In recent decades, land degradation has accelerated due to an increase in unsustainable human activities. In a case-study of the Andaman Islands, located in the South Asian region, changes in land degradation types, soil erosion, and the effect of conservation measures for pre- (2000) and post-2004 tsunami periods (2006, 2019) were recorded using temporal remote sensing data (LANDSAT, RESOURCESAT, CARTOSAT), field observations and a GIS-based revised universal soil loss equation (RUSLE). The results showed that erosion, leaching, acidification, salinization, and drainage congestion were the major land degradation processes that could be traced to post-tsunami human activities (R² = 0.634). The study revealed significant forest cover loss during 2006–2019 (3.76%) compared to 2000–2006 (0.61%), while it revealed increased areas under settlement (14 km²) and mining (22 km²). The annual crop area exhibited a 0.42% loss, whereas the plantation crop area increased by 0.46%, indicating the abandonment of annual crops that resulted in an increased fallow area (21 km²) during the post-tsunami period. As a consequence, degraded land increased by 2.5% of the total geographical area which was affaected by water erosion (2.3%) and chemical degradation (0.25%). The average erosion rate varied from 0.7 to 108 t ha⁻¹yr⁻¹ in 2000 but increased by 47% during the post-tsunami period due to mining, settlement, and vegetable cultivation on slopes, as indicated by high cover management, support practice, and slope length factors. Practicing suitable conservation measures can provide a conservation benefit of 105,560 t yr⁻¹ and a reduction in other forms of degradation without compromising the food production area.

中文翻译：

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南亚岛屿的海啸后土地退化：对保护优先事项的影响

近几十年来，由于不可持续的人类活动增加，土地退化加速。在位于南亚地区的安达曼群岛的案例研究中，土地退化类型的变化、土壤侵蚀以及 2004 年前（2000 年）和 2004 年海啸之后（2006 年、2019 年）的保护措施的效果是使用时间遥感数据（LANDSAT、RESOURCESAT、CARTOSAT）、实地观察和基于 GIS 的修订通用土壤流失方程 (RUSLE) 记录。结果表明，侵蚀、淋滤、酸化、盐渍化和排水堵塞是主要的土地退化过程，可追溯到海啸后人类活动（R ² = 0.634）。该研究显示，与 2000-2006 年（0.61%）相比，2006-2019 年期间森林覆盖面积显着减少（3.76%），同时还显示定居（14 km ²）和采矿（22 km ²）区域增加。一年生作物区域表现出0.42％的损失，而种植园作物面积增加了0.46％，表明一年生作物，导致增加的休耕区域（21公里的放弃²期间后的海啸期间）。因此，受水蚀 (2.3%) 和化学退化 (0.25%) 影响的总地理区域的退化土地增加了 2.5%。平均侵蚀率从 0.7 到 108 t ha ^-1 yr ^-12000 年，但在海啸后时期由于采矿、定居和斜坡蔬菜种植而增加了 47%，如高覆盖率管理、支持实践和斜坡长度因素所示。采取适当的保护措施可以提供 105,560 t yr ^-1的保护效益并减少其他形式的退化，而不会影响粮食生产区。