三峡库区城镇河流凋落物分解对城镇化率的响应  

Response of leaf-litter decomposition in urban streams of the Three Gorges Reservoir area to different urbanization rates

作　　者：王程成 韦冰 姚婧梅[1] 林敦梅[1] 何强[1] 钱深华 智悦[1] 韩乐[1] 邓连森 谭秋君 WANG Chengcheng;WEI Bing;YAO Jingmei;LIN Dunmei;HE Qiang;QIAN Shenhua;ZHI Yue;HAN Le;DENG Liansen;TAN Qiujun(Key Laboratory of the Three Gorges Reservoir Region′s Eco-Environment,Ministry of Education,Chongqing University,Chongqing 400044,China)

机构地区：[1]重庆大学三峡库区生态环境教育部重点实验室,重庆400044

出　　处：《生态学报》2025年第6期2905-2917,共13页Acta Ecologica Sinica

基　　金：国家自然科学基金(U20A20326);中央高校项目(2019CDXYCH0026);重庆市留学人员创新支持计划(cx2021107)。

摘　　要：凋落物分解对河流生态系统的养分循环具有重要意义,但城镇化对河流凋落物分解的影响机制有待揭示。为探明不同城镇化率河流凋落物分解规律及分解者类群相对贡献的变化,以3条不同城镇化率的三峡库区典型城镇河流为研究地,选取2种不同初始理化性质的河岸带常见凋落叶,原位设置2种孔径(0.05mm和1mm)的分解袋开展实验。结果表明:(1)高城镇化河流中凋落物分解速率下降了约30%(构树与小叶榕分别下降了约1/4和1/3),难分解树种小叶榕的下降更显著;(2)分解者群落中微生物在城镇河流中均占80%以上的主要贡献;高城镇化率河流中细菌分解者的相对贡献大于真菌,底栖动物中耐污种占比上升至90%,对分解起主要作用的撕食者消失,对易分解和难分解树种的相对贡献分别下降了45%与15%。凋落物分解速率在中低城镇化率河流无明显改变,在高城镇化率河流中显著降低。为阐明亚热带城镇河流凋落物分解的退化机制提供了科学依据。The leaf-litter decomposition is crucial for nutrient cycling in aquatic ecosystem,but the impact of urbanization on leaf-litter decomposition in urban streams remains to be clarified.To explore the transformation of relative contribution among leaf-litter decomposer groups and decomposition of streams with different urbanization rates,we took 3 Three Gorges Reservoir Regional urban streams with different urbanization rates as the research site,2 representative leaf-litter in riparian zones with different initial physiochemical properties were selected,and decomposition bags with 2 different mesh sizes(0.05mm and 1mm)were set in situ to carry out the experiment.The results showed that:(1)The decomposition rate of leaf-litter decreased by approx 30%in the high urbanization rate stream(the average decomposition rate of Broussonetia papyrifera and Ficus microcarpa decreased by 1/4 and 1/3),the decline of recalcitrant leaf-litter was more significant.(2)Microbial decomposers contributed over 80%to the leaf-litter breakdown across all the three streams.In the stream with high urbanization rate,the relative contribution of bacteria decomposition is greater than that of fungi;The proportion of pollution tolerant species in benthic invertebrates increased to 90%,and the shredder who played a vital role in decomposition disappeared,and the relative contribution to less recalcitrant leaf-litter and recalcitrant leaf-litter decreased by 45%and 15%.The decomposition rate did not change significantly in streams with low and medium urbanization rate,but was significantly reduced in stream with high urbanization rate.This study provided a scientific basis for elucidating the degradation mechanism behind stream leaf-litter decomposition in subtropical towns.

关 键 词：凋落物分解 城镇化 河流 底栖动物 微生物 三峡库区 

分 类 号：F29[经济管理—国民经济]