DOI: 10.1111/gcb.13529
论文题名: Woodland expansion in South African grassy biomes based on satellite observations (1990–2013): general patterns and potential drivers
作者: Skowno A.L. ; Thompson M.W. ; Hiestermann J. ; Ripley B. ; West A.G. ; Bond W.J.
刊名: Global Change Biology
出版年: 2017
卷: 23, 期: 6 起始页码: 2358
结束页码: 2369
语种: 英语
英文关键词: bush encroachment
; grassland
; land-cover change
; Landsat
; savanna
; South Africa
; synthetic aperture radar
; woodland expansion
Scopus关键词: Elephantidae
英文摘要: Increases in woody plant cover in savanna grassland environments have been reported on globally for over 50 years and are generally perceived as a threat to rangeland productivity and biodiversity. Despite this, few attempts have been made to estimate the extent of woodland increase at a national scale, principally due to technical constraints such as availability of appropriate remote sensing products. In this study, we aimed to measure the extent to which woodlands have replaced grasslands in South Africa's grassy biomes. We use multiseason Landsat data in conjunction with satellite L-band radar backscatter data to estimate the extent of woodlands and grasslands in 1990 and 2013. The method employed allows for a unique, nationwide measurement of transitions between grassland and woodland classes in recent decades. We estimate that during the 23-year study period, woodlands have replaced grasslands over ~57 000 km2 and conversely that grasslands have replaced woodlands over ~30 000 km2, a net increase in the extent of woodland of ~27 000 km2 and an annual increase of 0.22%. The changes varied markedly across the country; areas receiving over 500 mm mean annual precipitation showed higher rates of woodland expansion than regions receiving <500 mm (0.31% yr−1 and 0.11% yr−1, respectively). Protected areas with elephants showed clear loss of woodlands (−0.43% yr−1), while commercial rangelands and traditional rangelands showed increases in woodland extent (>0.19% yr−1). The woodland change map presented here provides a unique opportunity to test the numerous models of woody plant encroachment at a national/regional scale. © 2016 John Wiley & Sons Ltd 资助项目: Skowno, A.L.
; Rhodes UniversitySouth Africa
; 电子邮件: A.Skowno@sanbi.org.za
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/60935
Appears in Collections: 影响、适应和脆弱性
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作者单位: Rhodes University, Grahamstown, South Africa; South African National Biodiversity Institute, Cape Town, South Africa; Geo Terra Image (Pty Ltd), Pretoria, South Africa; University of Cape Town, Rondebosch, South Africa; South African Environmental Observation Network, Pretoria, South Africa
Recommended Citation:
Skowno A.L.,Thompson M.W.,Hiestermann J.,et al. Woodland expansion in South African grassy biomes based on satellite observations (1990–2013): general patterns and potential drivers[J]. Global Change Biology,2017-01-01,23(6)