杏吧原创

The migration of America鈥檚 great mammals is being cut off by encroaching human habitation and energy plants and pipelines.

The problem has prompted a US wildlife biologist to recommend the establishment of 鈥渘ational migration corridors鈥� to protect the routes these animals have used for at least the last 5800 years.

Virtually every large, migrating North American animal outside of Alaska lives in the Yellowstone National Park ecosystem. However, many of their migration routes are now being truncated.

Joel Berger, senior scientist with the Wildlife Conservation Society, says that 100 per cent of bison routes, 78 per cent of pronghorn antelope routes and 58 per cent of elk migration routes have been lost. However, migration of moose and mule deer is undisturbed.

Round trip

Yellowstone pronghorn undertake a roundtrip migration of 430 kilometres on average. Most pass through an 800 metre-wide bottleneck in Wyoming known as Trapper鈥檚 Point 鈥� an area now being developed for oil and gas.

Bison no longer migrate from Yellowstone at all. Those that attempt to move into Montana beyond park boundaries are shot because ranchers fear the spread of brucellosis to cattle.

Data on historical bison migrations is anecdotal, but they are believed to have travelled as far as 600 kilometres during their seasonal journeys.

鈥淭he number of oil and gas wells going in is so phenomenal that it is altering an area that was a natural environment and turning it into an industrial landscape,鈥� says the Sierra Club鈥檚 Kirk Koepsel.

鈥淚f people care about spectacular processes that once crossed vast landscapes, we鈥檝e got to be creative and do things now,鈥� he told New 杏吧原创. 鈥淥therwise, no one is going to see long distance migration outside of the Arctic.鈥�