The whole of the Hardangervidda is above the tree line. Its alpine climate enables the presence of many species of arctic animals and plants further south than anywhere else in Europe. Its wild reindeer herds are among the largest in the world, with some 15,000 animals recorded in 1996 and about 8,000 in 2008. They migrate across the plateau during the year, moving from their winter grazing lands on the east side of the Hardangervidda, where they graze on lichen, to their breeding grounds in the more fertile west of the plateau. On August 26, 2016, 323 were killed by lightning, prompting a Norwegian Environment Agency discussion on whether to leave so many corpses in the open.