The Influence of Degradation of Alpine Marshy Wetland on Ecosystem Respiration and Its Components

The degradation of alpine wetlands has become an increasingly severe problem via changing ecosystem respiration (Re) and its components, increasing carbon emissions, and affecting the carbon cycle process on Qinghai-Tibet Plateau (QTP). Currently, the responses of Re and its components to degradation succession are still unclear in alpine marshy wetland. In this study, the effects of degradation severities on Re and its components were explored in three degradation stages of alpine marshy wetland (none, light, and severe degradation) during the peak period of vegetation growth (July to August). Two methods, root separation and herbicide spraying, were used to determine respiratory components. The results showed that the degradation of alpine wetland could significantly increase Re, soil respiration (Rs) and microbial respiration (Rm). The proportion of vegetation respiration (Rv) in Re decreased significantly, while the proportion of Rm in Re increased significantly. In different degradation stages, there were differences in the relationship between components and Re. The changing ranges of temperature sensitivity indicator (Q 10 ) of Re, Rv, canopy respiration (Rvc), Rs, root respiration (Rr), and Rm were 1.41–1.50, 1.81–1.94, 4.46–6.93, 1.41–2.40, 2.84–5.97 and 1.99–3.74, respectively. Therefore, we should highlight the differential responses of the components of ecosystem respiration to warming scenarios and human disturbances to project the future carbon-climate feedback. In the future research, the herbicide spraying method can be used to measure the respiration and components of alpine marshy wetland ecosystem.