Seasonal floods are a recurring threat in the arid Sahelian zones of Cameroon, particularly in Koza in the mountainous area and in Kousseri, Makari and Yagoua in the plains. This article analyzes their impacts on terrestrial biodiversity and the resilience of local populations. Based on an approach combining field surveys, sociological surveys and environmental analyses, we highlight the adaptive strategies of communities and ecological indicators of species survival. The results show that there is a loss of 30 to 40% of plant species richness, with the Shannon index falling on average from 1.8 to 1.2 after the floods in the Yagoua and Makari plain, indicating a loss of plant and animal diversity affecting more species adapted to dry environments more vulnerable to prolonged flooding. The majority of households perceive floods as a major threat (> 78%) because the significant loss of crops (up to 580 kg/year lost on average per household), with significant livestock losses, accentuate economic precariousness. The reduction in meals and increase in debt (between 52% and 66% of households) reduce their food consumption after floods, and post-flood debts reach on average 95,000 FCFA per household.