Can oil and caribou mix?
July 2005
This year's Porcupine Caribou Herd calves have been born. The cycle of life for the caribou has been renewed. Soon they will be making their first seasonal migration south to the wintering grounds in the southern Brooks Range in Alaska and the Ogilvie and Richardson Mountains in the Yukon. These animals have a long trip ahead of them. Satellite collars have shown that the average female travels over 4,300 kilometers each year.
The first few weeks of a caribou calf's life are the most critical for survival. Twenty-five percent of the calves do not make it past the first month. Birth defects, malnutrition, and predators take the majority of the unfortunate calves. Because the predators are concentrated in the foothills and the mountains, calves have a real advantage for survival when they are born on the coastal plain of the arctic. But this pristine birthplace of the Porcupine Caribou Herd and vital habitat for numerous other species is in jeopardy because of our own human activities. The real possibility of oil and gas exploration occurring in the coastal calving grounds makes the fate of these calves and their future offspring uncertain.
Many biologists, naturalists, and First Nation people have said that oil development in the concentrated calving grounds of the Arctic Refuge would be detrimental to the viability of the herd's population. The caribou already have to overcome many obstacles in order to survive through their migration. Predation from a variety of animals including human hunters; hazardous river crossings; deep snow; injury; varying degrees of food quality, quantity, and availability; disease, and insect harassment – which decreases time spent feeding – all take their toll on the caribou herd. Along with all these factors will be the added influences of ongoing climate change.
A warmer climate could increase the amount of insects, alter precipitation and snowmelt regimes, and change the composition of northern plant communities. It is difficult to predict the effects of climate change and how these environmental changes will affect the Porcupine Caribou Herd. What is known is that when there has been an early spring, and therefore early plant green-up, the percent of female caribou giving birth in the area of the 1002 lands has increased.
The concentrated calving area occupies only about 12 percent of the herd's entire range and yet each spring the caribou make the arduous journey north to this critical coastal habitat so they can give birth. Between 1983 and 2001 an average of 43 percent of the Porcupine Caribou cows calved in the 1002 lands of the Arctic Refuge.
In the natural world when there are major changes to the environment animals either have to adapt, move or die. In the case of the Porcupine Caribou Herd that major change could be oil and gas extraction in the critical calving grounds of the 1002 lands of the Arctic National Wildlife Refuge. What will they do to stay alive?
Oil exploration and development has already occurred in the range of an arctic caribou herd, the Central Arctic herd of Alaska. Oil exploration in Prudhoe Bay, Alaska, began in the early 1970s. What started as a small development with relatively little impact has grown to a large industrial oil complex with roads, airstrips, drill pads, gravel quarries, the Trans-Alaska Pipeline, as well as the unavoidable oil spills associated with any oil activity.
It is true that since the development of Prudhoe Bay the Central Arctic herd has increased in size from about 5,000 animals in 1978 to 31,000 in the 2003 census. This is not to say that oil development and caribou can coexist because within this period of time most North American caribou herds have shown some population growth. It should be noted too that while other caribou herds were still growing in size the Porcupine Caribou herd started to decline at a rate of approximately 3.5 percent per year since 1989. There is no way of knowing how much the Central Arctic herd could have grown without development in the region.
The U.S. National Academy of Sciences has studied and documented some of the cumulative impacts on the environment that have occurred since development at the Prudhoe Bay oil complex, the largest oil field in North America. It has found that:
- During calving, the caribou cows and calves avoid human activity. This significant avoidance has been measured to show that they stay 4 km away from roads and other infrastructure.
- From 1980 to 1993 the Central Arctic herd has used the land around the oil complex 78 percent less. Movement through the developed area has decreased by 90 percent.
- The average birth rate, the number of calves born per 100 females, for caribou that were exposed to development was 74 percent (1988-2001). The average birth rate for caribou in undisturbed areas was 88 percent.
- Although the average difference in birth rate was 14 percent for the years of study the difference was most dramatic in the years after there was high insect harassment. In those years the added cumulative effects of insect harassment on caribou exposed to development had resulted in a 25 percent lower birth rate.
In the Central Arctic herd some of the caribou may have adapted to the disturbances of oil activity in the coastal regions of Prudhoe Bay while the majority have moved away. When development expanded to the west of Prudhoe Bay the concentrated calving area shifted away from the drilling activity and the cows moved further to the south. The pregnant females were able to move to another region but this undisturbed area is of lower quality habitat. Studies done on the habitat show that the nutritional value of the vegetation in this southern region is noticeably lower than the quality of plants closer to the coast.
One of the reasons the Central Arctic herd was able to move to another undisturbed area is because it has more access to the coastal plain than does the Porcupine Caribou herd. The coastal plain where the 33,000 Central Arctic caribou cows can calve is approximately 18,600 square kilometers, whereas the 123,000 Porcupine Caribou have only about 11,900 square kilometers. The Porcupine Caribou herd's calving grounds are of the utmost importance to the caribou as well as the 16 communities that rely on the caribou for sustenance hunting.
Even if you find it difficult to swallow all of the scientific evidence, one fact is certain: The potential oil supply in the 1002 lands is limited – it will run out. And if oil and gas development does go ahead, as the current U.S. government would like it to, we may just see this question answered: After all the oil is gone... will there still be caribou?
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