Spatiotemporal dynamics of Ramsar wetlands and freshwater resources: Technological innovations for ecosystem conservation.

Abstract

Aquatic ecosystems, particularly wetlands, are vulnerable to natural and anthropogenic influences. This study examines the Saman Bird Sanctuary and Keetham Lake, both Ramsar sites, using advanced remote sensing for water occurrence, land use and land cover (LULC), and water quality assessments. Sentinel data, processed in cloud computing, enabled land-use classification, water boundary delineation, and seasonal water occurrence mapping. A combination of Modified Normalized Difference Water Index (MNDWI), OTSU threshold segmentation, and Canny edge detection provided precise seasonal water boundaries. Study utilized a combination of the MNDWI, OTSU threshold segmentation, and Canny edge detection methods. These approaches allowed for precise delineation of seasonal water boundaries. Sixteen water quality parameters including pH, turbidity, dissolved oxygen (DO), chemical oxygen demand (COD), total hardness (TH), total alkalinity (TA), total dissolved solid (TDS), electrical conductivity (EC), phosphates (PO₄), nitrate (NO₃), chloride (Cl^-), fluoride (F^-), carbon dioxide (CO₂), silica (Si), iodine (I^-), and chromium (Cr^-) were analyzed and compared for both sites. Results showed significant LULC changes, particularly at Saman, with scrub forest, built-up areas, and agriculture increasing, while flooded vegetation and open water declined. Significant LULC changes were observed near Marsh wetland, where positive changes up to 42.17% were seen for built-up in surrounding regions, with an increase to 5.43 ha in 2021 from 3.14 ha in 2017. Positive change was observed for scrub forests up to 21.02%, with a rise of 2.18 ha. Vegetation in the marsh region, including seasonal grasses and hydrophytes, has shown an increase in extent up to 0.39 ha with a rise of 7.12%. Spatiotemporal water occurrence was analyzed across pre-monsoon, monsoon, and post-monsoon seasons using Sentinel-1 data. The study highlights the role of remote sensing and field-based water quality monitoring in understanding ecological shifts and anthropogenic pressures on wetlands. By integrating land-use changes and water quality analysis, this research provides critical information for planning and conservation efforts. It provides vital insights for conservation planning, advocating for continued monitoring and adaptive management to sustain these critical ecosystems. PRACTITIONER POINTS: Spatiotemporal surface water occurrence at two geographically different wetlands-lake and marsh wetland; LULC and its change analysis to evaluate the impact on wetlands and its surrounding environment-positive and negative changes; Boundary delineation to examine changes and identify low-lying areas during the pre- and post-monsoon; Comparative analysis of the water quality of two different wetlands; Insectivorous plant-Utricularia stellaris, was recorded from Northern India at the Saman Bird Sanctuary for the first time.