Deserts take up about one fifth of the Earth's land surface.Longitudinals and dunes are the main landforms of modern deserts, classified as three types, movable deserts, fixed and semi-fixeddeserts and fixed deserts.
Vegetation is a critical biotic factor that influences the sand fixation and stability of desert ecosystems.Sand dunes can be movableor fixed, depending on the vegetation conditions.Scientists recently found that the patterns of sand dunes may have a close relationship with the status of vegetations covere, and further influence the stability of desert ecosystem.
This is a study conducted by ZHANG Yuanming and his team at the Xinjiang Institute of Ecology and Geography (XIEG) in the Gurbantunggut Desert, the largest fixed and semi-fixed desert in China.
Through investigations on the distribution of herb plants in the Gurbantunggut Desertand their relationship with environmental factors, scientists hope 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.
Their study indicated that herb species richness on the sand dunesmay have a close relation withthe slope pattern of the dunes.
“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.
This would provide a better clueto the mechanism behind desert stabilization,which is essential for developing deserts for the benefit of humankind.
The study was published with the title“Dune-scale distribution pattern of herbaceous plants and their relationship with environmental factors in a saline–alkali desert in Central Asia” inScience of the Total Environment.