Integration of Multi‐Sensor Remote Sensing for Environmental Monitoring: Assessment of Wetland Degradation in Semi‐Arid Ecosystems

ABSTRACT

Environmental monitoring of wetland ecosystems using conventional single‐sensor approaches faces significant limitations in assessment accuracy and temporal consistency. This study develops and validates an integrated environmental assessment framework combining optical and radar remote sensing for monitoring critical wetland degradation in semi‐arid ecosystems. The assessment methodology integrates Sentinel‐1 SAR data (VV and VH polarizations in both ascending and descending modes) with multiple Sentinel‐2 derived environmental indices, including water indices (AWEI, MNDWI, SWI, SMBWI, NDWI), vegetation indices (SAVI, NDVI, GDVI), and built‐up indices (SMI, NDBI). Environmental assessment of two critical wetlands in Pakistan's Soan Valley (2016–2019) reveals significant ecosystem degradation, with wetland extent diminishing from 24.1 km ² (4% of the 959.1 km ² study area) to 15.8 km ² (2%), representing a critical loss of 8.3 km ² of vital wetland habitat. The integrated assessment approach provided robust environmental monitoring capabilities, validated through strong correlations between MNDWI and SAR water masks (correlation coefficients: 0.47–0.68). Analysis of land use transitions reveals significant ecosystem transformation, with rangeland expansion from 349.1 km ² (36%) to 420.1 km ² (44%) replacing former wetland areas. The framework demonstrates enhanced capability in environmental change detection and ecosystem boundary delineation compared to single‐sensor optical or SAR approaches, achieving 15%–23% improvement in wetland boundary detection accuracy and maintaining consistent monitoring effectiveness under varying environmental conditions including cloud cover where optical‐only methods fail. This study provides both critical evidence of ecosystem degradation and establishes a robust environmental assessment methodology applicable to wetland management globally, particularly in semi‐arid regions facing similar environmental challenges.