Remote Sensing of Land Degradation: Experiences from Latin America and the Caribbean

• Published in: Journal of environmental quality 2010-01, Vol.39 (1), p.42-61
• Main Authors: Metternicht, G, Zinck, J.A, Blanco, P.D, Valle, H.F. del
• Format: Article
• Language: English
• Subjects: Aerial photography; Agriculture; Caribbean Region; cartography; Decision trees; Deforestation; Ecosystem; environmental degradation; environmental indicators; Environmental Monitoring - methods; geographical distribution; hyperspectral imagery; image analysis; irrigation; Irrigation practices; Land degradation; Landsat; Latin America; methodology; Neural networks; new methods; overgrazing; Plants; Principal components analysis; Remote sensing; Reproducibility of Results; Salinization; Sensors; Sodium Chloride; Soil - analysis; soil degradation; Soil erosion; soil salinization; Spacecraft; spatial distribution; spectral analysis; Vegetation cover; Water; water erosion; Wind; Wind erosion
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2009.0127

Land degradation caused by deforestation, overgrazing, and inappropriate irrigation practices affects about 16% of Latin America and the Caribbean (LAC). This paper addresses issues related to the application of remote sensing technologies for the identification and mapping of land degradation features, with special attention to the LAC region. The contribution of remote sensing to mapping land degradation is analyzed from the compilation of a large set of research papers published between the 1980s and 2009, dealing with water and wind erosion, salinization, and changes of vegetation cover. The analysis undertaken found that Landsat series (MSS, TM, ETM+) are the most commonly used data source (49% of the papers report their use), followed by aerial photographs (39%), and microwave sensing (ERS, JERS-1, Radarsat) (27%). About 43% of the works analyzed use multi-scale, multi-sensor, multi-spectral approaches for mapping degraded areas, with a combination of visual interpretation and advanced image processing techniques. The use of more expensive hyperspectral and/or very high spatial resolution sensors like AVIRIS, Hyperion, SPOT-5, and IKONOS tends to be limited to small surface areas. The key issue of indicators that can directly or indirectly help recognize land degradation features in the visible, infrared, and microwave regions of the electromagnetic spectrum are discussed. Factors considered when selecting indicators for establishing land degradation baselines include, among others, the mapping scale, the spectral characteristics of the sensors, and the time of image acquisition. The validation methods used to assess the accuracy of maps produced with satellite data are discussed as well.