Effects Of Short-term Exclosure On Plants And Soil In Salinized Meadow In Hexi Corridor Of Northwest China

Arid regions occupy about 41%of the Earth's surface,which plays an important role in terrestrial ecosystems and has a crucial influence on ecosystem health and human survival.The establishment of nature reserve and exclosure in arid regions are effective methods to restore the vegetation degradation that caused by overgrazing.However,few studies focus on saline meadows in arid regions.In order to explain the influence of exclosure on the restoration of plant and soil,a three year enclosure experiment in an arid salinized meadow was performed in Hexi Corridor to quantify the influence of exclosure on the characteristics of dominant plants,Lycium ruthenicum Murray.(Lr)and Alhagi sparsifolia Shap.(As),as well as top-soil properties.This study not only give a better understanding of the effect of anthropogenic activity on oasis ecosystem,but also to offer some effective perspectives on local environmental protection and ecologically sustainable development.This study performed in Hexi Corridor,Gansu province.We continuously monitored the influence of exclosure on characteristics of dominant plants,Lr and As,as well as top-soil properties,by using 3-year exclosure treatment in the salinized meadow.The objectives of this study were to(1)assess the effect of exclosure on the growth of dominant plants,(2)identify the change in patterns of community structure and interspecies relationship,(3)analyze the response of plants and soil characteristics to exclosure.The key results are shown below,(1)Short term exclosure significantly increased the productivity of the salinized meadow community.The coverage,above ground biomass and plant's height in EX is significantly higher than the FG site.(2)Exclosure significantly decreased specific leaf area(SLA)and increased leaf dry matter contents(LDMC)of As,but the SLA and LDMC of Lr in EX and FG site have no significant difference,which suggest the palatability of As may be better than that of Lr,so the leaf dry weight of As in EX site was significantly increased.The N/P ratio of Lr decreased significantly after exclosure,indicating that As could keep more stable nitrogen level than Lr in the salinized meadow.(3)Exclosure reduced leaf density and proportion of thorn biomass of Lr and As obviously.In addition,As's fruit biomass distribution was significantly higher than that of Lr,Lr's stem biomass distribution was significantly higher than As,and was not affected by exclosure.(4)Exclosure significantly increased the soil Na~+and K~+contents which may due to deep soil soluble cationic moving up into topsoil with the groundwater.In conclusion,our results indicates that exclosure is beneficial to the growth and reproduction of As and Lr.As,rather Lr,is more susceptible to grazing,suggesting that As could fast recovery after exclosure.However,there was no evidence shows that the soil in this study area was getting improved after short time exclosure.Consequently,it is necessary to take a longer observation to find the effect of exclosure on characteristic of the soil.