Climate warming-induced drought constrains vegetation productivity by weakening the temporal stability of the plant community in an arid grassland ecosystem

Abstract

An investigation of the influences of climatic warming on ecosystem function and stability is crucial to project the impact of global climate change on terrestrial ecosystems. However, few studies have applied multiple warming treatments in arid ecosystems, which play a critical role in the global carbon cycle and are among the ecosystems most sensitive to future climatic change. To explore the effects of climatic warming on plant community function and stability, moderate warming and acute warming treatments were conducted in desert grassland, Inner Mongolia, China, using free-air temperature increase facilities. Aboveground net primary production (ANPP) of plant community significantly decreased with climatic warming, particularly in warmer years with drier conditions. The decrease in ANPP was mainly caused by decreased soil moisture induced by climatic warming. Climatic warming reduced the temporal stability of the plant community by weakening plant species asynchrony and shifting key functional groups, such as perennial vs annual grass and C3 vs C4 species. Our findings indicate that climatic warming could hamper plant community productivity via decreased soil moisture and constrain plant community functioning by weakening community stability. This result highlights that shifts in plant community composition and consequent functional changes can play a key role in predicting the responses of arid ecosystems to climatic change.