Mammoth steppe
During the Last Glacial Maximum, the mammoth steppe was the Earth’s most extensive biome. It spanned from Spain to Canada and from the arctic islands to China. It had a cold, dry climate, the vegetation was dominated by palatable high-productivity grasses, herbs and willow shrubs, and the animal biomass was dominated by the bison, horse, and the woolly mammoth. This ecosystem covered wide areas of the northern part of the globe, thrived for approximately 100,000 years without major changes, and then suddenly became extinct about 12,000 years ago.