Mohanty Smrutisikha, Pandey Prem Chandra
Department of Life Sciences, School of Natural Sciences, Shiv Nadar Institution of Eminence (Deemed to be University), Greater Noida, India.
Water Environ Res. 2025 May;97(5):e70072. doi: 10.1002/wer.70072.
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 (PO), nitrate (NO), chloride (Cl), fluoride (F), carbon dioxide (CO), 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.
水生生态系统,尤其是湿地,很容易受到自然和人为因素的影响。本研究利用先进的遥感技术对萨曼鸟类保护区和基特姆湖这两个拉姆萨尔湿地进行了水情、土地利用和土地覆盖(LULC)以及水质评估。通过云计算处理的哨兵数据实现了土地利用分类、水域边界划定和季节性水情测绘。改进的归一化差异水指数(MNDWI)、大津阈值分割和Canny边缘检测相结合,提供了精确的季节性水域边界。该研究采用了MNDWI、大津阈值分割和Canny边缘检测方法相结合的方式。这些方法能够精确划定季节性水域边界。分析并比较了两个地点的16个水质参数,包括pH值、浊度、溶解氧(DO)、化学需氧量(COD)、总硬度(TH)、总碱度(TA)、总溶解固体(TDS)、电导率(EC)、磷酸盐(PO)、硝酸盐(NO)、氯化物(Cl)、氟化物(F)、二氧化碳(CO)、二氧化硅(Si)、碘(I)和铬(Cr)。结果显示,土地利用和土地覆盖发生了显著变化,尤其是在萨曼,灌木林、建成区和农业用地增加,而被洪水淹没的植被和开阔水域减少。在沼泽湿地附近观察到显著的土地利用和土地覆盖变化,周边地区建成区的正向变化高达42.17%,从2017年的3.14公顷增加到2021年的5.43公顷。灌木林的正向变化高达21.02%,增加了2.18公顷。沼泽地区的植被,包括季节性草本植物和水生植物,面积增加了0.39公顷,增幅为7.12%。利用哨兵-1数据分析了季风前、季风期和季风后季节的时空水情。该研究强调了遥感和实地水质监测在理解湿地生态变化和人为压力方面的作用。通过整合土地利用变化和水质分析,本研究为规划和保护工作提供了关键信息。它为保护规划提供了重要见解,倡导持续监测和适应性管理,以维持这些关键生态系统。从业者要点:两个地理位置不同的湿地(湖泊和沼泽湿地)的时空地表水情;土地利用和土地覆盖及其变化分析,以评估对湿地及其周边环境的影响(正向和负向变化);边界划定,以检查季风前后的变化并识别低洼地区;两个不同湿地水质的比较分析;首次在印度北部的萨曼鸟类保护区记录到食虫植物——星芒狸藻。