Bryophytes in the Arctic and Alpine regions are important in terms of biodiversity, cover and biomass. However, widespread shrubification of alpine and arctic tundra is underway and is predicted to increase in the future due to climate change, with potentially large impacts on bryophyte and lichen communities. Here we report on the relationship between deciduous shrubs and bryophytes and describe the responses of bryophyte cover, richness and diversity to 18 years of experimental warming in alpine Sweden. We found a significant negative relationship between deciduous shrub cover and bryophyte cover, but not bryophyte richness, in both a heath and a meadow ecosystem. Cover and richness of bryophytes both declined due to long-term warming, while diversity did not show any significant responses in the heath and meadow ecosystems. After 18 years, bryophyte cover had decreased by 71% and 26 in the heath and meadow, while richness declined by 39% and 26%, respectively. The decline in total bryophyte cover in both heath and meadow was driven by a general decline in many species, with only two individual species showing significant declines. In addition, species loss was slower than the general decline in bryophyte abundance.