黑河下游绿洲植被优势种生物量空间分布及蒸腾耗水估算

Biomass-based Transpiration Water Consumption of Dominant Species of Vegetation Estimation in the Oasis of Lower Reaches of Heihe River

基于典型样点试验,建立了研究区植被优势种柽柳、胡杨与苦豆子地上生物量与其生态参数关系模型;利用高分辨率遥感影像Geoeye-1对植被优势种进行分类得到生态参数,实现了其地上部分生物量空间分布估算;最后利用生物量与蒸腾系数关系,估算植被优势种蒸腾耗水。结果显示:植被优势种总生物量为2.53×106t,河流距离对生物量影响显著。根据试验测得的植被优势种蒸腾系数估算出总蒸腾耗水量为10.89×108t,柽柳、胡杨与苦豆子所占比例分别为12.94%,82.93%与4.13%。

The research object of this study are the Tamarix ramosissima, Populus euphratica and Sophora which are the dominant species vegetation in lower reaches of Heihe River. Guided by the theories of Ecology Hydrology, Geobotany, Statistics theories and other disciplines, field investigation combined with remote sens- ing and spatial analysis methods were applied to study biomass and transpiration water consumption of domi- nant species of vegetation in study area. Firstly, biological characteristics of typical samples survey and bio- mass observation of dominant species of vegetation was made. The relational model of aboveground biomass and the ecological parameters （canopy area or coverage area） of dominant species of vegetation were construct- ed. Then, ecological parameters of dominant species of vegetation were obtained from high resolution satellite imagery Geoeye-1 which were classified by decision tree method to realize the spatial distribution estimation of aboveground biomass of dominant species of vegetation. Finally, the transpiration water consumption of dominant species of vegetation was estimated by the relationship between biomass and transpiration coeffi- cient. According to the studying results, the spatial distribution characteristics of aboveground biomass and transpiration water consumption of 0-2 km, 2-5 km, 5-10 km and 10-15 km river buffer zone were analyzed. The spatial distribution pattern of transpiration water consumption was revealed. The following results were gotten. According to the classification result, the total canopy area of Tamarix ramosissima and Populus euphrat- ica are 2.44× 10^2 km^2 and 3.61 × 10 km^2 respectively. And the coverage area of Sophora alopecuroides is 4.28 ×10^2 km^2. The total biomass of dominant species of vegetation was 2.53 × 10^6 t. The distance to river on the biomass of dominant species of vegetation is significant. According to the experimental results of the transpiration coef- ficient of dominant species of vegetation. The total transpiration water consumption of dominant species of vegetation is 10.89 × 10^8 t. The propotion of Tamarix ramosissima, Populus euphratica and Sophora alopecuroides are 12.94%, 82.93% and 4.13% respectively.