Extreme precipitation increases the productivity of a desert ephemeral plant community in Central Asia, but there is no slope position effect

摘要

Abstract Questions Anthropogenic climate change has become a critical environmental problem and is profoundly affecting various ecosystems, especially desert ecosystems. However, very few studies have explored the effects of extreme precipitation on the community structure and ecosystem functions in drylands. Moreover, whether local microtopography will interact with extreme precipitation on plant growth by changing water retention and other processes is still unclear. Location The Gurbantunggut Desert in Central Asia. Methods We conducted a two‐year field experiment to assess the effect of extreme precipitation (+65% of ambient growing‐season precipitation amounts) on the composition and productivity of a desert ephemeral plant community growing in sand dunes of the Gurbantunggut Desert in Central Asia. We further determined how much slope position modulates this response. Results We found that the cover, density, height, species richness, and biomass of ephemeral plants increased with an increase in precipitation, and the strongest direct effect of biomass was a positive effect on density of ephemeral plants. Additionally, no significant differences in the sensitivity of biomass to the increased precipitation were found between slope positions. Conclusions The results indicate that extreme precipitation primarily increased the above‐ground net primary production by increasing the density, rather than the height and species richness, of the ephemeral community; no interactive effects were observed between sand dune slope positions and the sensitivity of biomass to the extreme precipitation treatment.