Spatio-Temporal Dynamics of Urban Vegetation and Climate Impacts on Market Gardening Systems: Insights from NDVI and Participatory Data in Grand Nokoué, Benin

The degradation of vegetation cover and the vulnerability of urban market gardening systems to climate risks are a major challenge for food security in peri−urban areas. This study analyzes the spatio−temporal dynamics of vegetation using the NDVI index and assesses its correspondence with producers' perceptions of hydroclimatic impacts. NDVIs were extracted from the MODIS MOD13Q1 product via Google Earth Engine, with a spatial resolution of 250 m × 250 m and a temporal resolution of 16 days, then processed in Python using the xarray library. Additionally, 369 producers in Grand Nokoué were surveyed about the risks of flooding, drought, and heat waves, as well as the adaptation strategies they implement. The results reveal a decline in areas with a moderate to high NDVI index (between 0.41 and 0.81) and an expansion of areas with a low or very low NDVI index (below 0.41), reflecting increased fragmentation and degradation of vegetation cover. Producers' perceptions confirm this vulnerability and reveal different strategies depending on the type of crop and risk, including irrigation, temporary abandonment of plots, agroforestry, and the adoption of resilient crops. These observations highlight the need to implement targeted policies and appropriate agroecological practices in order to strengthen the resilience of urban market gardening systems to extreme climate risks.