荒漠草原灌丛转变过程土壤水分亏缺空间特征及影响因素OA北大核心CSTPCD

Shrub encroachment has an important impact on ecosystem structure,function and services,and its adverse impact on soil water has been recognized,but there is still a lack of quantitative assessment and research into its driving mechanisms at a regional scale.In the Ningxia desert steppe,43 paired sample sites of desert grassland and of shrubland were selected,and a'plot compared soil water deficit index'(PCSWDI)was introduced to evaluate the spatial pattern of soil water deficit and its drivers after the transition from desert steppe to shrubland.Results showed that the soil water content of 0-100 cm and 100-200 cm strata decreased significantly by 27.80%and 57.92%,respectively,after the transition from desert grassland to shrubland.Also,the PCSWDI of shrubland from 0-100 cm was significantly lower than that of desert grassland,indicating that there is no soil water deficit in the 0-100 cm layer of shrubland.Geostatistical analysis showed that the structural variance ratios of the PCSWDI of desert grassland and shrubland were 94.73%and 95.29%,respectively,which indicate strong spatial autocorrelation and were mainly controlled by structural factors.Furthermore,the geographic detector method found that soil water storage,aspect and field capacity were the dominant factors affecting the PCSWDI of the shrubland;The interactive detection showed that the spatial differentiation of the PCSWDI of the 0-100 cm soil layer of shrubland was the result of the interaction of multiple factors.In conclusion,our results show that although there was no soil water deficit in the 0-100 cm soil layer of shrubland,a significant decrease in the 100-200 cm soil water content indicating the depletion of deep soil water was observed.Therefore,vegetation restoration in arid and semi-arid regions must take into account the carrying capacity and water threshold of vegetation,and a nature-based solution may be the main focus of vegetation restoration in the future.