城市土地覆被变化对微尺度上土壤呼吸的影响
文献类型：学位论文
| 作者 | 武小钢 |
| 学位类别 | 博士后 |
| 答辩日期 | 2014-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 胡聃 |
| 关键词 | 城市 人工构筑物 土壤呼吸 时空变异 urban man-made structures soil respiration temporal and spatial variation |
| 学位专业 | 生物学 |
| 中文摘要 | 土壤呼吸过程对环境变化的响应及其时空变异性，是全球气候变化研究所面临的主要 挑战。测定不同陆地生态系统土壤呼吸速率及其时空波动，阐明其影响因子，对于全球碳 平衡和全球变化潜在效应估计是最为基本的数据。过去的研究大大促进了我们对土壤呼吸 过程机制的理解，但是相对于其他陆地生态系统，由人类活动主导的城市化过程所驱动的 剧烈环境变化下城市土壤呼吸研究案例还十分缺乏。 人工构筑物和人工植被群落是城市区别于自然生态系统的典型特征，也是城市多种生 态过程发生改变的重要根源，研究这两种广泛而剧烈的变化对城市系统中关键生态过程， 如土壤碳循环的影响及其机理，对于提高我们对城市生态系统的理解，进而在城市规划、 布局、建设以及管理等活动中采取行之有效的措施具有重要价值。基于此，本项目对人工 构筑物邻接绿地和人工植被群落土壤呼吸的时间和空间分布特征进行观测，探讨两个方面 的问题。一是城市人工构筑物对邻接绿地土壤呼吸的影响如何，其影响范围和程度有多大， 是否存在规律性的变化格局？二是城市人工植被群落土壤呼吸的时空动态及其控制因子。 结果表明： 1) 城市人工构筑物对邻接绿地土壤呼吸具有显著影响，近构筑物处土壤 呼吸速率显著高于远端，随着距离梯度增加土壤呼吸速率呈线性递减趋势；2) 人工构筑物 对邻接绿地土壤温度和水分具有显著影响，进而影响土壤呼吸速率，土壤呼吸与土壤温度 正相关，而与土壤水分负相关；3) 人工构筑物对邻接绿地土壤呼吸的影响在日尺度上表现 为单峰曲线，气温较高的时段土壤呼吸速率较大，且影响范围也更大；4) 人工构筑物体量 （面积、宽度、高度等）、距离与土壤呼吸速率具有显著正相关性，二者的交互作用可对土 壤呼吸速率产生显著影响；5) 城市人工植被群落内土壤呼吸具有明显的季节差异，其主要 受到温度的控制，二者呈指数分布，相关系数0.907（p<0.01）；6) 人工植被群落内土壤呼 吸具有较高的空间变异，生长季节内空间变异主要受到结构性因子的影响，空间自相关的 尺度范围为7.25-9.05m；休眠季节土壤呼吸空间变异完全由随机因素引发；7) 影响生长季 节土壤呼吸空间变异的因素有土壤温度、土壤水分含量、硝态氮含量、硫含量、叶面积指 数、根系生物量、测定点6m 半径内林木平均胸径以及株数，其中叶面积指数、土壤水分 含量和硫含量为主要控制因素。 |
| 英文摘要 | Soil respiration is one of the largest CO2 fluxes in the global carbon cycle, and plays an important role in regulating the feedbacks between terrestrial ecosystems and the atmosphere.Our ability to predict this flux remains limited because of multiple controlling mechanisms that interact over different temporal and spatial scales. Understanding the relationship of soil respiration to its influencing factors and the variable pattern of soil respiration in both time and space, remains a key objective for research into ecosystem C cycling and biosphere-atmosphere interactions. Previous studies have greatly improved our understanding about the mechanism of soil respiration. However, there is little information on the effects of urbanization on soil respiration in urban ecosystem. Artificial structures and artificial vegetation community are the typical characteristics of city differed from natural ecosystems, also a major source of various changes occurred in ecological processes in city. The study of effect and mechanism of these two broad and dramatic changes in the urban on key ecological processes, such as soil carbon cycle, is valuable for improving our understanding of the urban ecosystem, and then take effective measures in urban planning, layout, construction and other management activities. The objectives of this study were to (1)identify the scope and extent of influence of artificial structures on soil respiration in the adjacent green space; (2) investigate the temporal and spatial variation in soil respiration and evaluate theimportance of stand structure, soil physic-chemical parameters, and fine root for observed difference in soil CO2 efflux rates within sites and seasons in city green space. The results showed that: 1) urban artificial structures have a significant impact on the soil respiration of adjacent green space, the soil respiration rate declined as the distance increases; 2) artificial structures have a significant impact on the temperature and moisture of adjacent soil, thereby affecting soil respiration , soil respiration positive correlated with soil temperature, but negatively correlated with soil moisture; 3) the diurnal change of soil respiration showed a single peak curve; 4) artificial structures body mass ( size , width, height , etc. ) and distance have significant impact on soil respiration rate; 5) soil respiration in urban plantation showed an obvious seasonal change, which mainly affected by temperature (r2=0.907, p <0.01); 6) there is high spatial variability in the soil respiration of urban plantation during the growing season, which mainly affected by structural factors, but random factors during the dormant season; 7) the control factors of spatial variation included soil temperature, soil moisture content , nitrate content , sulfur content, leaf area index , root biomass , number of trees and average DBH within 6m radius of measurement point. |
| 公开日期 | 2015-07-07 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/15610]  |
| 专题 | 生态环境研究中心_城市与区域生态国家重点实验室 |
| 推荐引用方式 GB/T 7714 | 武小钢. 城市土地覆被变化对微尺度上土壤呼吸的影响[D]. 北京. 中国科学院研究生院. 2014. |
入库方式： OAI收割
来源：生态环境研究中心
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