Abstract

Green spaces are essential for urban quality of life, sustainable development, and climate change mitigation. Since 2010, Central Chile has experienced anunprecedented megadrought, with extreme years (2019 and 2021) considered as hyperdrought. Prolonged water stress can compromise vegetation's ability to provide key ecosystem services in urban environments, making it critical to understand urban greening evolution under such climatic pressure. In this study, we assessed the spatiotemporal impacts of the megadrought and hyperdrought on the Gran Valparaiso urban and periurban vegetation. Vegetation trends and extreme greenness anomalies were analyzed using Landsat harmonized time series of the Normalized Difference Vegetation Index (NDVI) and the non-parametric npphen method alongside precipitation to better understand climate-vegetation relationships. Results show negative effects of the megadrought in urban and periurban vegetation regardless the level of management, showing similar temporal patterns even for public urban green spaces where artificial watering is likely being applied. However, spatial patterns showed unequal levels of affectation. Inland and periurban communes were particularly vulnerable, showing a stronger correlation to precipitation while coastal communes like Vina del Mar showed vegetation patterns less dependent on winter rainfall, suggesting the influence of differential urban planning. Additionally, the analysis identified specific city sectors that diverged from the general trend of desiccation likely linked to localized urban processes. Our results suggest that urban management was not able to stop the negative consequences of the megadrought and, that in a global change scenario, the future urban greening planning should consider that the Gran Valparaiso will face droughts more frequently.