DOI: 10.1016/j.jag.2014.08.019
Scopus记录号: 2-s2.0-84924351517
论文题名: Wavelet-based detection of bush encroachment in a savanna usingmulti-temporal aerial photographs and satellite imagery
作者: Shekede M ; D ; , Murwira A ; , Masocha M
刊名: International Journal of Applied Earth Observation and Geoinformation
ISSN: 15698432
出版年: 2015
卷: 35, 期: PB 起始页码: 209
结束页码: 216
语种: 英语
英文关键词: Bush encroachment
; Dominant scale
; Intensity
; Remote sensing
; Savanna
; Wavelet transform
Scopus关键词: abundance
; aerial photograph
; grassland
; remote sensing
; satellite data
; satellite imagery
; savanna
; spatial resolution
; woody plant
; Zimbabwe
英文摘要: Although increased woody plant abundance has been reported in tropical savannas worldwide, tech-niques for detecting the direction and magnitude of change are mostly based on visual interpretation ofhistorical aerial photography or textural analysis of multi-temporal satellite images. These techniquesare prone to human error and do not permit integration of remotely sensed data from diverse sources. Here, we integrate aerial photographs with high spatial resolution satellite imagery and use a discretewavelet transform to objectively detect the dynamics in bush encroachment at two protected Zimbab-wean savanna sites. Based on the recently introduced intensity-dominant scale approach, we test thehypotheses that: (1) the encroachment of woody patches into the surrounding grassland matrix causesa shift in the dominant scale. This shift in the dominant scale can be detected using a discrete wavelettransform regardless of whether aerial photography and satellite data are used; and (2) as the woodypatch size stabilises, woody cover tends to increase thereby triggering changes in intensity. The resultsshow that at the first site where tree patches were already established (Lake Chivero Game Reserve),between 1972 and 1984 the dominant scale of woody patches initially increased from 8 m before stabil-ising at 16 m and 32 m between 1984 and 2012 while the intensity fluctuated during the same period. Incontrast, at the second site, which was formely grass-dominated site (Kyle Game Reserve), we observedan unclear dominant scale (1972) which later becomes distinct in 1985, 1996 and 2012. Over the sameperiod, the intensity increased. Our results imply that using our approach we can detect and quantifywoody/bush patch dynamics in savanna landscapes. © 2014 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/79576
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Geography and Environmental Science, University of Zimbabwe, PO Box, MP167, Mount Pleasant, Harare, Zimbabwe
Recommended Citation:
Shekede M,D,, Murwira A,et al. Wavelet-based detection of bush encroachment in a savanna usingmulti-temporal aerial photographs and satellite imagery[J]. International Journal of Applied Earth Observation and Geoinformation,2015-01-01,35(PB)