https://reviverestore.org/proj...
The tundra and much of the taiga – the sometimes swampy coniferous forest of high northern latitudes – were once a grassland ecosystem known as the “mammoth steppe.” It was home to abundant grazing herds of antelope, deer, caribou, horses, bison, and woolly mammoths. At the end of the Pleistocene, these herds vanished leading to an ecosystem conversion away from abundant grasses toward a more shrub-dominated community.
The tundra ecosystem that arose in the absence of these large grazing species is now affected by and contributing to human-driven climate change. Without large animals to compact and scrape away thick insulating layers of winter snow, extreme winter cold does not penetrate the soil. That fact, coupled with significantly warmer summers, accelerates the melting of the permafrost and the release of greenhouse gases that have been trapped for millennia. From a global carbon perspective, the carbon release from the melting of the world’s permafrost is equivalent to burning all the world’s forests 2 ½ times.
The work of Dr. Sergey Zimov shows promise that tundra can be converted back to grasslands with the introduction of grazers even 10,000 years after their disappearance.