Dynamic changes of transpiration water age and water utilization strategies for trees at different altitudes in Lushan area
Aims To explore the water age of dominant vegetation at different altitudes in Lushan area in the humid climate region and the strategy of water utilization for different aged sources,so as to provide scientific basis for ecological protection and resource utilization in this region.Methods Four species of Pinus(P.massoniana at low altitude,P.taiwanensis at high altitude)and Quercus(Q.variabilis at low altitude,Q.serrata at high altitude)from Lushan Mountain were studied,using stable hydrogen and oxygen isotopes technology and linear mixing water age model in order to analyze the transpiration water age of dominant vegetation at different altitudes from July 2020 to August 2021.After then,water age results and the MixSIAR source mixture model were combined to analyze the strategy of water utilization and seasonal changes.Simultaneously monitored included the air temperature and humidity,soil water content,root distribution and others.In the end,the seasonal changes of the transpiration water age and the water sources was analyzed with all the available data.Important findings(1)Plants in Lushan area mainly use the seasonal precipitation,and the age of transpiration water is between 8.67 and 16.68 d.For the same genus of species,the transpiration water age of high altitude tree species is smaller than that of low altitude.Moreover,during the observation period,the water age of P.massoniana was"single valley-shaped"and P.taiwanensis was"single peak-shaped".(2)The low-altitude tree species mainly uses shallow soil water in the early rainy season.With the going-on of rainy season,the main water-absorbing layer moves down to the deep layer,and is stabilized in the deep soil in the late rainy season.However,in the late rainy season,the high-altitude tree species mainly use the water in the middle soil level.(3)In comparison,for the low-altitude trees,their water source is less dependent on shallow(0-20 cm)soil and absorbs more of deep(60-100 cm)soil water.High altitude is on the opposite.
stable water isotopestime lag in water usespatial and temporal changes in plant water sourcesroot distribution
万方数据
维普
