Habitat change driven by land-use dynamics threatens ecosystem resilience and biodiversity in the Himalayan hotspot regions. This study investigates spatiotemporal landscape transformations in Namchi, Sikkim, from 2004 to 2024, using multi-temporal satellite imagery and a Random Forest classifier implemented in Google Earth Engine. NDVI and GNDVI indices were applied to assess vegetation health and forest degradation, supported by field survey validation. Forest cover declined markedly from 289.80 km2 (38.64%) in 2004 to 244.15 km2 (32.55%) in 2024, primarily due to deforestation, agricultural expansion, and urban development. Concurrently, grass/scrubland expanded from 216.38 km2 to 242.85 km2, indicating secondary vegetation spread. Agricultural land increased by 30.72%, while settlement areas rose by 70.28%. A drop in mean NDVI from 0.66 to 0.54 signals increasing vegetation stress and ecological degradation. These land cover shifts have significantly impaired ecosystem hotspot functions, especially water regulation and biodiversity support. The observed patterns highlight the accelerating pressure of anthropogenic change on fragile Himalayan systems. This study emphasizes the urgent need for conservation action, including reforestation, ecological restoration, and sustainable land-use practices, to curb habitat degradation and enhance ecosystem resilience. The findings offer critical spatial evidence to inform regional planning and policy frameworks aimed at balancing development with long-term environmental sustainability in climate-sensitive mountain landscapes.