干旱区生态环境知识资源中心(Arid): Identifying and understanding alternative states of dryland landscape: A hierarchical analysis of time series of fractional vegetation-soil nexuses in China's Hexi Corridor

Arid

DOI	10.1016/j.lurbplan.2021.104225
	Identifying and understanding alternative states of dryland landscape: A hierarchical analysis of time series of fractional vegetation-soil nexuses in China's Hexi Corridor
	Sun, Qiangqiang; Zhang, Ping; Jiao, Xin; Han, Wenchao; Sun, Yanan; Sun, Danfeng
通讯作者	Sun, DF (corresponding author), China Agr Univ, Coll Land Sci & Technol, Beijing, Peoples R China.
来源期刊	LANDSCAPE AND URBAN PLANNING
ISSN	0169-2046
EISSN	1872-6062
出版年	2021
卷号	215
英文摘要	Understanding and early identification of state transitions in dryland systems' landscape pattern are challenging but critical for conservation planning and sustainable management strategies. Currently the alternative states of drylands have been identified based on dynamics of single vegetation index (i.e., normalized difference vegetation index), with the interactions between vegetation and soil components often being neglected. Here, we proposed a framework for identifying the alternative states in relation to land degradation based on the interactive pathways of fractional vegetation and soil-related endmember nexuses. In this framework, we initially generated 16-day fractional green vegetation endmember (green vegetation [GV]) and soil-related endmembers (sand [SL], saline [SA], dark surface [DA]) time series using a standardized linear spectral mixture analysis model in the Hexi Corridor during 2001-2017. A discrete wavelet transform based trends and turning points detection (DWT-TTD) algorithm was proposed to detect trends, turning point types, and timing of these time series records. These metrics were subsequently used to identify eight state transition pathways for each endmember and synthetic degradation processes at the appropriate 5-10 year scale. We found that the unmixed fractional endmembers exhibited a consistent agreement with both field abundance values and estimated fractions from high-spatial-resolution Google Earth images. Based on the DWT-TTD algorithm derived alternative pathways, we found that four positive pathways of GV and DA fractions can be observed in the vegetated areas were integrated with corresponding negative pathways of SA and SL fractions. These pathways resulted in remarkably increasing GV (+4551.81 km2) and DA (+9749.26 km2) and significantly declining SA (-1452.70 km2) and SL (-9555.57 km2) from 2001 to 2017. These processes were linked to increased precipitation and temperature and reduced drought degree. Also, the timing of the turning points (around 2007 and 2013) was largely coincidental with the timing of ecological management, suggesting that ecological governance played a crucial role in the state shifts. However, because of drought trends in the barren regions, land desertification exhibited an increasing occurrence in extent (+2.5% of total pixels) during the study period, which may increase in the future, as indicated by the large pixel proportion of initially positive reversal pathway for SL (9.31%). Compared to state-of-the-art approaches, the DWT-TTD algorithm, as a multi-resolution analysis method, has the potential to detect hierarchical temporal changes and disentangle the cross-scale inherent shifts of vegetation-soil systems. The framework can help devise sustainable management practices that maintain land degradation neutrality, especially when integrated with land use cover change analysis.
英文关键词	State transition Linear spectral mixture analysis DWT-TTD algorithm MODIS Time series
类型	Article
语种	英语
收录类别	SCI-E ; SSCI
WOS记录号	WOS:000696646500005
WOS关键词	SPECTRAL MIXTURE ANALYSIS ; LAND-COVER ; MINQIN COUNTY ; CLIMATE-CHANGE ; REGIME SHIFTS ; DESERTIFICATION ; TRENDS ; DYNAMICS ; VARIABILITY ; DECOMPOSITION
WOS类目	Ecology ; Environmental Studies ; Geography ; Geography, Physical ; Regional & Urban Planning ; Urban Studies
WOS研究方向	Environmental Sciences & Ecology ; Geography ; Physical Geography ; Public Administration ; Urban Studies
来源机构	中国农业大学
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/364117
作者单位	[Sun, Qiangqiang; Zhang, Ping; Jiao, Xin; Han, Wenchao; Sun, Yanan; Sun, Danfeng] China Agr Univ, Coll Land Sci & Technol, Beijing, Peoples R China; [Sun, Qiangqiang; Sun, Danfeng] Minist Nat Resources, Key Lab Agr Land Qual, Beijing, Peoples R China
推荐引用方式 GB/T 7714	Sun, Qiangqiang,Zhang, Ping,Jiao, Xin,et al. Identifying and understanding alternative states of dryland landscape: A hierarchical analysis of time series of fractional vegetation-soil nexuses in China's Hexi Corridor[J]. 中国农业大学,2021,215.
APA	Sun, Qiangqiang,Zhang, Ping,Jiao, Xin,Han, Wenchao,Sun, Yanan,&Sun, Danfeng.(2021).Identifying and understanding alternative states of dryland landscape: A hierarchical analysis of time series of fractional vegetation-soil nexuses in China's Hexi Corridor.LANDSCAPE AND URBAN PLANNING,215.
MLA	Sun, Qiangqiang,et al."Identifying and understanding alternative states of dryland landscape: A hierarchical analysis of time series of fractional vegetation-soil nexuses in China's Hexi Corridor".LANDSCAPE AND URBAN PLANNING 215(2021).