Urban Expansion and Green Space Dynamics in Niamey, Niger (1990–2023)

Abstract

The study examines the factors driving the development of green spaces in Niamey and its environs between 1990 and 2023. The paper investigates land use and land cover changes over the study period by analyzing important land uses, including agricultural land, bare soil, residential areas, vegetation cover, and water bodies, which were selected to represent the diversity of landscape features. The Maximum Likelihood Classifier was applied using 30 validation points per class to improve ground truthing accuracy. Pixel-based classification was performed using spectral similarity algorithms, calculating the probability of pixel affiliation with each LULC category. A high level of reliability in distinguishing land cover classes was determined with a Kappa coefficient ranging from 90.19% in 1990 to 95.36% in 2023. The study equally concluded that Climatic pressures, particularly water deficits during dry years, exacerbate vegetation degradation and inadequate vegetation maintenance in less strategic zones, urban expansion and unsustainable practices on ecological stability further contribute to green space loss and are termed as key factors influencing green space transformation in Niamey, indicating the increasing vulnerability to climate challenges that posed rising temperatures and flood risks in the study area. Therefore, the study offers actionable insights for formulating adaptive strategies that support urban resilience and promote sustainable land management in Sahelian cities.