Laura Niven sends a link to this Wired magazine piece on the controversial practice of "Re- Wilding" -- reintroducing the megafauna to environments that have lost them.
To me the most interesting part is that Sergey Zimov's Pleistocene Park is succeeding as predicted in changing swampy taiga to biologically more productive steppe.
This agrees with the premises of an intriguing book, William Stolzenburg's Where the Wild Things Were. This is one I expect many readers of the blog should check out. In it, Stolzenburg examines in detail such seemingly unrelated phenomena as the deer- dominated eastern forest (and its other problem, the rise of fragmentation and small predators with no checks on their numbers, leading to bird species losses previously blamed on Central American deforestation); how cougars protect some public lands in Utah from losing their cottonwoods, while ones with heavier human use lose them; and how the loss of predators on islands in South American reservoirs leads by steps to the domination of leaf-cutter ants, which devastate them.
I thought the most interesting part was a chapter telling how the study of sea otter and seal predation by killer whales led some biologists to realize that they had only turned to such "little" prey because their original food source was great whales, an utterly un- PC fact that still is controversial in some quarters. But they have seen a chilling scene of orcas ganging up on a pod of sperm whales, who form into a circle with heads in (to no avail-- apparently most were killed!) Stolzenburg reminds us that the old whalers called them "whale killers", and that their teeth are virtually identical to those of a Tyrannosaur. "The killer whale came equipped for more than mere one- ton sea lions."
Stolzenburg makes a case that the top predators ultimately "control" everything from songbirds to kelp forests. In most habitats we may not know what "natural" looks like.
Eagles and Otters ( and Killers)
The complex ecological web of the North Pacific has been undergoing some radical changes in the last decades, and scientists are only starting to untangle them. Dr. Jim Estes has followed one thread connecting animals as diverse as eagles and otters, which has re-emphasized the complexity and interconnections of these ecosystems. He's found that an as-yet unexplained shift in killer whale diets to hunting sea otters has caused the otter population to decline up to 99% in the Aleutian archipelago. This has caused sea-urchin populations to grow unchecked, and they've devastated the kelp beds. This has meant that eagles, who eat fish from the kelp beds (and baby sea-otters) are now hunting seabirds. Dr Estes is a Professor of Ecology and Evolutionary Biology at the University of California at Santa Cruz.
Listen to the file for the full interview.
This absolutely fascinating web is covered in the book-- sorry I didn't go into it in more detail. It is a good read besides.
And I should add, much about Estes' work.
"In most habitats we may not know what "natural" looks like."
If "natural" means "completely unaffected by mankind" then I don't think we'll ever know. And I doubt we can (or should) bring back an ecosystem that's been lost for 10,000 years. A whole lot of skyscrapers have sprung up since then. It would probably be more feasible to wait for the total collapse of civilization and consequent evolution of brand-new giant herbivores and predators.
Although...it really *would* be awesome to have wild elephants in America again.^__^
All this SOUNDS wonderful to us Nature lovers, but is so impractical(and EXPENSIVE!) as to likely never happen. At least in regards to some of the animals mentioned--like the elephants, for example. Subspecies are subspecies for a REASON--often an enviromental one, and trying to put tropically adapted elephants virtually anywhere in North America will not work--our present elephants are very cold sensitive, as any zoo that keeps them will tell you. Then there is that whole too-dang-many-humans problem. Nothing wrong with keeping them and caring for them in large, fenced acreages, in as natural a setting as possible, as John Varty has done with his tigers in Africa, in the hopes that maybe one day there will be a place for them--certainly a better life than most zoos. If nothing else, perhaps this will inadvertantly preserve them for that inevitable collapse of modern man, and will provide our ancestors something to hunt several millenia(or sooner...) from now!..L.B.
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