Coexistence patterns of biocrust-vascular plant in the Loess Plateau

Biological soil crust (biocrust) widely distributes in the Loess Plateau, which is the most typical loess platform worldwide, and a cultural origin of China. Since 1999, the Loess Plateau experienced heavily restorations, costed hundreds of billions Chinese Yuan. Even so, we have no clear idea of how do major biological components – biocrust, grass, and shrub coexist together therein, which can greatly affect restoration practices. To that end, this study combined field survey, reference compiling and remote sensing data to identify coexistence patterns of biocrusts and vascular plants (grass and shrub) on the Loess Plateau. A total of 262 data points had been collected. We found that precipitation, surface temperature and solar radiation were the major drivers in the Loess Plateau, and there were three coexistence patterns, namely high biocrust-vascular mixed state under high annual rainfall and surface temperature of 10-12°C, biocrust-dominated state under low rainfall condition and low biocrust-vascular mixed state under low surface temperature situation. Furthermore, we found that high biocrust-vascular mixed and biocrust-dominated states appeared to be alternative states along annual rainfall gradient. This study discovered coexistence patterns of biocrust-vascular plant in the Loess Plateau for the first time, and can guide future restoration and conservation in the region. This is crucial for achieving sustainable development and ecological safety of north China.