3.3 Pathways through which warming and N addition influenced
species dominance
Structural equation modeling allowed us to disentangle the contributions
of the direct and indirect effects of warming and N addition on plant
phenology and dominance. The analyses suggested that soil temperature
and moisture at different soil depths played key roles in determining
the flowering phenology of all the studied species (Figure 3). For
C3 plants, S. breviflora, A. tenuissimum andC. ammannii , the duration of flowering decreased with increasing
soil temperature, causing declines in plant dominance. For
C4 plants, C. songorica and K. prostrata ,
flowering phenology was largely determined by soil moisture. Nitrogen
addition prolonged the duration of flowering via increasing soil
moisture, consequently leading to an increase in the dominance of
C4 plants (Figure 3).