page_title: Sergey Zimov
section_title: Pleistocene Park
hierarchical_section_title: Sergey Zimov / Professional highlights and accomplishments / Pleistocene Park
caption_attribution_description: English: Restored grasslands in Pleistocene Park, Siberia
context_page_description: Sergey Aphanasievich Zimov is a Russian scientist. He is a geophysicist who specialises in arctic and subarctic ecology. He is the Director of Northeast Scientific Station, a senior research fellow of the Pacific Institute for Geography, and one of the founders of Pleistocene Park. He is best known for his work in advocating the theory that human overhunting of large herbivores during the Pleistocene caused Siberia's grassland-steppe ecosystem to disappear and for raising awareness as to the important roles permafrost and thermokarst lakes play in the global carbon cycle.
  According to a colleague, Sergey Zimov is the most cited Russian earth scientist.
context_section_description: Zimov began the Pleistocene Park project in 1988 in northeastern Siberia near the Northeast Science Station in Cherskii, Sakha Republic, Russia. Pleistocene Park seeks to test the hypotheses that large herbivores maintained the Pleistocene tundra steppe and that overhunting by humans caused both the animals and Pleistocene ecosystem to vanish.
  The grassland-steppe ecosystem, which dominated Siberia during the Pleistocene, disappeared 10,000 years ago and was replaced by mossy and forested tundra. Concurrently, many of the large herbivores that roamed Siberia during the Pleistocene, including mammoths, woolly rhinoceroses, bison, horses, musk oxen, elk, saiga, and yaks, vanished from the region. Today, reindeer and moose are the only surviving large herbivores to roam Siberia. Zimov and colleagues believe that humans, with their constantly improving technology, overhunted the large herbivores and led to their extinction and extirpation.  Without herbivores grazing and trampling over the land, mosses, shrubs, and trees were able to take over and replace the grassland ecosystem.
  At Pleistocene Park, Zimov is attempting to re-create the Pleistocene grasslands to demonstrate that the grasslands would have persisted into the Holocene if humans did not overhunt the herds of Pleistocene herbivores that roamed and maintained the ecosystem. He has demonstrated that grasses take over the landscape 1–2 years after mosses are anthropogenically removed.  According to Zimov, reintroducing large herbivores to Siberia would initiate a positive feedback loop promoting the reestablishment of grassland ecosystems: "The animals, their hooves, they disturb the moss and let grasses grow instead. The soil dries out, the animals deposit their fertilizer, the grass grows more, and more animals can graze."
  Current efforts in the park include reintroducing surviving Pleistocene megafauna into the fenced enclosure until they reach densities to change the vegetation and soil to a steppe grassland ecosystem. Pleistocene Park currently covers an area of 160 km² (62 sq mi) and contains less than 100 large mammals representing six major herbivore species (horses, moose, reindeer, muskox, elk, and bison). Zimov's goal for Pleistocene Park is to increase the number of large herbivores to 20 per square kilometer before then reintroducing predators, including wolves, bears, and Siberian tigers.
  In 2007 a 35-meter high flux tower was erected in the park which constantly monitors the levels of methane, carbon dioxide, water vapor and energy (temperature) in the park's atmosphere.  The data among others contributes to the Global Monitoring Division of NOAA's Earth System Research Lab.
  Zimov’s concept of Pleistocene Park and repopulating the mammoth steppe is listed as one of the “100 most substantive solutions to global warming” by Project Drawdown.  The list, encompassing only technologically viable, existing solutions, was compiled by a team of over 200 scholars, scientists, policymakers, business leaders and activists; for each solution the carbon impact through the year 2050, the total and net cost to society, and the total lifetime savings were measured and modelled.
caption: Restored grasslands in Pleistocene Park
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