New paper in Global Change Biology suggests no carbon limitation of aboveground growth in alpine plants

Patrick Möhl, Erika Hiltbrunner, and Christian Körner addressed the question whether biomass production in the most common type of alpine grassland in the Alps is carbon limited. Instead of varying the CO2 supply, they adopted another approach by gradually removing sunlight from 100% to 44%. Shading for three entire seasons did not affect stand level aboveground biomass, suggesting that carbon was not a limiting resource. Yet, reduced belowground biomass indicated a shift in the allocation pattern under shade. The linked video shows how the movement of the sun imposed a spatial shade gradient on the vegetation, from 100% light outside the range of shade to a minimum at the center of the grids.