Many herbivores, such as butterfly larvae, are shifting their distribution poleward and to higher elevation in response to climate change. As a consequence, climate change may induce new interactions between species that never co-occurred or evolutionary shifts in the functional traits of species. However, shifts in trophic interactions across trophic levels have been poorly investigated and may play a primary role in how community will be impacted by climate change. The present study aims at understanding how alpine plant community and plant resistance to herbivores respond to increased herbivore pressure and changes in biotic interactions under climate change. To address these questions, we simulated the effect of increased herbivore pressure at high elevation by artificially increasing the abundance of orthopteran individuals in a controlled field experiment. We also set up OTC (open top chambers) greenhouses to measure the effect of increasing temperature on the plant community.