Effects of Simulated Warming and Snow Addition on Plant Community and Soil Nutrient in Alpine Meadow
Taking the alpine meadow plant community at the surrounding Namtso Lake in central Tibet Autono-mous Region as the study object,the effect of climate change on alpine meadow plant community structure,diver-sity and soil nutrients were analysed with Open-Top Chambers(OTCs)treatment simulating warming(Wa)and snow addition(S)treatment as a simulation of early spring snow disaster.The plant community evenness under Wa and warmig+snow addition(SWa)treatments was significantly higher than that in control(C)but it was lower under S treatment.There were no significant differences in Simpson,Shannon-Wiener and Margalef index be-tween treatments.The importance value of dominant species(Carex parvula)was significantly lower under the Wa and SWa treatments than control group.Vegetation coverage was significantly lower under Wa treatment than that in C,S and SWa groups.The vegetation+snow addition height under all three treatments mentioned above was higher than that in control group,among which it was significantly higher under the SWa treatment than that in control group.The effect of different treatments on soil nutrients did not reach to significant level.Correlation analysis showed that vegetation coverage was positively correlated with organic carbon(OC),soil mois-ture content(SMC)and hydrolysable nitrogen(HN)significantly under Wa treatment,but average vegetation height and Shannon-Weiner index were positively correlated with soil pH significantly.Under SWa treatment,the mean height of plant community and Margalef index were negatively correlated with SMC significantly,and the mean height was positively correlated with soil pH significantly,the Margalef index was positively correlated with available phosphorus(AP)significantly.There was a significant positive correlation between Pileous index and AP under S treatment.Margalef index was negatively correlated with OC and HN significantly in control group.The results of this study revealed the response of alpine meadow plant community and soil nutrient to cli-mate change,and provided a scientific basis for further study of the alpine grassland ecosystems cope with cli-mate change in Tibet.