Increased snowfall weakens complementarity of summer water use by different plant functional groups

Area of Science:

• Ecology
• Hydrology
• Stable Isotope Geochemistry

Background:

• Semiarid regions rely on winter snowfall as a crucial summer water source for plants.
• Understanding plant water uptake dynamics is vital for predicting ecosystem responses to changing precipitation patterns.

Purpose of the Study:

• To investigate the contribution of winter snowfall to plant water uptake throughout the growing season in a temperate steppe.
• To analyze the effects of increased snowfall on plant water use partitioning and species interactions.

Main Methods:

• Stable isotope analyses of hydrogen (δD) and oxygen (δ18O) in snow, rain, soil water, and plant water.
• Field sampling under control and increased snowfall conditions in Inner Mongolia, China.
• Assessment of water use partitioning based on plant rooting depths.

Main Results:

• Snowfall contributed to plant water uptake throughout the growing season, detectable even in late stages.
• Hydrogen isotope analysis indicated snowfall and rainfall as 30% and 70% water sources, respectively.
• Oxygen isotope analysis showed snowfall and rainfall as 12% and 88% water sources, respectively.
• Plant water use partitioning varied with species' rooting depths.
• Increased snowfall reduced complementarity in plant water use during summer.

Conclusions:

• Winter snowfall is a significant and persistent water source for plants in semiarid temperate steppes.
• Altered snowfall regimes can modify plant water use strategies and interspecific interactions.
• Findings offer insights into precipitation-ecosystem dynamics in water-limited environments.