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“Pleistocene rewilding offers an experimental framework to better understand the biology of a continent that vanished 13,000 yrs ago, while simulktaneously providing evolutionary, conservation, economic, and cultural incentives and benefits” (664). Pleistocene Re-Wilding. “Pleistocene Epoch
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“Pleistocene rewilding offers an experimental framework to better understand the biology of a continent that vanished 13,000 yrs ago, while simulktaneously providing evolutionary, conservation, economic, and cultural incentives and benefits” (664)
“Pleistocene Epoch 1.8 million-10,000 years ago This epoch is best known as the "Great Ice Age." Ice sheets and other glaciers encroach and retreat during four or five primary glacial periods. At its peak, as much as 30% of the Earth's surface is covered by glaciers, and parts of the northern oceans are frozen. The movement of the glaciers alters the landscape. Lakes, such as the Great Lakes in North America, are formed as ice sheets melt, and retreat. Global warming begins after the last glacial maximum, 18,000 years ago. The oldest species of Homo—Homo habilis—evolves. The flora and fauna in the regions not covered by ice are essentially the same as those of the earlier Pliocene Epoch. Mammalian evolution includes the development of large forms: woolly mammoth, woolly rhinoceros, musk ox, moose, reindeer, elephant, mastodon, bison, and ground sloth. In the Americas, large mammals, such as horses, camels, mammoths, mastodons, saber-toothed cats, and ground sloths, are entirely extinct by the end of this epoch.”
Rewilding!? Why? • Functional roles of megafauna is significant • Loss of megafauna may be both cause and result of degraded systems • Loss can lead to ecological chain reactions that lead to further extinctions
Species interactions are hard to understand even among extant species, never mind extinct ones. • But evidence of strong interactors left evidence of their influence through various evolutionary effects • E.g. “overbuilt” speed in North American pronghorn. Why is the pronghorn so fast? (next slide) • There are tons of anachronistic traits and dysfunctional interactions resulting from the loss of large vertebrates
Ecological benefits • Better understanding in ecology…natural laboratory • Disease reduction, e.g., lyme disease, other diseases carried by rodents • Species diversity • Climate change
Gray Wolves Loss of wolves resulted in in population increases of ungulate prey… • thereby intensifying herbivory • reducing distribution and abundance of various tree species, especially aspen • affects distribution of passerine birds • flood plain sediment • nutrient dynamics
Reintroduction of wolves to Yellowstone… “may even include a buffering of Yellowstone’s biodiversity to climate change”
Is it Possible? Przewalski Horses • Extinct in wild • Breeding program built new pop. • Two generations hardened in semi-reserves in Europe • Released back into NP in Mongolia
“Pleistocene rewilding could be part of a movement to transform conservation biology, which is currently too easily characterized as a “doom and gloom” discipline…because we have acquiesced to a default goal of exposing and merely slowing the rate of biodiversity loss. Together these attributes minimize excitement for conservation and even actively discourage it…Moving away from managing extinction and toward actively restoring ecological and evolutionary processes using Pleistocene history as a guide provides an exciting new platform for conservation biology.” (665)
Cultural and Economic Benefits • Humans have strong emotional and cultural relationships with megafauna • Between 1999-2004, more than 1.5 million people visited SD’s Wild Animal Park; by contrast, only 12 NPs received more than 1.5 million visitors in 2000. • The reintroduction of wolves to Yellowstone has resulted in an estimated $6-9 million extra per yr (versus an est. cost of $0.5-0.9 million per yr)
North American Peregrine Falcon • Falcons from 4 continents serve as proxy • California condor • Bolston tortoise • Camelids • US Camel Corps • Red Ghost • Cheetahs • Proboscideans • Holartic lions
Conservation benefits • “The late Pleistocene arrival of the very first Americans…and the cotemporaneous extinctions constitute a less arbitrary benchmark that is justifiable from multiple perspectives. Even more evidence points to early humans having precipitated the late Pleistocene extinction events…Such attestation also raises important ethical questions regarding our conservation benchmarks and strategies” (664)
Jurassic Park? “The scientists with the Mammoth Creation Project are hoping to find a mammoth that is sufficiently well preserved in the ice to enable them to extract sperm DNA from the frozen remains.They will then inject the sperm DNA into a female elephant, the mammoth's modern-day counterpart. By repeating the procedure with offspring, scientists say, they could produce a creature that is 88 percent mammoth within 50 years.”
Quagga The last quagga, died in August 1883, in a zoo in Amsterdam.
Challenges • Why Pleistocene as benchmark? • Habitats have not remained static • Invasive species? • Megafauna different than Pleistocene megafauna (e.g., 162 kg lion v 400 kg lion) • Economic/social disruption
1903 0 elephants 9 lions 8 buffalo a few cheetah 2003 7300 elephants 2300 lions 28,000 buffalo 250 cheetahs 700,000 tourists Kruger National Park
