Study Of Rainfall Redistribution Characteristics Of Typical Scrubs At The Eastern Foot Of The Helan Mountains

The Helan Mountains are located in the arid and semi-arid region of northwest China,Drought and low rainfall have led to patchy distribution of scrub at low elevations,water scarcity has become a major limiting factor for scrubs recovery at low elevations of the Helan Mountains,the study of the effect of scrubs on rainfall redistribution patterns in this region is important for vegetation restoration.The experiment was carried out between May and September 2022,using field observations and statistical analysis of the data collected.The rainfall redistribution process of Salsola laricifolia,Prunus mongolica,Caragana stenophylla,Rosaxanthina,Caragana opulens and Spiraea mongolica was studied.The rainfall redistribution patterns of typical scrub were measured and analysed,and the effects of rainfall characteristics,canopy structural characteristics of the scrub and meteorological factors on the rainfall redistribution characteristics of the six typical scrubs were analysed.The main findings are as follows:(1)Twenty-two rainfall events were recorded during the experiment,with a cumulative rainfall of 178.6 mm,mainly dominated by low rainfall events with rainfall(P)<5 mm,accounting for more than half of the total rainfall events.There were significant differences between the throughfall,stemflow and interception characteristics of the six typical scrubs,but the variability between the rainfall redistribution characteristics of the six typical scrubs decreases with increasing rainfall.(2)Among the six typical scrubs,the highest throughfall rate was 79.51%in the R.xanthina and the lowest was 75.67%in C.stenophylla;the highest stem flow rate was 9.30%in C.slenophylla and the lowest was 2.89%in P.mongolica;the highest canopy retention rate was 1 7.68%in both the P.mongolica and S.mongolica,and the lowest was 14.12%in C.stenophylla.The smallest canopy retention rate was 14.12%for R.xanthina.There were significant positive correlations(P<0.05)between throughfall.throufall rate,stem flow rate and rainfall pooling rate and rainfall intensity,and significant positive correlations(P<0.05)between canopy retention and canopy retention rate and rainfall amount and negative correlations(P<0.05)with rainfall intensity for the six typical thickets.(3)Correlation analysis between canopy structural characteristics of the scrub and rainfall redistribution patterns of the scrub showed a correlation between canopy morphological characteristics and rainfall redistribution characteristics.Morphological characteristics of the scrub had an effect on throughfall,but the effect varied between shrubs.There were significant correlations between the number of branches,canopy thickness and canopy area of P.mongolica and S.mongolica and rainfall redistribution characteristics.(4)There was a correlation between rainfall redistribution characteristics and meteorological elements in the six typical scrubs,and this experiment found that it was mainly the mean humidity that influenced the canopy interception process of rainfall redistribution,and thus the overall canopy rainfall redistribution pattern.There was a significant positive correlation(P<0.05)between stem flow rate and mean humidity for S.laricifolia,P.mongolica,C.stenophylla and C.opulens scrubs,and between canopy retention and mean humidity for Spiraea mongolica scrubs,and a significant negative correlation(P<0.05)between canopy retention and mean humidity for S.laricifolia,C.stenophylla and S.mongolica scrubs.In summary,this study has conducted a systematic study on the rainfall redistribution characteristics of six scrubs in the eastern Helan Mountains.providing data support and reference for improving the understanding of the rainfall redistribution process of scrub plants in the low elevations areas of the eastern Helan Mountains and key technologies for the restoration of irrigation-free vegetation in the the low elevations areas of the eastern Helan Mountains,which is important for ecological security,vegetation restoration and high-quality sustainable development of the ecological environment in the eastern Helan Mountains.