Sound science helps protect Western Arctic habitat

Animals from the Teshekpuk Caribou Herd walk across tundra near the shore of Teshekpuk Lake.

Tim Woody

As a wildlife biologist, I have learned a lot from the western Arctic’s National Petroleum Reserve-Alaska, not the least of which was the error of my once-youthful ways.

When my career began in the late 1990s, one of my arguments for protecting the Arctic National Wildlife Refuge from oil drilling was that we already had a place for Arctic resource development — a place that actually had “petroleum reserve” as part of its name.

It was only later that I learned that the NPR-A, or Western Arctic Reserve, contains some of the best wildlife habitat in the Arctic. Many of these critical habitat areas need to be protected. Congress recognized this nearly 40 years ago when it told the Bureau of Land Management to set aside “Special Areas” within the reserve.

So over the past two years I have worked with colleagues from various government, industry and non-profit organizations to identify these important wildlife areas in the reserve, with a specific focus on the Teshekpuk Caribou Herd.

We’ve all likely seen photos of caribou grazing near oil-industry infrastructure on Alaska’s North Slope, so it’s easy to assume that caribou are not bothered by oil development. This couldn’t be further from the truth, though, when females have newborn calves. During this critical period of the year, disturbances associated with industrial development can push caribou away from their best food sources and the areas they use to keep their young safe from predators. This can result in lower survival rates for calves, and make adult females less likely to bear young the following year.

During certain periods of summer, mosquitoes can be so numerous that caribou will run for miles to escape them. If development blocked migratory routes to areas of insect relief, caribou could expend excessive amounts of energy, leaving them without sufficient fat stores to survive the following winter or to give birth the next spring. This is why it is important for us to know — before more oil development occurs in the Western Arctic Reserve — where the most important caribou habitat exists so that sensitive areas can be protected.

We collected data from more than 40 female caribou over a six-year period to determine which areas they use for calving and insect relief. Every couple of hours, the animals’ GPS-equipped collars would transmit their locations. 

Not only were we able to see where the caribou went throughout the year, but also which features of the landscape they were choosing to use. We wanted to know, for example, if females with new calves chose areas with a lot of shrubs, or if they preferred areas with low-lying vegetation. Once we knew which landscape features female caribou were choosing, we were able to map all of the areas on the landscape that had those features.

This analysis provided important information for caribou conservation in the reserve. We found that the most important areas for females to bear and raise their newborns were almost entirely restricted to the area surrounding Teshekpuk Lake. This was the only region in the herd’s summer range that we identified as offering a large expanse of ideal conditions for calving. These areas provided females with access to high-quality plant species that provide maximum nutrition for lactating females.

We also identified the areas that caribou select when mosquito harassment is low, and when it is high. When they were not being badly bothered by mosquitoes, caribou again selected the area around Teshekpuk Lake to forage, but once mosquitos became severe, the caribou moved to the coastline of the Arctic Ocean to take advantage of cooler temperatures and higher winds that reduce mosquito activity.

To reach these important areas on the coast, caribou had to pass through two narrow corridors on either side of Teshekpuk Lake. The need for these migratory routes makes it extremely important that they remain free of development that would hinder movement of the caribou herd.  

I’m pleased that the Western Arctic Reserve opened my eyes and taught me that this magnificent place is much more than just a source of oil. I’m also glad that my job gives me the opportunity to build a scientific case for protecting these special habitat areas for the herd.

Development will undoubtedly occur in the reserve, but with sound science we can help strike the right balance between development and conservation.