Simulated precipitation change drives plant diversity and biomass change in the desert steppe

Background There is a large uncertainty regarding the direction and magnitude of projected changes in the pattern and quantity of precipitation in future climate change scenarios. As changes in precipitation are likely to greatly impact plant diversity and biomass in desert ecosystems, we undertook a water addition/exclusion experiment to quantify the responses of plant diversity and biomass.Aims To quantify the short-term impacts of changing the quantity of precipitation on plant species diversity and productivity in a desert steppe ecosystem.Methods A simulated precipitation manipulation (addition and exclusion) experiment was made with four treatments: precipitation decreased by 50% (P-50%), precipitation increased by 50% (P+50%), precipitation increased by 100% (P+100%) and natural precipitation (Control).Results The richness of annual and biennial species was related to treatment; above-ground biomass increased in dry years in the P+100% treatment. Water addition had no statistically significant impacts on below-ground biomass.Conclusion Increase in above-ground biomass with added precipitation in a drought year was mainly contributed by perennial grasses, suggesting that, from a management point of view, perennial grasses should be the focus of mitigation of projected future precipitation changes.