Response of plant species richness and ecosystem functioning to
aridity and land-use
Plant species richness, aboveground biomass, and SOC decreased with
increasing aridity (Table 1, Figs. 1, 2). Grazing reduced plant species
richness, aboveground biomass, and SOC (Fig. 2), and the negative
effects on species richness and SOC were greater at dry sites (aridity ×
grazing interaction effect in Table 1). Haying increased species
richness and reduced aboveground biomass, but did not affect SOC (Fig.
2). Haying had a greater negative effect on aboveground biomass at dry
sites (aridity × haying interaction effect in Table 1).
Plant species richness was positively associated with aboveground
biomass and SOC, and this relationship became stronger with increasing
aridity (Fig. 3 and the aridity × species richness interaction effect on
aboveground biomass in Table 1). The slopes of the relationships between
plant species richness and aboveground biomass as well as SOC along the
aridity gradients showed that species richness had a greater effect on
SOC than on aboveground biomass, and both effects increased with
increasing aridity.