Effects of ecological water conveyance on the spatial pattern of vegetation carbon sources/sinks in the lower reaches of Tarim River [塔里木河下游生态输水对植被碳源/汇空间格局的影响]

作者：Wang C.^*; Liu Y.; Li Z.

来源：Arid Land Geography, 2021, 44(3): 729-738.

DOI：10.12118/j.issn.1000-6060.2021.03.15

• Carbon sources/sinks
• Ecological water conveyance
• Net ecosystem productivity (NEP)
• The lower reaches of Tarim River

The net ecosystem productivity (NEP) of vegetation in the lower reaches of Tarim River, Xinjiang, China from the year 2000 was estimated using data of ecological water conveyance, meteorology, land use/cover changes combined with the modified Carnegie-Ames-Stanford approach (CASA) mode and soil microbial respiration models (RH). The spatial distribution of vegetation carbon sources/sinks was analyzed, and the effect of ecological water conveyance on changes in these sources/sinks in the lower reaches of Tarim River was discussed. Results showed that (1) ecological water conveyance to the lower reaches of Tarim River since 2000 has allowed the degraded ecosystem in this area to recover to a certain extent. In addition, the vegetation carbon sinks in the area showed an increasing trend. Specifically, from 2001 to 2019, NEP showed an increase rate of 0.541 g C·m?2·a?1. The maximum increase rate, which was 0.406 g C·m?2·a?1, was observed in summer. The areas in which the carbon sinks increased were mainly located in northern Daxihaizi Reservoir, Yingsu, Bozikule Wetland, Kaldayi Wetland, and Taitma Lake. The area of vegetation carbon sinks increased by four times from 71 km2 in 2001 to 355 km2 in 2019. (2) In terms of seasonal variation, the carbon sink area measured 109 km2 in summer. Indeed, this season contributed the largest to the total carbon sink area among the four seasons, followed by spring and autumn. No obvious carbon sink areas were noted in winter. (3) Changes in the total carbon sink area of different ecosystems showed the order grassland>woodland>cultivated land>unused land>water area>construction land. The annual average change rates of the carbon sink areas in woodland and grassland, at 2.69 km2·a?1 and 3.57 km2·a?1, respectively, were higher than those of any of the other ecosystems. A good linear relationship between ecological water conveyance and carbon sink area was observed, and changes in carbon sink area indicated a lag effect of approximately 1 year.

• 单位
  中国科学院大学; 荒漠与绿洲生态国家重点实验室