中文摘要：

荒漠生物结皮-土壤系统温室气体（CO2、CH4和N2O）通量数据的缺乏，给区域尺度上温室气体通量的估算带来很大的不确定性．2011-2012年在腾格里沙漠东南缘沙坡头地区不同时期建植的人工植被固沙区，采用静态箱．气相色谱法研究了不同类型和不同演替阶段生物结皮覆盖的土壤CO2、CH4和N2O的通量特征．结果表明：结皮类型、恢复时间及二者与采样时间的互作显著影响CO2通量；恢复时间、结皮类型与采样时间的互作显著影响CH4通量；采样日期显著影响CO2、CH4和N2O通量．苔藓结皮年均CO2通量（105．1mg·m-2·h-1）显著高于藻类结皮（37．7mg·m-2·h-1）．荒漠生物结皮-土壤系统年均CH4和N2O吸收通量分别为19．9和3．4μg·m-2·h-1．藻类结皮的年均CH4和N2O吸收通量略高于苔藓结皮，但差异并不显著．随着荒漠生物结皮的发育和演替的深入，生物结皮-土壤系统呼吸逐渐增加，CH4和N2O吸收能力逐渐下降．与藻类结皮相比，苔藓结皮呼吸对温、湿度的变化更为敏感，且随着生物结皮的发育和演替的深入逐渐增强．温度和湿度不是决定荒漠生物结皮-土壤CH4和N2O通量的关键因子．

英文摘要：

Uncertainties still existed for evaluating greenhouse gases fluxes （ GHGs）, including car- bon dioxide （CO2 ）, methane （CH4 ） and nitrous oxide （N2O） at the regional scale for desert eco- system because available GHGs data about biological soil crusts （BSCs） was very scarce. In 2011 and 2012, soil ecosystem covered by various types of BSCs and BSCs at different succession stages in an artificial sand-fixing vegetation region established in various periods at southeast of the Shapo- tou area in Tengger Desert was selected to measure fluxes of CO2, CH4 and N2O using static cham- ber and gas chromatography. The results showed that curst type, recovery time and their interac- tions with sampling date significantly affected CO2 flux. Recovery time and interaction of crust type and sampling date significantly affected CH4 flux. Sampling date significantly affected the fluxes of CO2, CH, and N2O. The mean annual flux of CO2 for moss crust （105.1 mg . m-2 . h-1 ） was sig- nificantly higher than that of algae crust （37.7 mg . m-2 .h-1 ） at the same succession stage. An- nual mean CH4 and N2O consumption was 19.9 and 3.4 μg . m-2 . h-1, respectively. Mean annual consumption of CH4 and N2O for algae crust was slightly higher than that of moss crust, however,significant difference was not found. Ecosystem respiration （Re） of desert soil covered by BSCs in- creased with the recovery process of desert ecosystem, in contrast, consumption of CH4 and N2O decreased. Re of moss crust was more sensitive to temperature and moisture variation than algae crust and Re sensitivity of temperature and moisture gradually increased with the development and succession of BSCs. Both soil temperature and moisture were not the main factor to determine CH4 and N2O fluxes of BSCs-soil in desert ecosystem.