EPOW - Ecology Picture of the Week

Slope Stabilization in Tibet

Stabilizing Planting Grid, Sand Dune
Tibet

Explanation:  This is the high plateau of Tibet, with spectacular mountain peaks and air thin enough to induce a degree of oxygen depletion under any heavy hiking.  Just southwest of the city of Lhasa on secondary highway G318, half way to Yamtrok (Yamdrok) Lake, we are passing some immense sand dunes formed by aeolian (wind) action which continues to shift them around the landscape.  Here, the Chinese government has engaged a rather widespread and massive program to stabilize the dunes.  

In the main photo, above, the government has implanted into this dune face what seems to be a regular grid apparently intended to slow the wind erosion effect and to brace the surface, and perhaps to then serve as a template for planting shrubs and trees to further steady the slope.  This "checkerboard" protection strategy entails stabilizing the surface, then planting herbs, then shrubs (Feng et al. 2019).  

Here, shrubs have invaded, or been planted, on a dune surface containing the stabilization grid that can be seen on the left top.  

Sand dunes and desert environments are harsh environments for most (but not all) forms of life.  The seed banks are generally poor, and the soil has low fertility and moisture content (Luo et al. 2019).  To improve the environment for agricultural or other uses, stabilizing the surface is a first step.  

On less extreme slopes, the Chinese government has established plantations of poplar trees:

Across wide valley expanses, it is evident that the government is hastening to vastly change the nature of the landscape, here again with poplar tree plantations filling in bare sandy patches.  How such massive transformation of the ecosystem will affect native plant and animal species and communities may yet to be fully studied and appreciated (Liao et al. 2019).  The example below is along the Brahmaputra River floodplain between Shigatse and Lhasa.  

And here is the reason for this effort:  massive natural dunes covering entire mountain slopes, brought in and shifted about by the wind.  The sand itself may have originated from wind erosion, or perhaps by glacial till activity such as created the Great Kobuk Sand Dunes feature in northern Alaska.  If left unchecked, such conditions might spread in the process of desertification.  This is occurring in other locations in Asia, such as Inner Mongolia (Nei Mongol) of China.  

Information:
     Feng, X., J. Qu, Q. Fan, L. Tan, and Z. An. 2019. Characteristics of desertification and short-term effectiveness of differing treatments on shifting sand dune stabilization in an alpine rangeland. International Journal of Environmental Research and Public Health 16(24):4968.
     Liao, C., B. Liu, Y. Xu, Y. Li, and H. Li. 2019. Effect of topography and protecting barriers on revegetation of sandy land, Southern Tibetan Plateau. Scientific Reports 9:6501.
     Luo, J., D. Deng, L. Zhang, X. Zhu, D. chen, and J. Zhou. 2019. Soil and vegetation conditions changes following the different sand dune restoration measures on the Zoige Plateau. PLoS ONE 14(9):e0216975.