Multi-temporal analysis of land cover dynamics using remote sensing can enable the determination of the spatial extent and average rate of land cover change. With the application of an appropriate change analysis method, it is also possible to distinguish whether a land cover change has occurred by the effect of a random or a systematic process. In connection with this, characterizing rainfall variability and historical meteorological drought events can allow understanding of their effects on agro-ecosystems and vegetation cover dynamics. Therefore, this study has evaluated multi-temporal land cover change in response to the possible impacts of population pressure and rainfall variability on agro-ecosystem dynamics. This was conducted on a traditional agroforestry-dominated landscape in Southern Ethiopia. Using Landsat images acquired in 1985, 2000, and 2018, a post-classification land cover change analysis approach was employed to distinguish between a systematic and random process of inter-category transitions. Assessment of drought events and rainfall variability dynamics were performed using standardized precipitation index (SPI) and rainfall coefficient of variation (CV), respectively. Mann–Kendall test was also applied for the detection of a monotonic rainfall trend. A bias-corrected Climate Hazards group Infrared Precipitation with Stations (CHIRPS) over 1981–2017 was used to calculate the SPI, CV and Mann–Kendall trend test. The analysis showed that above 41% of the landscape has experienced land cover transitions between 1985 and 2018. This has primarily resulted by a systematic and rapid expansion of agriculture, urban areas, and eucalyptus plantations, at the expense of natural vegetation ecosystems. Consequently, over the last 33 years (1985–2018), natural forest, grassland, and wetland have declined by 74.8%, 83.3%, and 78.4%, respectively. Another major land cover change identified in this study was the replacement of open-field crops by agroforestry, mainly in the western part of the catchment. Such expansion of agroforestry has appeared to be spatially correlated with a lower amount of long-term average and more variable rainfall. Perhaps, this could indicate farmers’ response to rainfall variability by diversifying agricultural production options (i.e. agroforestry system), by replacing the more risk-prone mono-cropping culture. The observed persistence and further expansion of traditional agroforestry (a combination of perennial crops and scattered trees) have implications in terms of enhancing biodiversity conservation and environmental protection. Overall, the land cover transitions that occurred over the last three decades suggest future conservation priorities for improved landscape management, with more emphasis on the most exposed natural vegetation ecosystems.

使用遥感对土地覆盖动态进行多时态分析可以确定土地覆盖变化的空间范围和平均速率。通过应用适当的变化分析方法，还可以区分土地覆盖变化是由于随机或系统过程的影响而发生的。与此相关，表征降雨变化和历史气象干旱事件可以了解它们对农业生态系统和植被覆盖动态的影响。因此，本研究评估了多时土地覆盖变化以应对人口压力和降雨变化对农业生态系统动态的可能影响。这是在埃塞俄比亚南部一个以农林业为主的传统景观上进行的。使用 1985 年获取的 Landsat 图像，2000 年和 2018 年，采用分类后土地覆盖变化分析方法来区分类别间转换的系统和随机过程。干旱事件和降雨变化动态的评估分别使用标准化降水指数 (SPI) 和降雨变异系数 (CV) 进行。Mann-Kendall 检验也用于检测单调降雨趋势。1981-2017 年间经过偏差校正的气候危害组红外降水站 (CHIRPS) 用于计算 SPI、CV 和 Mann-Kendall 趋势检验。分析表明，1985 年至 2018 年间，超过 41% 的景观经历了土地覆盖转变。 这主要是由于农业、城市地区和桉树种植园的系统和快速扩张，以牺牲自然植被生态系统为代价。因此，在过去 33 年（1985-2018 年）中，天然林、草地和湿地分别减少了 74.8%、83.3% 和 78.4%。本研究中确定的另一个主要土地覆盖变化是农林业取代了露天作物，主要是在集水区的西部。农林业的这种扩张似乎与较低的长期平均降雨量和变化更大的降雨量在空间上相关。或许，这可以表明农民通过多样化农业生产选择（即农林复合系统）、取代风险更大的单一种植文化来应对降雨变化。观察到的传统农林业（多年生作物和零星树木的组合）的持续存在和进一步扩张对加强生物多样性保护和环境保护具有影响。总体而言，过去 30 年发生的土地覆盖转变表明了未来改善景观管理的保护重点，更多地强调暴露程度最高的自然植被生态系统。