Study links vegetation growth to reduction in desert creep

LANZHOU — A study by Chinese and German researchers has shed light on the link between groundwater balance and plant water-use efficiency in desert ecosystems, offering valuable insights for ecological restoration and combating desertification.

The study indicates that vegetation restoration in arid drylands is an effective solution for preventing desertification, according to the Northwest Institute of Eco-environment and Resources of the Chinese Academy of Sciences.

The study, a joint effort by researchers from institutions in China and Germany, was published in the journal Water Resources Research on Nov 17.

Drylands often show a negative water balance due to low rainfall and high evapotranspiration, and water becomes the main limiting factor for plant survival and growth.

"Groundwater is an important water source in desert ecosystems. The water balance of groundwater ecosystems in drylands is closely related to plant growth and determines the sustainability of ecological restoration," said Zhang Zhishan, a researcher at the Chinese institute and leader of the study.

"Groundwater is therefore crucial for ecological restoration works that are mainly based on vegetation reconstruction, as well as for desertification control efforts," he said, adding that appropriate replanting strategies play a pivotal role in preventing desertification.

The researchers conducted the study based on the automatic simulation monitoring system for water balance in the Shapotou Desert Research and Experiment Station in Northwest China's Ningxia Hui autonomous region.

The researchers used 12 lysimeter units, large-scale instruments for measuring evapotranspiration, to systematically quantify water balance components and plant growth dynamics across different desert ecosystems from 2019 to 2023.

These lysimeters were filled with wind-blown sand from the Tengger Desert and represented a range of conditions, from bare sand to plots planted with single-species shrubs and semi-shrubs, as well as mixed plantings.

The researchers then assessed plant growth performance, using water-use efficiency as the primary evaluation metric.

The study showed that groundwater recharge transformed the changes in soil water storage to a new water balance state, increasing the actual evapotranspiration and seepage. Linear mixed-effects models also showed that groundwater had a significant effect on the water balance components and enhanced plant growth performance.

Groundwater-dependent desert ecosystems exhibited higher actual evapotranspiration compared to groundwater-independent ones, according to the study.

It also highlighted that semi-shrubs play a key role in desert ecosystems with or without groundwater, providing a direct basis for the recommended plant configuration strategy for those desert ecosystems with groundwater.

"Our new study revealed that vegetation reconstruction in arid deserts is an effective solution for preventing desertification. Among which, a reasonable plant configuration method is the key to ensuring the long-term sustainability of ecological restoration and reconstruction," Zhang said.

Xinhua