Abstract
Diversity-stability relationships in grasslands depend on the
environment. Climate change and soil degradation potentially alter soil
pH and community stability within grassland environments, although it
remains unclear how soil acidity and alkalinity affect
diversity-stability relationships. We conducted a three-year experiment
of acidification and alkalization treatments in an arid grassland in
northern China, and found that increasing and decreasing soil pH reduced
community species richness, community diversity, community and dominant
species asynchrony, and biomass stability. Soil acidification reduced
community stability by reducing dominant species stability. Soil
alkalization reduced community stability by reducing species asynchrony
and dominant species stability. Acidification significantly enhanced the
availabilities of soil NO3—N, P, and K, but did not affect the
concentrations of soil total C, N, and P. By contrast, alkalization
significantly reduced soil total C and N, but did not affect the
availabilities of soil N, P, and K. Structural equation model analysis
revealed that altered soil pH affected soil nutrients associated with
species asynchrony and community stability, which indicated the
importance of soil nutrients in driving community stability. Our results
suggest that soil pH–mediated community stability is mainly driven by
dominant species stability rather than diversity. This study provides
novel insights indicating that arid grassland stability would be
weakened under changing soil pH, subsequently leading to land
degradation and reducing long‐term productivity and sustainability.