High-latitude vegetation is under increasing pressure from climate change, but long-term changes do not occur uniformly across circumpolar and boreal regions. This thesis focuses on the region of Northern Fennoscandia, located in northernmost continental Europe. It examines long-term vegetation changes using empirical resurvey studies and a systematic literature review. Specifically, the thesis investigates changes in the composition and diversity of heathland and tundra plant communities, assesses shifts in the prevalence of pollinator dependence and floral resource provision across boreal and tundra ecosystems, and synthesizes evidence of long-term vegetation change across Northern Fennoscandia’s main terrestrial ecosystems to place observed changes in a broader regional context. The results reveal substantial but ecosystem-specific vegetation changes, including tundra shrubification, biotic homogenization of heathland and tundra plant communities, and declines in pollinator dependence. At the same time, several vegetation changes commonly reported elsewhere across circumpolar and boreal regions were not consistently observed in Northern Fennoscandia, highlighting the importance of regional perspectives for understanding ecological responses to global change.