Abstract
Alpine plant communities occur at the cold edge of vascular plant distributions, with many species having special adaptations to short growing seasons, low temperatures, and infertile soils. Climate warming has the potential to alter alpine plant phenology and physiology, species interactions, community structure, species distributions, and ecosystem processes through effects on temperature, snow, and moisture regimes. Here, we review the state of understanding of alpine species, community, and ecosystem responses to climate change, with an emphasis on what has been learned from controlled experiments. We conclude that many alpine plant communities are already responding to climate warming, with changes contingent on hydroclimate setting and local edaphic factors that modulate species use of greater nitrogen and phosphorous availability, migration to newly suitable sites, and success relative to neighboring species and migrants from lower elevations. Understanding the complex set of interactions required for predicting future change calls for more integrated experiments that explicitly address multiple interacting abiotic and biotic factors.