History of the Mammoth Steppe
During the last Ice Age, high productive grazing ecosystems dominated most of the planet. High animal density, which can now be seen only in a few national parks in Africa (like Serengeti), were on every continent. The largest of all these ecosystems was the Mammoth steppe which spanned from Spain to Canada and from Arctic Islands to China. Millions of mammoths, bison, horses, reindeer, wolves and tigers maintained the grasslands. This ecosystem can exist in a wide variety of climates and was sustained through several glacial/interglacial cycles. However shortly after the end of the last Ice Age, 14500 years ago, humans started their expansion to Northern Eurasia passing through Bering strait and colonizing Americas. Unfortunately the technological development of humans has always outstripped our ability for sustainable land use. Facing millions of animals with no defending strategy against “new predators” people quickly collapsed animal populations. From Europe to Patagonia herbivores declined in numbers with numerous animal species going extinct.
It is hard to believe that primitive humans could kill all big herbivores in the high Siberian Arctic. However declining animal density for an extended period of time was enough for the ecosystem shift. In the Arctic, grasses and herbs cannot compete against slowly growing mosses, evergreen shrubs and larch trees without the help of animals. Herbivores harvest grasses, accelerate biological cycle and physically damage slowly growing plants. With the reduction of animal numbers hay and litter accumulated on the pastures, nutrient turnover slowed down and a few centuries later low-productive vegetation took over. Millions of square kilometers of high productive grasslands with fertile soils disappeared. In the new (modern) environment big herbivores like the Mammoth or Woolly Rhinoceros simply could not find enough forage to survive through the cold winters.
In the perception of most modern people the Arctic is an intact piece of wild nature. However real wild ecosystems there were destroyed by humans over ten thousand years ago. Current animal density in the Arctic is at least one hundred times lower than during the Pleistocene. Modern Arctic ecosystems can maintain limited number of animals and provide very little profit for people.
The idea of Pleistocene Park is to reverse the ecosystem shift which occurred 10 thousand years ago. If declining animal density for an extended period of time allowed grasslands to vanish, then artificially introducing herbivores to the Arctic and maintaining their existence will promote grass establishment and allow reviving of a sustainable high productive ecosystem, similar to Northern Serengeti.
The main difference between modern Arctic ecosystems and grazing ecosystems are the rates of the biological cycle. In the cold Arctic environment decomposition of organic matter is very slow and nutrients used for plant growth are stuck in dead litter for a long time before they can be available for new productivity. In the grazing ecosystems decomposition of organic matter happen in the stomachs of herbivores, and nutrient are quickly returned back to the system. This allows grazing ecosystems to produce much higher harvest and maintain much higher density of animals comparing with any modern Arctic ecosystem.
Restoration of pasture ecosystems in the Arctic can have a cooling effect on the climate
Permafrost carbon preservation
Permafrost is one of the largest carbon reservoirs. With the climate warming permafrost temperature increase and already now in different region in the Arctic recorded local permafrost degradation processes. At that microbes quickly convert formerly frozen organic matter into greenhouse gases. Currently temperature of permafrost is about 5 degree warmer than annual air temperature at the region. Such a difference form because in the winter soil and permafrost are protected from strong Arctic cooling by snow layer. In the grazing ecosystems, animals looking for forage in the winter trample down snow and destroy heat insulating layer. This allows deeper freezing of permafrost and thus protects it from degradation.
Unlike modern vegetation, grasses form a deep root system. This is essentially the process of absorbing CO2 from the atmosphere and storing it in the form of roots in the cold Arctic soils. Establishment of high productive grasslands on the big territory can be a long term sustainable mechanism for absorption of greenhouse gases from the atmosphere. In the Arctic soils has a much higher potential to store carbon comparing with above ground biomass (tree stems). Plus carbon in the soil is not subject to forest fires.
Grassland are lighter than shrublands or larch forest. Lighter surfaces reflect higher portion of sun back to space, keeping surface cooler. This effect is especially pronounced during April/May when sun in the Arctic is already active and dark tree stems absorb sun heat, while pastures are still covered with white snow and reflect most of the energy back to space.
Methane emissions reduction
Modern low productive Arctic vegetation has very slow evapotranspiration; therefore most of the modern arctic soil/surfaces are very moist. High productive grasses in turn dry out soils at that methane – very strong greenhouse gas, is not emitted.
In addition to mitigating climate change, creation of the “Northern Serengeti” will have a strong socio/economical effect on the lives of the local and indigenous people