Analyzing the impacts of land use and land cover (LULC) changes on wetland Dynamics in Aba Samuel reservoir and its surroundings, central Ethiopia

Abstract

This study investigates the impacts of land use and land cover (LULC) changes on wetlands ecosystems in the Aba Samuel Reservoir area, Ethiopia, over 30 years from 1994 to 2024. Remote sensing (RS), geographic information systems (GIS), and cloud-based processing using Google Earth Engine (GEE) were employed to analyze multi-temporal Landsat imagery. The Random Forest (RF) algorithm implemented in GEE was used to classify LULC and detect temporal trends. To identify the drivers of LULC changes, field observation and local knowledge were integrated into the analysis. Results indicate that agricultural expansion, settlement growth, and population pressure are the primary drivers of landscape transformation. Cropland increased substantially from 827.6 to 2731.5 ha, and settlements expanded from 4.4 to 140.8 ha, while waterbodies and wetlands decreased sharply by 79.1% and nearly 100%, respectively, reflecting severe ecosystem degradation. NDVI analysis revealed a marked reduction in vegetation cover until 2014, followed by partial recovery in 2024, and NDWI confirmed the overall decline in surface water extent. These findings highlight biodiversity loss and disruption of critical ecosystem services, underscoring the urgent need for sustainable land and water management strategies to balance development with ecological preservation.