Evaluating Environmental Quality Changes Using the Geospatial Ecological Index (GEI): A Case Study of Podi Watershed, Indonesia
Keywords:
GEI, Ecological Index, Environmental Quality, Ecological Resilience, Watershed, Remote SensingAbstract
Understanding long-term environmental dynamics is therefore essential for guiding restoration and conservation strategies. This study examines the spatiotemporal variation of environmental quality in the Podi Watershed, Central Sulawesi, over a thirty-year period (1994–2024) using the Geospatial Ecological Index (GEI). The GEI integrates four remote sensing-based indicators : vegetation greenness (PVI), moisture condition (MPDI), surface exposure (NDSI), and land surface temperature (LST) to provide a comprehensive representation of ecological conditions. Analysis conducted on the Google Earth Engine platform shows a moderate improvement in overall environmental quality, with the mean GEI increasing from 0.39 in 1994 to 0.44 in 2024. However, the minimum GEI declined from 0.23 to 0.05, reflecting severe degradation in upstream areas affected by a large-scale landslide. These results reveal clear spatial disparities in ecological quality, highlighting the need for targeted restoration in degraded zones and continued management in more stable areas. The findings provide useful insights into the application of spatial ecological indices for watershed-scale environmental assessments in tropical landscapes.
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