Deserts take up about one fifth of the Earth's land surface. As the main landforms in modern deserts worldwide, sand dunes can be movable or fixed, depending on the vegetation conditions, which is a critical biotic factor that influences the sand fixation and stability of desert ecosystems.

ZHANG Yuanming's team at the Xinjiang Institute of Ecology and Geography (XIEG) of Chinese Academy of Sciences recently conducted a study in the Gurbantunggut Desert which is the largest fixed and semi-fixed desert in China, and found that the patterns of sand dunes may have a close relationship with the status of vegetations cover, and further influence the stability of desert ecosystem.

Through investigations on the distribution of herb plants in the Gurbantunggut Desert and their relationship with environmental factors, scientists hoped to uncover the general situation of the entire desert.

Geostatistics indicated that all of the variables showed a moderate spatial dependence and obvious zonal distribution along the sand dunes. The ranges (lag distance) of density (32.2m) and coverage (33.5m) were close to the average width (31.4m) of the transects. The biomass range (74.1m) was almost equal to the average width (75m) of the sand dunes.

Analysis on the herb plant density, coverage and aboveground biomass from more than 200 sampling plots in the desert showed that the distribution of herb plants is largely dominated by the sand dune topography, soil nutrients and deep-rooted shrubbery, especially Ephedra distachya.

"Compared to large, mobile and steep sand dunes, low, fixed and gentle sand dunes contribute more to herbaceous plant abundance and distribution as well as the stability maintenance of the whole desert ecosystem,” said ZHANG.

Their study indicated that herb species richness on the sand dunes may have a close relation with the slope pattern of the dunes. This would provide a clue to the mechanism behind desert stabilization, which is essential for developing deserts for the benefit of humankind.

This study was published in Science of the Total Environment.