Donlan, Greene. et al. Re-wilding North America
1. OVERVIEW OF ARGUMENT
2. Re-wilding is justified on ecological, evolutionary, economic, aesthetic and ethical grounds
3. Use closely related existing species as proxies for extinct large vertebrates
a. Proxy is a substitute authorized to act for another
4. North America lost most of its large vertebrate species, its megafauna, 13,000 years ago
a. 13,000 years ago a better baseline than restore to 1492
5. Humans were probably at least partly responsible for their (Pleistocene megafauna) extinction
a. Our subsequent activities curtailed evolutionary potential of most remaining large vertebrates (explain)
6. We have an ethical responsibility to redress these problems
7. PRW is also important as it will help preserve endangered megafauna (e.g., keep elephants and lions from going extinct)
a. “Africa’s large mammals are dying, stranded on a continent where wars are waging over scarce resources”
b. Extinction of many of these species by end of 21st century appears likely
c. Way to preserve global megafauna heritage
d. System of reserves across several continents best hope for long term survival of large mammals
8. PRW will restore some of evolutionary and ecological potential lost 13,000 years ago
a. Extinction of large vertebrates in Americas had significant ecological and evolutionary effects
b. Large carnivores/herbivores often play important roles in maintaining biodiversity (tropic cascades)
c. Many extinct mammals must have shaped evolution of species we know today
d. E.g., American cheetah shaped pronghorn antelope speed
i. By bringing it back we add ecological and evolutionary potential
e. But if megafauna had significant ecological and evolutionary effects, their extinction would also have serious effects, suggesting that habitat today is not all that adapted to those species anymore.
9. Pleistocene parks: Ecological history parks covering vast areas of economically depressed parts of Great Plains
a. Create large ecological reserves in the American Great Plains
b. Number of people in great plains declining.
c. Offers future conservation opportunities
d. Create jobs and eco-tourism benefits
e. Perimeter fencing for otherwise free roaming ungulates, elephants, and large carnivores
10. PRW will increase, not decrease support for conservation efforts
a. People love to see large animals
b. Visits to public and private parks with these megafauna and resultant increased understanding of ecological and evolutionary history could increase support for conservation
11. Reject hands-off wilderness approach to conservation
a. Earth’s biosphere is no longer pristine anywhere
b. No matter what we do we will alter course of evolution
c. “As much as we wish otherwise, humans will continue to cause extinctions, change ecosystems and alter course of evolution”
d. Want to reinvigorate wild places as widely and rapidly as prudently possible
e. This is a response to the worry PRW involves too much interference with nature
12. EXAMPLES OF MEGAFAUNA PROPOSED FOR RESTORATION
a. Tortoises, Horses, Camels, Cheetahs, Elephants, Lions
13. Tortoise: Bring 100 pound Bolston tortoise back into New Mexico
a. Still exists in Mexico, used to be in American southwest until end of Pleistocene
b. “Restoring North America’s largest surviving temperate terrestrial reptile to its prehistoric range could bring ecological, evolutionary, economic and cultural benefits, with no apparent costs”
c. Note it still exists, so not a proxy (perhaps?)
d. Its current habitat is somewhat nearby
e. Is it an exotic?
a. Horses originated in N.A and many species were present in late Pleistocene (History of American Horses), but then disappeared and the returned to N.A. with European invasion in 1500s; wild horses today are descendants of these
b. Feral horses and asses widely viewed as pests in U.S., are plausible proxies for extinct American species.
c. Given that most European/African horse species critically endangered, establishing Asian asses and horses (Przewalski’s horse) in NA might help prevent extinction
d. Also restore horse species to their evolutionary homeland
a. Originated in N.A., went extinct here during Pleistocene
b. Endangered Bactrian (Mongolian Gobi Desert) camels are good proxies for extinct N.A. camel species
c. Might benefit NA ecosystems by browsing on woody plants that today dominate southwest landscapes
d. Also econ benefits–depends on local contexts
16. Begin maintaining African cheetah, Asian and African elephants and lions on private property
a. They are already in captivity in U.S.
b. Will need to provide with large protected areas of appropriate habitat and live prey
c. Large tracks of private land can be used
d. Now 77,000 large mammals, mostly ungulates, but some cheetahs, camels and kangaroos) roam free on Texas ranches.
17. African cheetah–a close relative of American cheetah–only a modest change of persisting in the wild in next century
a. Some of the 1000 captive cheetahs could be used for rewilding
b. Free-roaming, managed cheetahs in Southwest U.S.
c. Save fastest carnivore from extinction
d. Restore strong interaction with pronghorn
e. Ecotourism as economic alternative for ranchers
f. There are cheetahs, elephants and lions on private property already
18. Elephants: Three species in the elephant type family where in NA in Pleistocene
a. Asian/African elephants in grave danger
b. Elephants inhibit woodland regeneration and promote grasslands, as likely did the Mastodons and Mammoths in Pleistocene
i. They could suppress woody plants that threaten western grasslands
c. Use captive U.S. stocks of elephants and some of the 16,000 domesticated elephants in Asia to reintroduce in NA
d. Fencing to reduce human/elephant conflicts would be main economic cost
e. But good ecotourist alternative for ranchers
a. Lions play pivotal ecological role in Serengeti, are increasingly threatened and are critically endangered
b. Replacing extinct American lion would have aesthetic and economic benefits
21. One: Proxies not genetically identical
a. E.g., Existing lions and cheetahs somewhat smaller
22. Reply: Same is relative
23. No one is complaining about Peregrine falcon restoration from proxies
a. Peregrine falcon reintroduction in N.A.
b. Captive bred birds from 7 subspecies on four continents used
c. No difference in subsequent breeding success
d. Subspecies now serves as collective proxy for extinct Midwestern peregrine falcon
24. Two: Habitats have not remained static over millennia
25. Three: Likely to be unexpected ecological and social consequences of re-introduction
26. Reply: Address problems by sound research, careful management, public discussion, case by case experiments before large releases take place
28. In this century, by default or design, we will constrain the breadth and future evolutionary complexity of life on Earth
a. Create even more pest-weed dominated landscapes
b. Extinction of most or all large vertebrates
c. Continuing struggle to slow loss of biodiversity
29. Pleistocene rewilding an optimistic conservation strategy
a. Negative slant of current conservation philosophy
b. Settle for American wilderness emptier than just 100 centuries ago?
c. Risk extinction of world’s megafauna?
d. Conservation biology moves from managing extinction to actively restoring natural processes
Questions on Donlan, Greene. et al. Re-wilding North America
1. Describe the Pleistocene Re-wilding (PRW) proposal. What would it involve? Give some examples of the species proposed to be “rewilded” and how would it be done?
2. What are the arguments for PRW its proponents give? Consider and explain the ecological, evolutionary, economic, aesthetic and ethical considerations in its favor. What do you think of these arguments?
3. Explain and assess from your own point of view the moral argument for PRW.
4. Using a concrete examples, explain how its proponents think PRW restore and enhance evolutionary and ecological potential.
5. How to PRW advocates respond to the objection that PRW involves interference with nature? Is this a successful response?
6. Is PRW an optimistic as opposed to a pessimistic conservation strategy?