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

Abstract

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.

Evaluating Biophysical Attributes of Environmentally Degraded Landscapes in Northern Ethiopia using LANDSAT ETM data and GIS

“…Consequently, settlement areas were delineated on the topographic map and added to the classified image. Despite these limitations, LANDSAT ETM+ data has distinguished the major land cover types, which is consistent with the capability of LANDSAT ETM data demonstrated elsewhere for mapping and monitoring land cover of environmentally degraded landscapes (Metternicht et al;2009;Lu et al;and Zhang et al;.…”

“…Several studies have implemented remote sensing tools for mapping and monitoring land use land cover of degraded landscapes (Metternicht et al;2009;Lu et al;Zhang et al;2005 and Reina et al;1991). Raina et al (1991) used LANDSAT TM to map the types, extents and degrees of land degradation in an arid region of Jodhpur in India, while Lu et al (2007) mapped and monitored environmental degradation and dynamics in western Brazilian Amazon using multi-temporal LANDSAT TM/ETM data.…”

The role of Remote Sensing in land degradation assessments: opportunities and challenges

“…Even with the existing demand for LD-related spatial information, there is still no global agreement on the definition of LD and standardized methodology for its assessment at different spatial scales, while the reliability of the existing maps is often questioned (Higginbottom & Symeonakis, 2014;Metternicht, Zinck, Blanco, & Del Valle, 2010). The reasons behind are the differences in definition of LD, methods for LD mapping and field data scarcity.…”

Early Identification of Land Degradation Hotspots in Complex Bio-Geographic Regions

“…Currently, medium resolution multispectral satellites, particularly the Landsat series, still represent the main data source used for land degradation assessments over large regions and long term periods, especially where no information is available on the specific causes of degradation (e.g., [28,46,47]). Many studies using Landsat TM and ETM+ data have focused on drylands and on soil processes such as erosion and crusting [46,[48][49][50][51].…”