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Transcript of Pleistocene Re-Wilding
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 Epoch1.8 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 HomoHomo habilisevolves. 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.
Mammoths, mastodons, etc
Teratornis incredibilis 16 ft wingspan
Rewilding!? Why?Functional roles of megafauna is significantLoss of megafauna may be both cause and result of degraded systemsLoss 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 benefitsBetter understanding in ecologynatural laboratoryDisease reduction, e.g., lyme disease, other diseases carried by rodentsSpecies diversityClimate change
Gray WolvesLoss of wolves resulted in in population increases of ungulate preythereby intensifying herbivoryreducing distribution and abundance of various tree species, especially aspenaffects distribution of passerine birdsflood plain sedimentnutrient dynamics
Reintroduction of wolves to Yellowstonemay even include a buffering of Yellowstones biodiversity to climate change
Is it Possible? Przewalski HorsesExtinct in wildBreeding program built new pop.Two generations hardened in semi-reserves in EuropeReleased 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 disciplinebecause 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 itMoving 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 BenefitsHumans have strong emotional and cultural relationships with megafaunaBetween 1999-2004, more than 1.5 million people visited SDs 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 FalconFalcons from 4 continents serve as proxyCalifornia condorBolston tortoiseCamelidsUS Camel CorpsRed GhostCheetahsProboscideansHolartic lions
The late Pleistocene arrival of the very first Americansand 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 eventsSuch 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.
QuaggaThe last quagga, died in August 1883, in a zoo in Amsterdam.
Henry, born 2005
ChallengesWhy Pleistocene as benchmark?Habitats have not remained staticInvasive species?Megafauna different than Pleistocene megafauna (e.g., 162 kg lion v 400 kg lion)Economic/social disruption
Kruger National Park19030 elephants9 lions8 buffaloa few cheetah20037300 elephants2300 lions28,000 buffalo250 cheetahs700,000 tourists