Abstract: Communities with more species could have a greater variety of species?characteristics, leading to more effective use of limiting resources through niche partitioning (complementarity) and therefore greater production. The effect of phenological complementarity (PC) on ecosystem production has not been fully investigated. The seasonal responses of all vascular plant species were tracked to test the effect of phenological complementarity on ecosystem production within a natural stable steppe community. Although a significant phenological pattern was observed, PC had no significant correlation with community production. The value of PC varied with years, but was observed only in a relatively narrow range during the experimental period. Species diversity (richness and evenness) had no correlation with the ecosystem production. The results suggest that the effect of PC may be saturated and has no contribution to the improvement of ecosystem production in a stable natural grassland community with abundant species.

Key words: ecosystem function, phenological complementarity, steppe community, temporal variation, total annual net primary productivity.