Winter snowfall is an important water resource for organisms in desert ecosystems. Biological soil crust (BSC) is the most representative functional vegetation unit in desert ecosystem, and the change of snowfall depth has potential influence on the development and ecological function of BSC. However, researches on this potential influence have received very little attention. 

Researchers from the Northwest Institute of Eco-Environment and Resources of the Chinese Academy of Sciences (CAS) conducted a field snow simulation experiment to measure the water content, nutrient concentrations and microbial biomass under snow cover of different depths in the Gurbantunggut Desert of Northwest China. 

In this study, the researchers found that water content increased with increasing snow depth (P < 0.05). Snow removal and snow cover reduction decreased nutrient and microbial biomass concentrations in both biocrust types (P < 0.05). The concentrations of most measured nutrients and microbial biomass decreased significantly when snow depth was increased to twice ambient conditions (P < 0.05).  

Research results indicate that changes in snowfall depth (increasing or decreasing snowfall depth) have significant adverse effects on carbon and nutrient availability of BSC as well as microbial inventory. This pattern of adverse effects may make the arid desert, which is already barren, more deficient in nutrients or less fertile. 

In addition, the BSCs and their interaction with snowfall depth can influence the carbon and nutrient availability as well as microbial biomass of BSCs, and the existence of interaction means that crusts can regulate the impact of snowfall change. The study shows that the concentrations of nutrients and microbial biomass were significantly influenced by snow depth (P < 0.05), crust type (P < 0.001), and their interaction (P < 0.05). 

These findings have demonstrated that both snow reduction (especially snow removal) and substantial increase (2.0S) in this region seemed to negatively influence carbon and nutrient availability and microbial biomass after four years of snow manipulation. Therefore, based on the background of global climate change, such changes might lead to a cascading effect in species composition and function of BSC communities in arid regions.  

Moreover, these results imply that crust type may regulate the effect of change in snow depth on complexes of biological soil crusts and subcrust soil. Therefore, It is particularly important to further evaluate the development and ecological function of BSC in arid and semi-arid desert areas in response to the adverse effects of snowfall change. 

This study has been published in Geoderma in an article entitled “Effect of snow cover on water content, carbon and nutrient availability, and microbial biomass in complexes of biological soil crusts and subcrust soil in the desert”. 

Contact: 

HUI Rong 

E-mail: huirong@lzb.ac.cn 

Shapotou Desert Research and Experiment Station, The Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences