Effect of simulated warming on Leymus chinensis grasslands of northeast China

Mean global temperatures have risen by almost 1°C since 1850 and are predicted to continue to rise through to the end of the century. Understanding how grasses are affected by a long-term increase in temperature is crucial to predicting the future impacts of climate change. Grasslands occupy over 3.5 billion hectares of land and store 20 % of the world’s soil carbon. Yet few experimental studies have comprehensively investigated how warming affects the dynamics of grassland ecosystems.

In a recent study published in AoBP, Guo et al. investigated the effects of simulated elevated temperatures on Leymus chinensis grassland in Northeast China. Measurements of soil properties, ecosystem gas exchange and plant physiological properties were made under elevated temperatures. Warming was found to increase soil organic carbon content, soil total nitrogen, shoot biomass, ecosystem respiration rates and ecosystem water use efficiency compared to ambient controls. However, reduced net ecosystem CO₂ exchange and evapotranspiration were also observed. These results suggest that warming could significantly alter ecosystem level carbon and water fluxes. At the plant scale, leaf concentrations of glucose and fructose were seen to increase under warming whilst sucrose synthesis was significantly inhibited. To adapt to elevated temperature, L. chinensis also accumulated K⁺ and reduced Na⁺ to maintain intracellular ion balance and sustain a number of enzymatic processes. The authors state that their study explains the primary metabolic responses of L. chinensis to warming and that linking these responses to ecosystem level processes allows us to better understand and predict future responses to climate change.