Soil water availability in desert ecosystems is often highly variable in space and time due to the scarcity and variability of precipitation. The spatial and temporal variations of soil water are key determining factors for plant distribution and community structure in desert ecosystem.

How do desert plants adapt to seasonal variations in soil water and the periodic and chronic water scarcity in desert ecosystem? Especially under the future climate change scenarios with predicted increase in the frequency and intensity of drought and changes in regional precipitation patterns.

Scientists from the Xinjiang Institute of Ecology and Geography (XIEG) of the Chinese Academy of Sciences studied the water sources of six desert shrubs co-occurring in the Gurbantonggut Desert to examine contrasting water use patterns adopted by the co-existing desert shrubs.

Gurbantonggut Desert (the second largest desert in China) ecosystem is the most important desert ecosystem, and C₃ and C₄ shrubs are its dominant species. C₃ and C₄ plants adopt far distinct photosynthetic path ways due to differential leaf structure with C₄ having chlorophylls in the bundle sheath cells. Theses structural differences contribute the contrasting carbon assimilation and water use efficiencies of the two types of plants.

The results of the study showed that desert plants used different water sources in space and time, and adopted their root functioning to adjust to the temporal and spatial variations in soil water availability, which is one of the key strategies for desert shrubs to deal with periodic water scarcity.

"The differential water uptake between shrubs with distinct rooting depth is an important mechanism," said MA Jianying, leading scientist of the study from XIEG, "which enables desert shrubs to partition ecological niche and co-exist in water limited ecosystem."

In the meantime, distinct shoot eco-physiological performance occurred between shrubs with similar seasonal water uptake pattern under the same soil water condition, which might be beneficial to shrubs to lessen the competition to the limited water sources, according to MA.

The study entitled "Water use patterns of co-occurring C₃ and C₄ shrubs in the Gurbantonggut desert in northwestern China" was published in Science of the Total Environment.