ABSTRACT

The Mount Elgon ecosystem (MEE), an important hydrological and socio-economic area in East Africa, has exhibited significant landscape changes. These are driven by both natural factors and human activities. Yet, the vulnerability of this ecosystem is poorly understood. This study characterizes ecological and environmental (eco-environmental) vulnerability for the MEE using freely available Earth observation, topographic, and socio-economic data. Spatial principal component analysis (SPCA) was used to compute a new eco-environmental vulnerability index (EEVI) by integrating natural, environmental, and socio-economic conditions. The final EEVI was then categorized into five classes (potential, slight, light, moderate, and severe). Temporal principal component analysis (TPCA) was also conducted to identify persistent changes in multi-year variables spanning the period 2001–2018. Further, the precipitation concentration index (PCI) was assessed to evaluate changes in the spatio-temporal distribution of precipitation in the MEE. The study found that EEVI indicates the most aggregate vulnerability on the Ugandan side, especially in savanna regions. Majority of the MEE was moderately vulnerable, and savannas and grasslands constituted the largest proportion of the severe vulnerability class. There was also a marked increase in vulnerability with decrease in elevation. Eco-environmental vulnerability was strongly associated with multi-year variables based on precipitation, temperature, and population density. The study also found that precipitation concentration is amplifying especially in the wet season, thus threatening agriculture and community livelihoods. Areas in the moderate and severe vulnerability classes were identified for prioritized conservation attention.

摘要

埃尔贡山生态系统 (MEE) 是东非重要的水文和社会经济区，其地貌发生了显着变化。这些是由自然因素和人类活动共同驱动的。然而，人们对这个生态系统的脆弱性知之甚少。本研究使用免费提供的地球观测、地形和社会经济数据来描述 MEE 的生态和环境（生态环境）脆弱性。空间主成分分析 (SPCA) 用于通过整合自然、环境和社会经济条件来计算新的生态环境脆弱性指数 (EEVI)。然后将最终的 EEVI 分为五类（潜在、轻微、轻度、中度和重度）。还进行了时间主成分分析 (TPCA)，以确定 2001-2018 年期间多年变量的持续变化。此外，还评估了降水浓度指数 (PCI)，以评估 MEE 中降水时空分布的变化。研究发现，EEVI 表明乌干达一侧的脆弱性最为集中，尤其是在稀树草原地区。大部分生态环境为中等脆弱性，热带稀树草原和草原构成了严重脆弱性类别的最大比例。随着海拔的降低，脆弱性也显着增加。生态环境脆弱性与基于降水、温度和人口密度的多年变量密切相关。该研究还发现，降水集中度正在加剧，尤其是在雨季，从而威胁到农业和社区生计。中度和重度脆弱性等级的地区被确定为优先保护关注。