干旱区生态环境知识资源中心(Arid): Continuous estimation of leaf area index and the woody-to-total area ratio of two deciduous shrub canopies using fisheye webcams in a semiarid loessial region of China

Arid

DOI	10.1016/j.ecolind.2021.107549
	Continuous estimation of leaf area index and the woody-to-total area ratio of two deciduous shrub canopies using fisheye webcams in a semiarid loessial region of China
	Niu, Xiaotao; Fan, Jun; Luo, Ruihua; Fu, Wei; Yuan, Hongyou; Du, Mengge
通讯作者	Fan, J (corresponding author), Chinese Acad Sci & Minist Water Resources, State Key Lab Soil Eros & Dryland Farming Loess P, Inst Soil & Water Conservat, Yangling 712100, Shaanxi, Peoples R China.
来源期刊	ECOLOGICAL INDICATORS
ISSN	1470-160X
EISSN	1872-7034
出版年	2021
卷号	125
英文摘要	Automatic and accurate measurements of the leaf area index (LAI) can provide information about key parameters of vegetation structure in an ecosystem. Little attention, however, has been paid to LAI dynamics for shrub canopies in both arid and semiarid regions compared to forests and crops. One of the main sources of error when measuring shrub LAI from the indirect method is the woody part. The influence of woody parts on LAI estimations can be expressed as the woody-to-total area ratio, a; there are also relatively few studies on a value of shrubs, especially the dynamic changes of a. This study used a new cost-effective tool, the fisheye webcam, to derive daily LAI and a in the fields of Caragana korshinskii and Salix psammophila on the Loess Plateau in China. The LAI data were compared with measurements acquired by an LAI-2200 Plant Canopy Analyzer and direct methods. The LAI-2200 data were consistent with the effective plant area index (PAIeff) estimated using upwardpointing webcams (UPWs) (R-2 = 0.89, root mean square error (RMSE) = 0.21) but not downward-pointing webcams (DPWs) (R-2 = 0.52, RMSE = 0.68). Shrub PAIeff derived from the DPWs was much smaller than PAIeff derived from the UPWs over the season (y = 0.48x-0.03, R-2 = 0.79, RMSE = 0.85). LAI derived from the direct methods was strongly linearly correlated with the PAI minus WAI obtained from upward digital hemispherical photography (R-2 = 0.94, RMSE = 0.62 for C. korshinskii and R-2 = 0.99, RMSE = 0.31 for S. psammophila). This result indicates that the upward digital hemispherical photography for deriving PAI and WAI performs good, which can be utilized to calculate LAI accurately. The woody-to-total area ratio (a) of deciduous shrub canopies was a dynamic parameter that varied throughout the season, decreasing as the canopy leaves developed and increasing when they fell. alpha = 1 for the leaf-off season and < 0.1 when the foliage peaked. a differed little between the two shrub canopies (R-2 = 0.95, RMSE = 0.07), and it could be used to convert PAI to LAI for C. korshinskii and S. psammophila. The UPWs demonstrated excellent potential for continuous LAI measurement for the two shrub canopies, but the DPWs should be further tested before use. The fisheye-webcam is inexpensive and can easily monitor LAI at field scale and can be used to evaluate LAI products derived from remote sensing.
英文关键词	Leaf area index Woody-to-total area ratio Fisheye webcam LAI-2200 Direct measurement Shrubs
类型	Article
语种	英语
开放获取类型	gold
收录类别	SCI-E
WOS记录号	WOS:000637785800003
WOS类目	Biodiversity Conservation ; Environmental Sciences
WOS研究方向	Biodiversity & Conservation ; Environmental Sciences & Ecology
来源机构	西北农林科技大学
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/368752
作者单位	[Niu, Xiaotao; Fan, Jun] Chinese Acad Sci & Minist Water Resources, State Key Lab Soil Eros & Dryland Farming Loess P, Inst Soil & Water Conservat, Yangling 712100, Shaanxi, Peoples R China; [Niu, Xiaotao] Univ Chinese Acad Sci, Beijing 100049, Peoples R China; [Fan, Jun; Luo, Ruihua; Fu, Wei; Yuan, Hongyou; Du, Mengge] Northwest A&F Univ, Inst Soil & Water Conservat, Yangling 712100, Shaanxi, Peoples R China
推荐引用方式 GB/T 7714	Niu, Xiaotao,Fan, Jun,Luo, Ruihua,et al. Continuous estimation of leaf area index and the woody-to-total area ratio of two deciduous shrub canopies using fisheye webcams in a semiarid loessial region of China[J]. 西北农林科技大学,2021,125.
APA	Niu, Xiaotao,Fan, Jun,Luo, Ruihua,Fu, Wei,Yuan, Hongyou,&Du, Mengge.(2021).Continuous estimation of leaf area index and the woody-to-total area ratio of two deciduous shrub canopies using fisheye webcams in a semiarid loessial region of China.ECOLOGICAL INDICATORS,125.
MLA	Niu, Xiaotao,et al."Continuous estimation of leaf area index and the woody-to-total area ratio of two deciduous shrub canopies using fisheye webcams in a semiarid loessial region of China".ECOLOGICAL INDICATORS 125(2021).