Researchers at the Institute of Applied Ecology (IAE) of the Chinese Academy of Sciences have shed light on how the timing of snowmelt affects the plant communities in grasslands, which are vital ecosystems around the world.  

In arid and semi-arid regions, winter snowfall serves as a crucial water source during the vegetation greening period, and snowmelt drives the start of the growing season. However, with global temperature and precipitation changes, winter snowfall amounts, snow depth, and snowmelt time are shifting, potentially altering early spring soil temperatures and moisture conditions. Surprisingly, snow changes have received less attention compared to other global change factors like nitrogen deposition, rainfall fluctuations, and warming.

 Led by Dr. WANG Zhengwen, the Ecological Stoichiometry team of IAE set up an experiment to mimic the effects of changing snow patterns at Erguna Forest-Steppe Ecotone Research Station. Over four years, the researchers simulated increased snow depth, delayed snowmelt, and combined these treatments to assess their impact on aboveground net primary productivity (ANPP) and plant species composition. 

 Interestingly, simply adding more snow didn't affect the plant communities. However, delaying the melt led to some surprising results. The plants started growing later (delayed phenology), but overall growth (measured by aboveground net primary productivity or ANPP) increased. This upside came with a downside: the diversity of plant species decreased, and the overall plant community composition shifted. The researchers attributed the changes in plant communities largely to the greater sensitivity of graminoids (grasses) to snowmelt delay compared to forbs (broad-leaved flowering plants that are not grass-like). 

The study also revealed an interesting interaction: under snowmelt delay treatments, further adding snow excessively prolonged snow persistence, counteracting the effects of snowmelt delay on plant communities. 

This study, published in the journal Science of the Total Environment, underscores the importance of the date of snowmelt for grassland ecosystem structure and function.

 

YUE Qian

Institute of Applied Ecology, Chinese Academy of Sciences

Tel: 86-24-83970317

E-mail: yueqian@iae.ac.cn

Web: http://english.iae.cas.cn