摘要:城市是陆地生态系统的主要碳源，而城市植被是城市区域缓解人类活动所释放的二氧化碳的主要碳汇，但对城市植被对城市大气二氧化碳的影响方面的研究比较缺乏，尤其是发展中国家。发展中国家多数处于亚热带气候区，且发展中国家城市化进程较快，为推进不同生态系统类型碳循环的研究，该研究以位于中国东南部的上海市奉贤大学城为案例，研究该区域植被对亚热带城市生态系统CO₂通量的影响。使用上海市奉贤大学城的涡动相关通量观测站点所观测和记录的2016年10月1日至2017年9月30日共计12个月的通量，气象数据结合遥感数据分析了该研究区的CO₂通量动态特征及其影响因子，主要结论是：（1）整个生态系统全年CO₂通量总交换量为9664.06 μmol m^-2 a^-1即表现为碳源。CO₂通量增长率在2017年5月6日达到最低为-4.48 μmol m^-2 d^-1在2017年7月30日的CO₂通量增长率为0，在2017年8月30日达到最高为2.24 μmol m^-2 d^-1，生长季CO₂通量交换量为2169.58 μmol m^-2月^-1低于非生长季的CO₂通量交换量（7494.48 μmol m^-2月^-1）；（2）不同风区的CO₂通量特征不同，主要表现为随着植被面积的上升CO₂通量有下降的趋势，生长季CO₂通量均值的最低值出现在西北风区为0.09 μmol m^-2 s^-1；（3）CO₂通量与叶面积指数呈现负相关关系，即随着叶面积指数的上升CO₂通量有下降的趋势。植物的生长状况和其生理活动影响亚热带城市生态系统的碳循环过程，该研究可以为量化城市植被对大气二氧化碳的影响提供参考，同时为亚热带地区建设绿色低碳城市提供服务。



Abstract:Cities are the main carbon source among the terrestrial ecosystem types, and urban vegetation is an important carbon sink to mitigate carbon emissions from human activities in urban areas, but research on the influence of urban vegetation on urban atmospheric carbon dioxide is scarce, especially in developing countries. Most of the developing countries are in a subtropical climate zone, and the urbanization speed in developing countries is faster than that in developed countries. In order to promote the study of the carbon cycle in different ecosystem types, we studied the influence of vegetation on the CO₂ fluxes of the subtropical urban ecosystem in Fengxian University city, Shanghai, China. Using the 12-month flux observed and recorded by the eddy-related flux observation site in the study area and meteorological data combined with remote sensing data, the CO₂ flux dynamic characteristics and its influencing factors were analyzed. The main results are the following:(1) The study area was a carbon source, and the total annual CO₂ flux of the whole ecosystem was 9664.06 μmol m^-2 a^-1. The CO₂ flux growth rate reached a minimum of -4.48 μmol m^-2 d^-1 on May 6, 2017, with a CO₂ flux growth rate of 0 on July 30, 2017 and a maximum of 2.24 μmol m^-2 d^-1 on August 30, 2017. The CO₂ flux exchange in the growing season was lower than the CO₂ flux exchange in the non-growing season; these were 2169.58 μmol m^-2 月^-1 and 7494.48 μmol m^-2 月^-1 respectively; (2) Urban vegetation was a carbon sink, and its CO₂ fluxes decreased with the urban vegetation area in different wind sectors. The lowest mean value of CO₂ flux in the growing season appeared in the Northwest region and was 0.09 μmol m^-2 s^-1; (3) Leaf area index and plant biotic characteristics influence CO₂ flux. There was a negative correlation between CO₂ flux and leaf area index. Plant growth status and plant physiological activities affected the carbon cycling process of the subtropical urban ecosystem. This study can provide a reference for quantifying the effects of urban vegetation on atmospheric carbon dioxide and provide guidelines for the construction of green low-carbon cities in subtropical areas.





PDF全文下载地址:

https://www.ecologica.cn/stxb/article/pdf/stxb201801190152