Environment

Alaska Oil Fields and Caribou

by Matthew Cronin, PhD.

There is interest in increasing domestic U.S. oil production by beginning exploration in the Arctic National Wildlife Refuge (ANWR). Many people are concerned that oil exploration and development will hurt the wildlife in the refuge, particularly caribou. This is in large measure because they have been told that existing oil fields in the Prudhoe Bay region of Alaska have hurt caribou.

There has been a great amount of research on this issue, and the results actually show that caribou have fared quite well since oil field development began in the late 1970's. This is surprising to many people, because government agencies, environmental groups, and the media have reported that there are problems with the caribou and oil fields. If one looks at all the available information, this is a one-sided, and largely incorrect view. This should not be surprising, as the government agencies and environmental groups only receive funding if there is a perceived problem with caribou. They therefore tend to stress the potential negative effects and ignore positive indicators.

A series of scientific papers published since 1992 have shown that the caribou have increased dramatically during the period of oil field development and regularly use ranges in the oil fields (see attached list of papers). The positive results regarding oil fields and caribou are telling.

1. In 1998, a paper was published in the journal Arctic in which caribou were shown to use ranges in and around the oil fields at Prudhoe Bay. This paper was reported in The Yukon News, but not in Alaskan or other U.S. media.2. Another paper was published in 1998, in the journal Biological Conservation, showing that the caribou herd that uses the oil fields has increased dramatically (from about 5,000 to more than 23,000) since the oil fields were first developed.3. In 1995 several things happened.a. First, Congress considered opening ANWR to oil exploration, but the initiative failed.

b. Second, the caribou herd that uses the existing oil fields was censused in 1995. The numbers declined from 23,000 in 1992 to about 18,000 in 1995. Most notably, the numbers of caribou in the western part of the range (with the oil fields) declined from 14,842 in 1992 to 6,327 in 1995, while numbers in the eastern part of the range (without oil fields) increased from 8,602 to 11,766 during this period.

c. This was heralded in a front-page headline in the Anchorage Daily News as "Oil field caribou decline." The story focused on speculation that the decline was due to negative effects of the oil fields.

d. Senator Murkowski followed this article with statements (also reported in the Anchorage Daily News, but not on the front page) that the decline in caribou numbers was due to natural factors and not the oil fields.e. At this time, some biologists began to consider potential factors, other than oil field impacts, that could affect the herd numbers. They published a paper in The Journal of Wildlife Research in 1997 showing that population density, or simply movements of caribou between the ranges with and without oil fields, could explain the changes in caribou numbers between 1992-1995 better than oil field impacts.

f. The herd was censused in 1997 and increased from the 1995 levels, to over 19,000 caribou. More importantly, the number of caribou in the western range (with the oil fields) increased to 10,669 between 1995 and 1997, and the numbers in the eastern range (without oil fields) decreased to 9,061 caribou (see Table 1 and Fig. 1). Hence, the trends in caribou numbers in the eastern and western ranges between 1995 and 1997 were the reverse of the trends between 1992 and 1995. In addition, a census in the year 2000 showed the herd increased to 27,128. In 2000 there were increases in both the western (oil field) and eastern (no oil field) ranges (14,295 in the western range and 12,833 in the eastern range). This provides strong evidence that the oil fields did not cause the decline in caribou numbers between 1992 - 1995.

g. Incredibly, these dramatic reversals of the negative results of 1995 were not reported to the public!

h. It seems clear that the numbers of caribou in the eastern and western summer ranges of the herd fluctuate for reasons other than impacts from the oil fields. The western range with oil fields had high numbers in 1992, 1997, and 2000, and low numbers in 1995, relative to the eastern range (Table 1, Figure 1). As suggested previously in the 1997 Journal of Wildlife Research paper, movement of animals between the eastern and western ranges is a plausible explanation for the changes in numbers in the eastern and western summer ranges. Caribou are highly mobile and regularly make major changes in spatial distribution.

i. Other information also does not support the idea that the oil fields adversely affected caribou. From 1997 to 2000 the number of calves per 100 cows in the western (oil field) range was higher than or equal to those in the eastern (without oil fields) range.

j. The increase in the western range between 1995 and 1997 was reported in agency documents but not in the Environmental Impact Statement for the National Petroleum Reserve-Alaska (NPRA), or to our knowledge, in the media.k. Senator Murkowski's 1995 explanation for the decline in the herd was supported by the 1997 census, but no one noticed or reported it.

l. These positive results are being ignored by the media and the potential for exploration in ANWR and NPRA affected. The public deserves to know the entire story.

m. The above description of the caribou numbers and the lack of reporting of positive results by the media are paralleled in the scientific literature. Despite the publication of several papers in peer-reviewed scientific journals (see attached list), papers by University of Alaska researchers (Nelleman and Cameron 1996, 1998) don't cite them, nor entertain the possibility that the oil fields haven't affected the herd numbers. This is not universal as the ADF&G have acknowledged in their Wildlife Notebook Series (www.state.ak.us/local/akpages/FISH.GAME/notebook/biggame/caribou.htm) and memos (ADFG 1995) that the impacts of the oil fields and pipelines are not great.

n. The experience in the Prudhoe Bay oil fields is actually one of great success in wildlife management. Other species besides caribou, including grizzly bears, have increased since the oil fields were developed. Clearly, the ANWR could be explored and developed without seriously affecting the wildlife populations. It will just take dedicated planning and management.

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