Remote Sensing-Based Spatiotemporal Assessment of Ecological Quality using RSEI from 2016 to 2025: Gala Lake Basin, Türkiye

Özgenç E.

JOURNAL OF ANATOLIAN ENVIRONMENTAL AND ANIMAL SCIENCES, cilt.11, ss.1-11, 2026 (TRDizin)

Özet

Wetland-agricultural basins are among the most sensitive landscapes to ecological change because vegetation dynamics, surface moisture, bare soil exposure, and thermal stress interact within the same hydrological system. However, long-term, basin-scale assessments integrating multiple dimensions of ecological quality remain limited for the Gala Lake Basin. This study assessed the spatiotemporal ecological quality of the Gala Lake Basin in Türkiye from 2016 to 2025 using the Remote Sensing Ecological Index (RSEI). The basin was selected because it contains Gala Lake, associated wetlands, agricultural lands, and seasonally variable water surfaces, making it a representative and environmentally important wetland- agricultural landscape in northwestern Türkiye. Landsat 8 OLI/TIRS and Landsat 9 OLI-2/TIRS-2 images were processed in Google Earth Engine (GEE) to derive NDVI, WET, NDBSI, and LST, representing greenness, wetness, dryness, and heat, respectively. MNDWI was used to mask open-water areas before RSEI construction. The four indicators were normalized and integrated using PCA, and annual RSEI maps were classified into five ecological quality levels. The results revealed that ecological quality in the basin showed strong interannual variability rather than a uniform trend. The mean RSEI reached its lowest value in 2022 (0.4911) and its highest value in 2025 (0.5469). Class-based analysis showed a clear reduction in low- ecological-quality areas and an expansion of moderate-ecological-quality areas by the end of the study period. PCA results confirmed that PC1 captured the dominant ecological gradient in all years, supporting its use for annual RSEI construction. This study provides a reproducible RSEI framework for monitoring ecological quality in wetland-agricultural basins and offers valuable spatial information to support long-term wetland management, conservation planning, and ecological restoration in the Gala Lake Basin.