Remote sensing observations such as normalized difference vegetation index (NDVI) trends can provide important insights into past and present land condition. However, they do not directly provide comprehensive information about our representation of land degradation and the processes at work. This study aimed to analyze vegetation productivity underlying factors in order to assess land degradation and to highlight the impact of definitions on its quantitative assessment, using Mozambique as case‐study. Land productivity change were first analyzed using NDVI time‐series (2000–2016), and a two‐step framework was then used to understand the main factors of these productivity changes. The impact of land degradation's definition was assessed based on four types of stakeholder, with different priorities in terms of ecosystem services. The results show that 25% of the country display a significant land productivity decrease, while only 3% display a land productivity increase. A large part of these land productivity changes (>61% of the decrease, and >98% of the increase) is directly assigned to human activities, such as native forest growth or tree plantations (for the increase), or forest degradation, deforestation and loss of grassland productivity (for the decrease). We showed that the fraction of degraded land varies according to stakeholders' definitions, ranging from 12% to 20% of the Country, much less than the 39% estimated by Tier 1 United Nations Convention to Combat Desertification. This study provides a sound methodological framework for assessing land degradation status that could help stakeholders to design national and locally relevant land degradation mitigation policies or programmes.

中文翻译：

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从莫桑比克的土地生产力趋势到土地退化评估：气候、人类活动和利益相关者定义的影响

归一化差异植被指数 (NDVI) 趋势等遥感观测可以提供对过去和现在土地状况的重要见解。然而，它们并没有直接提供关于我们对土地退化和工作过程的表示的全面信息。本研究旨在分析植被生产力的潜在因素，以评估土地退化并强调定义对其定量评估的影响，以莫桑比克为案例研究。首先使用 NDVI 时间序列（2000-2016）分析土地生产力变化，然后使用两步框架来了解这些生产力变化的主要因素。土地退化定义的影响是基于四种利益相关者进行评估的，在生态系统服务方面具有不同的优先级。结果表明，该国 25% 的土地生产力显着下降，而只有 3% 的土地生产力增加。这些土地生产力变化的很大一部分（下降的> 61％，增加的> 98％）直接归因于人类活动，例如原生森林生长或人工林（增加），或森林退化，森林砍伐和草地生产力的丧失（减少）。我们表明，退化土地的比例因利益相关者的定义而异，从 12% 到 20% 不等，远低于《联合国防治荒漠化公约》第 1 层估计的 39%。