + PI + abundance (or diversity) *
PI -> Decomposition]. Trajectory 3 (T3, triple arrow
line): effects of PI on decomposition mediated via the physical
conditions of decomposition. Tentatively inferred from the PI terms in
multiple regression analyses [abundance (or diversity) + PI +
abundance (or diversity) * PI -> Decomposition]. Positive
effects on decomposition that are mediated via the biotic
trajectories T1 and T2 may also increase the proportion of13C accumulated through the food chain. (b)
Phylogenetically closely (left) and distantly related (right) neighbors
may affect decomposition of litter of a focal tree via (i)
above-ground processes affecting litter quality via abiotic and
biotic mechanisms (microclimate, shared enemies, competition); and (ii)
below-ground processes affecting the decomposition of a given litter
quality via biotic and abiotic mechanisms (microclimate,
decomposer community). (c) Experimental design: Transplantation litter
between phylogenetically isolated and non-isolated trees permits to
disentangle above-ground from below-ground effects.
Fig. 2. Effects of phylogenetic isolation aboveground and
belowground (PIA and PIB) in multiple regression analysis on the mass
loss, the C loss and the N loss of the oak litter (left panel); (b) the
microbial biomass, the abundances of Acari and Collembola in the oak
litter (right panel). Empty circle and dashed line stand for the effects
of PIA, solid line and solid point stand for the effects of PIB. *
indicates partial residuals. Significant effects (P <
0.05) are shown in regression line. r2 represents the
explanatory power of each model.
Fig. 3. Effects of
phylogenetic isolation aboveground (PIA) and belowground (PIB) on carbon
isotopes (13C/12C) of oak litter
after 8 and 14 months according to multiple regression analysis. Empty
circle and dashed line stand for the effects of PIA, while solid line
and solid point stand for the effects of PIB. * indicates the partial
residuals. Significant effects (P < 0.05) was shown in
regression line. r2 represents the explanatory power
of each model.