Greenhouse gas emissions as influenced by wetland vegetation degradation along a moisture gradient on the eastern Qinghai-Tibet Plateau of North-West China

Ma, Wei; Alhassan, Abdul-Rauf Malimanga; Wang, Yuesi; Li, Guang; Wang, Hui; Zhao, Jinmei

doi:10.1007/s10705-018-9950-6

Cited by 24 publications

(6 citation statements)

References 45 publications

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“…Vegetation characteristics of the Gahai wet meadow are influenced by groundwater level, distance from the lake, composition of dominant species, vegetation cover, and aboveground biomass. In the 1950s, grazing intensity exceeded the theoretical grazing capacity of the ecosystem and led to vegetation degradation 25 , with four vegetation degradation levels commonly and widely recognized in other studies for wet meadow on the QTP 30,32 . These four degradation levels are primary wet meadow (CK), lightly degraded (LD), moderately Soil sampling.…”

Section: Experimental Design Surface Vegetation Scarcity Is the Obvimentioning

confidence: 96%

“…Studies have shown that vegetation degradation reduces the nutrient input in plant biomass, resulting in a decline in SOC and TN levels in peatlands 29 . The research on the vegetation degradation of QTP wet meadow mainly focuses on greenhouse gas emissions, microbial activity in the root area, and SOC [30][31][32] . Furthermore, several time periods are of special importance and concern for wet meadows in this region, including the spring-autumn-winter period when plant growth is slow or non-existent, and lower soil temperatures affect microbial activity 33 .…”

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confidence: 99%

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Vegetation degradation impacts soil nutrients and enzyme activities in wet meadow on the Qinghai-Tibet Plateau

Wang

et al. 2020

Sci Rep

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Vegetation degradation, due to climate change and human activities, changes the biomass, vegetation species composition, and soil nutrient input sources and thus affects soil nutrient cycling and enzyme activities. However, few studies have focused on the responses of soil nutrients and enzymes to vegetation degradation in high-altitude wet meadows. In this study, we examined the effects of vegetation degradation on soil nutrients (soil organic carbon, SOC; total nitrogen, TN; total phosphorus, TP) and enzyme activities (i.e., urease, catalase, amylase) in an alpine meadow in the eastern margin of the Qinghai-Tibet Plateau. Four different levels of degradation were defined in terms of vegetation density and composition: primary wet meadow (CK), lightly degraded (LD), moderately degraded (MD), and heavily degraded (HD). Soil samples were collected at depth intervals of 0–10, 10–20, 20–40, 40–60, 60–80, and 80–100 cm to determine soil nutrient levels and enzyme activities. The results showed that SOC, TN, catalase and amylase significantly decreased with degradation level, while TP and urease increased with degradation level (P < 0.05). Soil nutrient and enzyme activity significantly decreased with soil depth (P < 0.05), and the soil nutrient and enzyme activity exhibited obvious "surface aggregation". The activities of soil urease and catalase were strongest in spring and weakest in winter. The content of TN in spring, summer, and autumn was significantly higher than observed in winter (P < 0.05). The soil TP content increased in winter. Soil amylase activity was significantly higher in summerm than in spring, autumn, and winter (P < 0.05). TP was the main limiting factor for plant growth in the Gahai wet meadow. Values of SOC and TN were positively and significantly correlated with amylase and catalase (P < 0.05), but negatively correlated with urease (P < 0.05). These results suggest the significant role that vegetation degradation and seasonal freeze–thaw cycle play in regulating enzyme activities and nutrient availability in wet meadow soil.

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Section: Experimental Design Surface Vegetation Scarcity Is the Obvimentioning

confidence: 96%

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confidence: 99%

Vegetation degradation impacts soil nutrients and enzyme activities in wet meadow on the Qinghai-Tibet Plateau

Wang

et al. 2020

Sci Rep

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“…Each chamber collar (30 cm diameter, 55 cm height, 35 L volume) was made of PVC coupled with a PVC lid. Each chamber was placed over an area with both wetland soil and vegetation to capture total wetland carbon fluxes (Oertel et al, 2016;Ma et al, 2018). Chambers were hammered into the ground (∼1-2 cm) to ensure a complete seal.…”

Section: Co 2 and Ch 4 Flux Measurementsmentioning

confidence: 99%

Reducing Emissions From Degraded Floodplain Wetlands

Limpert

Carnell

Trevathan-Tackett

et al. 2020

Front. Environ. Sci.

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Globally, freshwater wetlands are significant carbon sinks; however, altering a wetland's hydrology can reduce its ability to sequester carbon and may lead to the release of previously stored soil carbon. Rehabilitating a wetland's water table has the potential to restore the natural process of wetland soil carbon sequestration and storage. Further, little is known about the role of microbial communities that mediate carbon cycling during wetland rehabilitation practices. Here, we examined the carbon emissions and microbial community diversity during a wetland rehabilitation process known as "environmental watering" (rewetting) in an Australian, semi-arid freshwater floodplain wetland. By monitoring carbon dioxide (CO 2 ) and methane (CH 4 ) emissions during dry and wet phases of an environmental watering event, we determined that adding water to a degraded semi-arid floodplain wetland reduces carbon emissions by 28-84%. The watering event increased anoxic levels and plant growth in the aquatic zone of the wetland, which may correlate with lower carbon emissions during and after environmental watering due to lower anaerobic microbial decomposition processes and higher CO 2 sequestration by vegetation. During the watering event, areas with higher inundation had lower CO 2 emissions (5.15 ± 2.50 g CO 2 m −2 day −1 ) compared to fringe areas surrounding the wetland (11.89 ± 4.25 g CO 2 m −2 day −1 ). CH 4 flux was inversely correlated with CO 2 emissions during inundation periods, showing a 38% (0.013 ± 0.061 g CO 2 -e m −2 day −1 ) increase when water was present in the wetland. During the dry phases of environmental watering, there was CH 4 uptake within the fringe and aquatic zones (−0.013 ± 0.063 g CO 2 -e m −2 day −1 ). A clear succession of soil microbial community was observed during the dry-wet phases of the environmental watering process. This suggests that wetland hydrology plays a large role in the microbial community structure of these wetland ecosystems, and is consequently linked to CO 2 and CH 4 emissions. Overall, the total carbon emissions (CO 2 + CH 4 ) were reduced within the wetland during and after the environmental watering event, due to increasing vegetative growth and subsequent CO 2 sequestration. We, therefore, recommend environmental watering practices in this degraded arid wetland ecosystem to improve conditions for wetland carbon sequestration and storage. Further use of this management practice may improve wetland carbon storage across other arid freshwater wetland ecosystems with similar hydrologic regimes.

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“…Water is an important factor affecting CH 4 emissions, and drying experiments have shown that lower soil water content could result in lower CH 4 emissions [66]. Moreover, studies on vegetation with different degrees of degradation (healthy vegetation, mild degradation, moderate degradation, and severe degradation) also showed that ecosystem respiration was mainly affected by temperature, while CH 4 variation was mainly determined by water content [74]. Nevertheless, experiments on moisture restoration in degraded peatlands showed that while increased water content led to increased CH 4 emissions, CO 2 emissions were reduced, resulting in a total carbon emission reduction of more than 40% [67], resulting in a carbon sink trend in the plateau.…”

Section: Whether To Consider Frozen Soil Experimental Scenario Main Imentioning

confidence: 99%

Carbon Balance of Grasslands on the Qinghai-Tibet Plateau under Future Climate Change: A Review

et al. 2020

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Climate change has brought significant impacts upon the natural ecological environment and human social development. The future carbon balance study has become an important part of research on the impacts of climate change. The Qinghai-Tibet Plateau (QTP) is a key area for studying climate change. Grassland, as a typical ecosystem of the QTP, embodies the sensitivity of the plateau to the climatic environment, so the carbon balance of grassland under future climate change conditions is important for studying global change. This paper reviewed the literature on carbon balance projection of grassland on the QTP under climate change. Two types of research methods were used to analyze and discuss the studies’ results, including experimental scenario projection and model projection. The experiment projected that appropriate temperature and moisture could enhance the carbon sink capacity of a grassland ecosystem, where moisture played a leading role. The model projection results showed that the carbon balance under different spatial and temporal scales were different. Although both can project the carbon balance of the study area, there are still some uncertainties. In addition, this research area should also consider the influence of human activity and plateau pikas to more accurately project the future carbon balance.

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Greenhouse gas emissions as influenced by wetland vegetation degradation along a moisture gradient on the eastern Qinghai-Tibet Plateau of North-West China

Cited by 24 publications

References 45 publications

Vegetation degradation impacts soil nutrients and enzyme activities in wet meadow on the Qinghai-Tibet Plateau

Vegetation degradation impacts soil nutrients and enzyme activities in wet meadow on the Qinghai-Tibet Plateau

Reducing Emissions From Degraded Floodplain Wetlands

Carbon Balance of Grasslands on the Qinghai-Tibet Plateau under Future Climate Change: A Review

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