Urbanization and seasonal effects on the lake ecosystem dynamics from 2002 to 2022 in Bengaluru, South India

Land use transformation in the rapidly growing megacity of Bengaluru in South India has greatly influenced its lake ecosystems. To gain insights into the dynamics of lake ecosystems along an urban-rural gradient, we analyzed lake-cover changes (along with a 300m buffer zone) of six lakes from 2002 to 2022. The lakes studied were Bellandur and Dodda Bommasandra (urban), Attur and Puttenhalli (peri-urban), and Chudahalli and Vrishabhavathi (rural). Supervised maximum likelihood Land Use/Land Cover (LULC) classifications were conducted on 166 freely available, RGB Google Earth (GE) images to distinguish between macrophytes, algae, water, and dried land inside the lakes, and built-up and non built-up area in the buffer zone. Antagonistic relationships between macrophytes and algae were observed at all locations. Rainfall was positively correlated with the wet surface area (that is macrophytes, algae, and water) in comparatively dry lakes. Similarly, air temperature was negatively correlated with the wet surface area except for the Vrishabhavathi Lake. However, the built-up area in the buffer zone did not show a consistent correlation with the wet surface area, most likely because of sewage connections of certain lakes with distant urban areas.