Results
Decomposition rates and stabilization in 10
mountains
Across the 10 mountains, the decomposition rate (k ) ranged from
0.002 to 0.05 (0.02 on average), and the stabilization factor (S )
ranged from 0.006 to 0.35 (0.13 on average). JFS experienced the fastest
mass loss (k = 0.02), which was significantly higher than that in
six mountains on its east side (Fig. S2). The highest mean Soccurred in EMS and YMT (0.18), which was significantly higher thanS in GMT and the five eastern mountains (Fig. S3). There were no
significant correlations between k and S (except DBS)
(Fig. S4).
Although both significant and non-significant correlation existed, there
was a consistent pattern in each mountain that k decreased along
elevations (but see a slight hump-shape in YMT), and an opposite trend
for S (Fig. 2). For k , the significant elevational pattern
was mainly found for four western mountains (GMT, YMT, EMS, and JFS) and
the northmost mountain (DBS). For S , the statistically
significant trend occurred in three western mountains (GMT, YMT, and
JFS), and the southernmost mountain (BWL).
The importance of microclimate in
decomposition
Among 10 climatic and non-climatic variables, soil microclimate related
variables, mainly Temp, TempV, and MoisV, emerged as the most important
factors in controlling litter decomposition in the western mountains
(Figs 3-4, Table S2). Across all mountains, k was mainly impacted
by soil temperature (coef. = 0.48, P < 0.001)
and its variation (coef. = 0.36, P < 0.001),
while S was subjected to significant effects from all
microclimatic factors, with particularly strong relation with soil
temperature (coef. = -0.46, P < 0.001) and the
variation of soil moisture (coef . = -0.36, P <
0.001) (Fig. 5).
The effects of non-climatic drivers in
decomposition
Non-climatic factors, i.e., tree diversity, soil (pH and P), and
microhabitat (litter thickness, canopy cover, and slope) emerged as
important as soil microclimate in western mountains and the northmost
mountain (DBS) (Figs 3-4, Table S2). Among mountains, three
representative factors (tree diversity, soil pH, and slope) showed
substantially spatial variations in its relations with k andS (Fig. 6). Across all mountains, tree diversity ranged from 4 to
93 and increased k significantly (coef. = 0.25, P< 0.001). Soil pH (ranged from 3.06 – 7.16) and slope (0.25
– 42.5) had no significant effect in this respect. For S , we
found no significant effects of tree diversity but a significantly
negative association with soil pH (coef . = -0.17, P< 0.001) and slope (coef . = -0.14, P <
0.001).