5 CONCLUSIONS
Our study focuses on the phytolith and PhytOC contents of different
plant communities and their constituent species on a climate gradient in
the semi-arid steppe region of the Mongolian Plateau. Our results show
that the phytolith and PhytOC contents differ among plant species, and
that climatic factors affect phytolith and PhytOC production rates of
steppe communities mainly through affecting plant production, whereas
their effects on the phytolith and PhytOC contents in plants are
relatively small. Our results also demonstrate that plant aboveground
biomass (AGB) and PhytOC content are strongly associated with the
current-year climate and bioavailable Si content in the soil, while the
variation in plant belowground biomass (BGB) and PhytOC content across
sites was more correlated with the long-term mean values of climatic and
soil factors across the sites, reflecting the perenniality of the
belowground part of steppe plants. More studies are warranted to
quantify annual PhytOC production from plant belowground part with the
effects of plant perenniality
incorporated.