A research team led by Prof. LIU Lingli from the Institute of Botany of the Chinese Academy of Sciences (CAS) uncovered how changes in winter snowfall influence plant water-use strategies, ultimately stabilizing productivity in semi-arid grasslands.

The findings, published in Ecology, provides compelling evidence that plant communities can optimize water acquisition and utilization, thereby enhancing the stability of biomass production through coordinated changes in plant physiology, species reordering, and root distribution under altered snow regimes.

Through a five-year snow manipulation experiment in Inner Mongolia, the researchers demonstrated that increased snow cover enhances ecosystem water use efficiency (WUE), boosting both productivity and its temporal stability. They integrated paired stable isotope measurements of δ¹⁸O and δ¹³C from 32 temperate grassland species to reveal how plant communities optimize water acquisition and utilization under altered snow regimes.

The study showed that deepened snow cover enhanced the ecosystem WUE, thereby promoting grassland productivity and its stability. Notably, this effect of deepened snow could persist until the peak and later growing season.

The improvement in productivity stability was closely linked to diverse behaviors of plant stomata. Additionally, communities with more grasses tend to exhibit higher stability, because grasses can respond rapidly to environmental changes. Deepened snow intensified water loss from transpiration via higher stomatal conductance, whereas grasses were still able to maintain a high WUE to stabilize the productivity through enhanced photosynthetic capacity. Deepened snow also increased the root biomass, improving plants' ability to obtain more water and further promoting the productivity stability.

This study provides valuable insights into how grassland productivity adapts to climate change through shifts in water-use strategies. These findings also emphasize the potential diverse ecological impacts resulting from shifts in snow regimes, especially in water-limited ecosystems.

Plants' water use strategies in how winter snowfall stabilizes productivity in semi-arid grasslands (Image by LI Ping and Jalaid Nairsag)