Journal Article•
Methods and Uncertainties in Evaluating the Carbon Budgets of Regional Terrestrial Ecosystems
TL;DR: In this article, the authors reviewed the observation technique systems, especially the methods and their uncertainties in evaluating regional carbon budget, and developed a multi-scale observation system comprised by field platforms, terrestrial transects and ecological networks combined with satellites and aviation observations.
Abstract: Quantitative assessment of carbon budgets at regional scale or in different ecosystems is an important scientific issue in the field of ecosystem and global change,which can provide scientific basis for forecasting climate change and regional carbon management serving for mitigation and adaptation to climate change.Though assessment and authentication of regional carbon budgets could not be fulfilled precisely using current measurements and evaluation methods,many progresses had been made.In this paper,we reviewed the observation technique systems,especially the methods and their uncertainties in evaluating regional carbon budget.To evaluate the carbon sink function of ecosystems,main industries,and projects related to carbon sink and their spatiotemporal patterns quantitatively,it is urgent to build an observation and experiment network based on field platforms and to develop a multi-scale observation system comprised by field platforms,terrestrial transects and ecological networks combined with satellites and aviation observations.The system based on observation data,ecological process model,remote sensing model and GIS spatial analysis is also needed to be built.These systems should be under the guideline of multi-scale observation,multi-method confirmation,multi-process fusion,across-scale cognition and simulation.Meanwhile,cycles of carbon,nitrogen and water in terrestrial ecosystems are coupled by various biological processes,while the knowledge of the coupling mechanisms and their influences on the spatiotemporal patterns of carbon source or sink was limited,so it will be an important aspect and new research hot in the research of ecosystem C cycle and regional carbon budget assessment and authentication.
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TL;DR: The results indicate that gross ecosystem productivity (GEP), ecosystem respiration (ER), and netcosystem productivity (NEP) of terrestrial ecosystems in China showed a significantly latitudinal pattern, declining linearly with the increase of latitude, but GEP, ER, and NEP did not present a clear longitudinal pattern.
Abstract: Understanding the dynamics and underlying mechanism of carbon exchange between terrestrial ecosystems and the atmosphere is one of the key issues in global change research. In this study, we quantified the carbon fluxes in different terrestrial ecosystems in China, and analyzed their spatial variation and environmental drivers based on the longterm observation data of ChinaFLUX sites and the published data from other flux sites in China. The results indicate that gross ecosystem productivity (GEP), ecosystem respiration (ER), and net ecosystem productivity (NEP) of terrestrial ecosystems in China showed a significantly latitudinal pattern, declining linearly with the increase of latitude. However, GEP, ER, and NEP did not present a clear longitudinal pattern. The carbon sink functional areas of terrestrial ecosystems in China were mainly located in the subtropical and temperate forests, coastal wetlands in eastern China, the temperate meadow steppe in the northeast China, and the alpine meadow in eastern edge of QinghaiTibetan Plateau. The forest ecosystems had stronger carbon sink than grassland ecosystems. The spatial patterns of GEP and ER in China were mainly determined by mean annual precipitation (MAP) and mean annual temperature (MAT), whereas the spatial variation in NEP was largely explained by MAT. The combined effects of MAT and MAP explained 79%, 62%, and 66% of the spatial variations in GEP, ER, and NEP, respectively. The GEP, ER, and NEP in different ecosystems in China exhibited ‘positive coupling correlation’ in their spatial patterns. Both ER and NEP were significantly correlated with GEP, with 68% of the per-unit GEP contributed to ER and 29% to NEP. MAT and MAP affected the spatial patterns of ER and NEP mainly by their direct effects on the spatial pattern of GEP.
254 citations
TL;DR: This study provides a new framework for global research on the interactions between carbon and water cycles as well as responses to natural and human impacts, and reveals that land-cover and land-use change in recent years has led to a decline in global WUE.
Abstract: A better understanding of ecosystem water-use efficiency (WUE) will help us improve ecosystem management for mitigation as well as adaption to global hydrological change. Here, long-term flux tower observations of productivity and evapotranspiration allow us to detect a consistent latitudinal trend in WUE, rising from the subtropics to the northern high-latitudes. The trend peaks at approximately 51°N, and then declines toward higher latitudes. These ground-based observations are consistent with global-scale estimates of WUE. Global analysis of WUE reveals existence of strong regional variations that correspond to global climate patterns. The latitudinal trends of global WUE for Earth's major plant functional types reveal two peaks in the Northern Hemisphere not detected by ground-based measurements. One peak is located at 20° ~ 30°N and the other extends a little farther north than 51°N. Finally, long-term spatiotemporal trend analysis using satellite-based remote sensing data reveals that land-cover and land-use change in recent years has led to a decline in global WUE. Our study provides a new framework for global research on the interactions between carbon and water cycles as well as responses to natural and human impacts.
182 citations
TL;DR: The results suggest that C storage in mangroves can be increased by selecting high C-density species for afforestation and stand improvement, and even more by increasing the mangrove area.
117 citations
TL;DR: The results indicate that Moso bamboo forests and products play a critical role in C sequestration, and the information gained will facilitate policy decisions concerning carbon sequestration and management of Mosoamboo forests in China.
90 citations
TL;DR: In this paper, the authors quantified the carbon exchange fluxes of different terrestrial ecosystems in the Asian region, and analyzed their spatial variation and controlling factors based on long-term observation data from ChinaFLUX (19 sites) and published data from AsiaFlux (37 sites).
89 citations
Cites background from "Methods and Uncertainties in Evalua..."
...Therefore, understanding the spatial variation and controlling mechanisms of carbon exchange fluxes between different carbon pools at global and regional scales is helpful for accurately predicting future climate change (Yu et al., 2011)....
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