围封对高寒草甸轻度退化和沙化草地植物群落及土壤理化性质的影响OA

[Objective]This study aimed to investigate the effects of long-term enclosure on plant community structure,biomass,and soil physicochemical properties of lightly degraded and desertified alpine meadows,and to test the hypothesis that enclosure facilitates the recovery of lightly degraded meadows,but has limited restorative effects on desertified grasslands.[Method]Taking the lightly degraded and desertified alpine meadows in Nagqu,Xizang,as research subjects,the plant community structural characteristics and soil physicochemical properties inside and outside the fence were monitored after 17 years of enclosure to analyze the restoration efficacy of enclosure on grasslands with different degradation degrees.[Result]Enclosure significantly increased aboveground biomass and the importance values of Poaceae and Cyperaceae species in lightly degraded meadows.For desertified grasslands,it significantly en-hanced the Simpson and Shannon-Wiener indices but notably reduced plant community cover.Notably,no Poaceae or Cyperaceae species reappeared in the enclosed desertified meadows.Enclosure had no significant impact on soil or-ganic carbon,total nitrogen,available phosphorus,or pH in either degradation type.Aboveground biomass,vegetation cover,species richness,Shannon-Wiener index,and Margalef index were all positively correlated with soil organic car-bon and total nitrogen but negatively correlated with soil pH.[Conclusion]Enclosure effectively restores plant com-munity composition and aboveground biomass in lightly degraded meadows.However,enclosure alone is insufficient for the ecological recovery of desertified grasslands.