"The coastal plain is the biological heart of the Refuge, to which the vast Porcupine River caribou herd migrates each spring to give birth. The Department of Interior has concluded that development in the coastal plain would result in major adverse impacts on the caribou population. According to biologists from the Alaska Department of Fish and Game caribou inhabiting the oil fields do not thrive as well as members of the same herd that seldom encounter oil-related facilities."
"Interior Secretary Bruce Babbitt has likened drilling in the Refuge to damming up the Grand Canyon; "
The US's Department of the Interior's report can be found here.
http://www.absc.usgs.gov/1002/"From the mid-1970s through the mid-1980s, use of calving and summer habitats by Central Arctic herd caribou (Rangifer tarandus granti) declined near petroleum development infrastructure on Alaska’s arctic coastal plain (Cameron et al. 1979; Cameron and Whitten 1980; Smith and Cameron 1983; Whitten and Cameron 1983a, 1985; Dau and Cameron 1986)."
"Since 1978, changes in the distribution of calving caribou associated with the Kuparuk petroleum development area, west of Prudhoe Bay (Fig. 4.1), have been quantified using strip-transect surveys flown by helicopter.
"After construction of a road system near Milne Point, mean caribou abundance declined by more than two-thirds within 2 km from a road and was less than expected, overall, within 4 km; but nearly doubled 4-6 km from roads (Fig. 4.3) (Cameron et al. 1992b). Prior to road placement, caribou were found in a single, more-or-less continuous concentration roughly centered where the Milne Point Road was subsequently built. After construction of the road, a bimodal distribution with separate concentrations east and west of the road was clearly apparent (Fig. 4.4) (Smith and Cameron 1992), indicating avoidance of infrastructure by calving caribou."
Anyway there's alot more like that. There may have been a net increase in the caribo population but that was do to other factors. Oil fields DO lead to a decrease in caribou populations.
