Response of the Species Diversity of Desert Riparian Forest to the Changes of Groundwater Depth in Middle Reaches of Tarim River
In this study,we collected the data from 30 plots and 30 groundwater level monitoring wells in the middle reaches of Tarim River.According to the data from monitoring wells,we divided the groundwater levels into 6 gradients:0～2 m,2～4 m,4～6 m,6～8 m,8～10 m,＞10 m.Then we analyse the coverage of vegetation and biodiversity at different groundwater levels,in order to investigate the relationship between the frequency of plants distribution and groundwater level,as well as to determine the reasonable ecological water level of the desert riparian forest in middle reaches of Tarim basin,and to provide a basis to ecosystem restoration in middle reaches even the whole basin-wide of Tarim basin.The result shows that:(1)There are 15 species in middle reaches of Tarim basin and the dominant species is Populus euphratica.(2)With the reduction of groundwater depth,the coverage of vegetation decreases gradually;As the groundwater level between 2～4 m,the average coverage is 39.14％ ;When the groundwater level between 6～8 m,the coverage of vegetation is less than 20％ ;The coverage is only 7.65％ when groundwater level less than 10 m.(3)Along with the lowering of groundwater level,the changing trend of species diversity is increased firstly,and then decreased ; The species diversity is maximum when groundwater level between 2～4 m,followed by 4～6 m and 0～2 m;When groundwater depth under 6 m,the species diversity decreases rapidly.The species diversity is precious little when groundwater level under 10 m,only P.euphratica and Tamarix chinensis still remaining.(4)Average depth of groundwater level for the species in middle reaches of Tarim river are:P.euphratica 4.58 m,T.chinensis 3.53 m,P.communis 2.34 m,Alhagi sparsifolia 4.10 m,Karelinia caspica 3.18 m,Lycium ruthenicum 2.98 m;P.communis can be suitable for the shallow level of groundwater only,the suitable water level of the rest is about 3～4 m.In summary,in the middle reaches of Tarim River,the most suitable groundwater level to the growth of plants is 2～4 m and the reasonable groundwater level to ensure the normal growth of plants is 2～6 m.It indicates that the groundwater level should be above 6 m in order to ensure the restoration of vegetation and the normal growth as well.
Gaussian regression modelspecies diversitygroundwater depthdesert riparian forestthe middle reaches of Tarim River
NETL
NSTL
万方数据
维普
