That's not necessarily true, robomatic. This article discusses research done on the caribou herd as well as other herds that shows a potential for serious impact on the caribou herd from petroleum development in the north slope...

http://www.absc.usgs.gov/1002/section3part5.htm

According to the following site, the consequences go far beyond just economic considerations for humans...

"The porcupine caribou herd are a vital part of ANWR's eco-system and therefore must be taken into great consideration when planning the most environmentally efficient way to extract oil . The porcupine' caribou herd's relation to the Coastal Plain is part of an unaltered system which brings new life to the Caribou after a long and harsh winter."

http://web.mit.edu/12.000/www/m2007/teams/finalwebsite/environment/te_pcaribou.html

And they have a good point. The caribou is a lynchpin species in that part of the world. They are not a species that can be eliminated without serious consequences for the whole system.