Mountain ecology under climate change Climate warming causes shifts in the distributions of organisms and different organisms may move at different rates, resulting in changes in the composition and functioning of ecological communities. These effects are rarely considered in forecasts about the effects of climate change on biodiversity. Using experimental translocations, Descombes et al. investigated how differential upslope migration in alpine plants and their insect herbivores affects community interactions. Lowland herbivores modify the three-dimensional vegetation structure at higher altitudes, and this modified vegetation structure favors the coexistence of plant species, especially by favoring small-stature species. Reorganized trophic interactions will play an important role in driving plant community changes under future climate change. Science , this issue p. 1469