CONCLUSIONS
The stimulating effects of plant diversity on plant biomass (Loreau &
Hector 2001; Hooper et al., 2005; Cardinale et al., 2013; Liang et al.,
2016), root productivity (Ma & Chen 2016; Ravenek et al., 2014; Oram et
al., 2017), and soil fauna activity (Birkhofer et al., 2011; Spehn et
al., 2000) have been shown before. However, our high temporal resolution
data show that plant diversity effects on plant and soil processes
change throughout the year. Root production is initiated during winter,
right after the end of the aboveground growing season. With this, the
positive plant diversity effects on aboveground processes may result
from earlier plant diversity effects on the root system operating over
winter. Unraveling the patterns of aboveground-belowground phenological
synchrony offers a significant promise to advance underexplored areas of
plant and soil ecology by adding an essential layer to understanding
aboveground-belowground interactions (Ochoa-Hueso et al. 2021). In the
context of biodiversity and ecosystem functioning,
aboveground-belowground phenology may broadly advance the interpretation
of species coexistence. It can help propose new mechanisms on whether
and how biodiversity enhances ecosystem functioning. Overall, this work
shows fundamental differences in the phenological patterns of leaf and
root production and the activity of soil organisms, stressing the role
of plant diversity in modulating the phenology of plant processes and
soil fauna activity.