气候变化领域集成服务门户(CCPortal): Estimating above ground biomass as an indicator of carbon storage in vegetated wetlands of the grassland biome of South Africa

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DOI	10.1016/j.jag.2019.01.021
	Estimating above ground biomass as an indicator of carbon storage in vegetated wetlands of the grassland biome of South Africa
	Naidoo L.; van Deventer H.; Ramoelo A.; Mathieu R.; Nondlazi B.; Gangat R.
发表日期	2019
ISSN	15698432
起始页码	118
结束页码	129
卷号	78
英文摘要	Wetlands store higher carbon content relative to other terrestrial ecosystems, despite the small extent they occupy. The increase in temperature and changes in rainfall pattern may negatively affect their extent and condition, and thus the process of carbon accumulation in wetlands. The introduction of the Sentinel series (S1 and S2) and WorldView space-borne sensors (WV3) have enabled monitoring of herbaceous above ground biomass (AGB) in small and narrow wetlands in semi-arid areas. The objective of this study was to assess (i) the capabilities of the high to moderate resolution sensors such as WV3, S1A and S2A in estimating herbaceous AGB of vegetated wetlands using SAR backscatter, optical reflectance bands, vegetation spectral indices (including Leaf Area Index or LAI measurements) and band ratio datasets and (ii) whether significant differences exists between the AGB ranges of wetland and surrounding dryland vegetation. A bootstrapped Random Forest modelling approach, with variable importance selection, was utilised which incorporated ground collected grass AGB for model calibration and validation. WorldView-3 (WV3) yielded the highest AGB prediction accuracies (R 2 = 0.63 and RMSE = 169.28 g/m 2 ) regardless of the incorporation of bands only, indices only or the combination of bands and indices. In general, the optical sensors yielded higher modelling accuracies (improvement in R 2 of 0.04-0.07 and RMSE of 11.48–17.28 g/m 2 ) than the single Synthetic Aperture Radar (SAR) sensor but this was marginal depending on the scenario. Incorporating Sentinel 1A (S1) dual polarisation channels and Sentinel 2A (S2) reflectance bands, in particular, yielded higher accuracies (improvement in R 2 of 0.03–0.04 and RMSE of 5.4–16.88 g/m 2 ) than the use of individual sensors alone and was also equivalent to the performance of the high resolution WV3 sensor results. Wetlands had significantly higher AGB compared to the surrounding terrestrial grassland (with a mean of about 80 g/m 2 more). Monitoring herbaceous AGB at the scale of the wetland extent in semi-arid to arid grasslands enables improved understanding of their carbon sequestration potential, the contributions to global carbon accounting policies and also serving as a proxy for functional intactness. © 2019 Elsevier B.V.
英文关键词	AGB; Carbon sequestration; Earth observation; Remote sensing; Sentinel sensors; Vegetation biomass; Wetland types
语种	英语
scopus关键词	aboveground biomass; biomass; biome; carbon sequestration; estimation method; grassland; remote sensing; sensor; vegetation dynamics; wetland; South Africa
来源期刊	International Journal of Applied Earth Observation and Geoinformation
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/156469
作者单位	Council for Scientific and Industrial Research (CSIR), Ecosystem Earth Observation, Pretoria, South Africa; University of the Witwatersrand, School of Geography, Archaeology and Environmental Studies, Private Bag 3WITS 2050, South Africa; University of Limpopo, Risk and Vulnerability Assessment Centre, Sovenga, Limpopo, Private Bag X1106, Polokwane, 0727, South Africa; University of Pretoria, Department of Geography, Geoinformatics and Meteorology, Private BagX20, Hatfield, 0028, South Africa; Scientific Services, South African National Parks, P.O. Box 787, Pretoria, 0001, South Africa
推荐引用方式 GB/T 7714	Naidoo L.,van Deventer H.,Ramoelo A.,et al. Estimating above ground biomass as an indicator of carbon storage in vegetated wetlands of the grassland biome of South Africa[J],2019,78.
APA	Naidoo L.,van Deventer H.,Ramoelo A.,Mathieu R.,Nondlazi B.,&Gangat R..(2019).Estimating above ground biomass as an indicator of carbon storage in vegetated wetlands of the grassland biome of South Africa.International Journal of Applied Earth Observation and Geoinformation,78.
MLA	Naidoo L.,et al."Estimating above ground biomass as an indicator of carbon storage in vegetated wetlands of the grassland biome of South Africa".International Journal of Applied Earth Observation and Geoinformation 78(2019).