Analysis of organic carbon sink increment and management in Uxin Banner, Inner Mongolia, China
Modifications of land surface through human activity have become an important factor affecting the global carbon cycle.Land surface changes can result in the release of carbon from terrestrial ecosystems.Additionally,through reasonable land use and management,land surface alterations can also serve to increase carbon sinks.In dryland ecosystems,which occupy 30％-40％ of Earth's land surface and play an important role in the global carbon cycle,harsh natural conditions combined with frequent human activities release carbon stored in the ‘ plant-soil’ continuum as CO2 into the atmosphere.Given the increased rates of desertification due to climate change,the expansion of arid land surfaces may have a profound impact on the global carbon balance.Therefore,we selected Uxin Banner (equal to county),located in Mu Us Sandy Land,Inner Mongolia,China,as a case study.To assess the increment of organic carbon sinks and the management regulations for arid land,we classified six vegetation categories and 16 sub-categories using cloud-free Landsat images across five decades (1977,1987,1997,2007,and 2012) using ArcGIS 10.0.Carbon density,including aboveground organic carbon,belowground organic carbon,and soil organic carbon,was also analyzed for each category.Combining vegetation maps and carbon densitydata,we analyzed organic carbon storage using Cellular Automata-Markov model implemented in InVEST software package to develop different scenarios of carbon sink increment of this area.(1) The results showed that during the 35 years,from 1977 to 2012,carbon storage in Uxin Banner averaged at 47.38 Tg C.Patterns revealed that carbon decreased by 1.69 Tg C from 1977 to 1997 and carbon storage increased by 0.77 Tg C from 1997 to 2012.These patterns are similar to those of desertification,where changes in climate coupled with human influence enhanced recovery of vegetation in the region,thereby increasing the carbon sink.(2) The results from the scenario analysis indicate that the potential for carbon sink increment in Uxin Banner is relatively large if effective regulatory approaches,such as increasing the forest vegetation coverage,transferring land use patterns,and wetland conservation,are applied.According to the policy scenario,terrestrial ecosystem carbon stocks of Uxin would increase by 3.83 Tg C compared to those in 2012.Given the dry and rainless climate in the region,drought-tolerant shrubs and indigenous shrubs should be selected in the project for sand fixation and afforestation to reduce the consumption of region's ecological water.According to four desertification scenarios,changes in land use patterns are feasible ways to increase carbon sinks.After stabilization of mobile and semi-fixed sand land,organic carbon pool might increase by 6.98 Tg C compared to the levels in 2012.Changes in land use practice,such as enclosing grassland,forbidding open grazing,extending artificial grassland,and drylot feeding,might help to reduce grazing pressure on grasslands and enhance carbon sink function.Wetland is one of the major vegetation types involved in carbon sequestration in Uxin,which has higher grazing utilization by herdsmen.For the protection of wetland,government should establish regulatory approaches to promote wetland area recovery such as limiting grazing intensity,affording ecological compensation,and establishing reasonable water use of the wetland area.The present research,using scientific output,provides recommendations to encourage balancing between protection of the natural environment and the development of social economy through regulatory approaches and measures suitable for the increment of carbon sinks.
国家科技期刊平台
NSTL
万方数据
维普
