Spatial-temporal variation of ecosystem water use efficiency in Beijing's suburban region

• Published in: IOP conference series. Earth and environmental science 2017-08, Vol.82 (1), p.12091
• Main Authors: Mi, F, Zhang, Q, Zhang, X C, Yuan, S B, Lu, N, Yan, N Na
• Format: Article
• Language: English
• Subjects: Carbon sequestration; Coniferous forests; Deciduous forests; Drought resistance; Ecological effects; Ecosystems; Environmental regulations; Evapotranspiration; Forests; Grasslands; Remote sensing; Soil conservation; Soil water; Spatial variations; Species diversity; Temporal variations; Water conservation; Water consumption; Water shortages; Water use; Water use efficiency
• ISSN: 1755-1307; 1755-1315
• DOI: 10.1088/1755-1315/82/1/012091

Suburban ecosystem has multiple functions such as soil conservation and water regulation, which are critical for the welfare of human beings in the city. Water use efficiency (WUE) is an important indicator of ecosystem function that represents the amount of productivity per unit mass of evapotranspiration (ET). Improving WUE of suburban ecosystem is significant to climate regulation by carbon sequestration and water consumption, especially for cities with severe water shortage like Beijing, the capital of China. Based on remote sensing data, this paper examined the spatial and temporal variations in WUE in Beijing's suburban region from 2002 to 2010. The results showed that the average annual WUE was 0.868 g C mm-1 m-2. It has large spatial variation with the minimum of 0.500 g C mm-1 m-2 in the Miyun District. During the study periods, the area with significant increasing trend of WUE was 63.2% of the total suburban region. In terms of ecosystem type, the value of WUE was following the sequence, deciduous coniferous forest (0.921g C mm-1 m-2) > mixed forest (0.887g C mm-1 m-2) > deciduous broadleaf forest (0.884 g C mm-1 m-2) > shrubland (0.860 g C mm-1 m-2) > evergreen coniferous forest (0.836 g C mm-1 m-2) > grassland (0.830 g C mm-1 m-2). As ET was similar among the ecosystems, the difference in WUE was mainly due to the discrepancy of NPP. We found that NPP significantly correlated with the diversity of ecosystem type (represented by Shannon-Wiener index). Our results suggest that ecological engineering construction, scientific ecosystem type selection, ecosystem diversity improvement and drought-resistant species cultivation are conductive to improve ecosystem WUE in Beijing's suburban region.