Both government and industry scientists acknowledge that the question of caribou in the oil fields of the Arctic is a very complex topic.
“It has been a challenge for us to try and study it and to make sense out of what that data has told us,” said Mike Joyce, a retired biologist who worked for ARCO Alaska Inc. and its successor, Phillips Alaska Inc.
Over 30 years of constant study, of trying to figure out how oil companies on the North Slope are interacting with the caribou, and how they respond to mitigation, the oil industry and government agencies have worked to find better ways to coexist with the caribou and other wildlife species.
In the Kuparuk River oil field, for example, when the oil companies first realized in the early 1970s that there was a caribou herd called the Central Arctic herd in the vicinity, scientists established the first population estimate of the herd at about 3,000 animals.
In three decades, regular censuses show the herd has grown to exceed 31,000 animals.
At the same time, industry plopped a 40-pad oil field down in the middle of the area where the Central Arctic caribou herd lives and calves, bringing to the area about 160 miles of roads, and hundreds of vehicles running back and forth in all directions at all times of the day.
The oil industry’s challenge has been to figure out how to understand what influence its presence is having on the caribou, their migration patterns and their very strong traditional use of the area. The herd, meanwhile, has continued to grow rapidly, and its traditional use patterns have had a high degree of annual variability, scientists say.
“When we start to think that maybe we are beginning to understand something that is going on, then the CAH loves to throw us a little curve and makes it a little puzzle, so that maybe the traditional use isn’t quite what we understood it to be. So it’s been a very difficult topic. It has created lots of debate,” Joyce told participants at a technology conference, “Established Oil & Gas Practices and Technologies on Alaska’s North Slope,” sponsored by the U.S. Department of Energy in April 2000.
Still, much has been learned about the herd over the past 30 years, and industry has adapted its operations to accommodate the caribou’s needs.
With the help of government and industry scientists, including independent consultants such as Alaska Biological Research in Fairbanks, significant gains have been made in understanding the species and its habitat.
The oil industry’s goal has been to have “happy caribou” — to allow the Central Arctic herd do what it wants to do, completely undisturbed, according to Joyce.
An image of “happy caribou” bedded down in the oil fields, with steel oilfield infrastructure in the background has been immortalized during the past decade in national debate over allowing oil and gas development in other areas of the North Slope currently off limits.
Spacing roads and pipelinesOne of the first issues that North Slope operators had to resolve was putting pipe and roads and traffic in the middle of the caribou herd’s movement patterns.
They tackled the gargantuan task of accumulating data on the herd’s movements to determine what the patterns are.
Imagine young grad students sitting in towers across the North Slope and tracking the actual movements of every individual caribou.
This rather low-tech undertaking resulted in a complex distribution map, a spaghetti diagram that showed movement patterns and how the caribou interacted with roads and pipelines when they encountered them.
“You’d like to see nice straight lines that run across it, but we don’t have straight lines — we have a whole mass of confusion,” Joyce said in 2000. “In the early days, the late ’70s to the early ’80s, pipelines were right on the ground, gravel roads were right next to the pipelines, and the caribou had no visual window to see if there was free range on the other side of that limit.”
As a result, the caribou did a lot of wandering and their distribution patterns reflected their confusion.
But industry researchers studied the problem and found that it wasn’t the gravel or the roads that caused problems.
Rather, it was the combination of low pipelines adjacent to the gravel roads, and as animals approached this obstacle, their line of sight was blocked.
The industry responded by building what amounted to sidewalks for the caribou over the pipelines — gravel ramps called “caribou ramps.”
“We built and studied several different designs in the late ’70s, early ’80s, and what we often found was that caribou would use the ramps sometimes, but they would not travel along the linear feature to search for a ramp. And often, they would cross right next to the ramps, without actually using the ramp,” Joyce recalled.
But the animals did use the ramps to some degree, so scientists concluded that the ramps could be beneficial in key areas, especially if researchers could figure out what preferred crossing locations might be.
They also learned that the caribou did not use the ramps in selective-search fashion.
Researchers also studied the pipelines. In the early days, the pipe was built right on the tundra surface. Welders hated to get down on their knees, and they hated to build scaffolding. Instead, they wanted to work at belt-high or chest-high levels, which often meant that the bottom of the pipe was too low for a caribou to walk under.
“We started looking at putting pipe up at a level of five feet high in the early 1980s, and found that the caribou had good passage success under that taller platform,” Joyce said.
So a new standard was born — a minimum of five feet from the ground to the bottom of the pipe. For linear features, pipelines in particular, from the early or mid-70s to the early to mid-80s, industry began to keep the pipe up off the tundra, and also to separate the pipe from the road. Instead of putting the pipeline right next to the road, the companies spaced them some distance apart.
Joyce said this practice evolved from a crude understanding and use of ice roads in the early days as a development technique. Instead of having a gravel pad for construction of the pipelines, the industry began to build pipelines from ice roads, thereby providing the distance needed to help the caribou get through.
No traffic jams for caribouThe next focus was traffic. Pipes were okay, using the right design and orientation. The gravel road itself was not a problem.
“It became clear to us that traffic was the prime stress in causing caribou to give up an attempt to cross a pipeline or a road. There were lots of trucks around, so traffic became the focus, and we studied traffic. We can’t control traffic. But if we provide caribou with plenty of space, they can get under the pipeline, check out the traffic, wait for the traffic if they need to, and then pass,” Joyce said.
The oil company soon realized that traffic management during caribou migration season would be necessary.
Other issues that greatly concerned the oil companies were how to allow the caribou unimpeded movement as they pursued their seasonal activities, and how to ensure that they maintained a healthy population and net production. Calving has to occur at a spot that is beneficial to the herd, with minimal predators, good forage and low snow cover. So the animals use traditional patterns for calving. However, those patterns have changed over time.
From the 1980s through the 1990s, a shift in caribou calving occurred in the Kuparuk area. The bulk of calving now occurs to the south and west of the oil field. Some calving still occurs in the Milne Point and Kuparuk fields, but over a 20-year period, most of the calving has shifted further south, according to researchers.
Why? And even more important, said Joyce, “What does it mean?”
Today, researchers still don’t know the answers to these questions.
Joyce said all kinds of variables influence caribou behavior from year to year — weather, snow and predators — all of which can cause stress within an area like Kuparuk.
But further study will help researchers get a feeling for whether the shift reflects a real problem, he said.
“Remember, our goal is healthy caribou populations — happy caribou,” he observed.
Joyce also said the number of calves being dropped every year per 100 cows, from the late 1970s through 1999, showed a lot of between-year variability. But when researchers compared what was happening in the Central Arctic herd with other herds and other species, they found a fair amount of commonality in terms of down years, he said.
Herd growth unimpededThe other component of “are the caribou happy and healthy?” depends on how the population is doing.
In 1972, when it was first recognized that the Central Arctic herd was a discrete group, there were only about 3,000 animals in the herd, Joyce said.
Over 30 years, the herd has grown ten-fold, with numbers currently exceeding 30,000 animals.
This growth pattern included a rather significant decline in the mid-90s that researchers still do not understand.
“We do know that there were a couple of hard winters at that point. We also know by looking at ungulates across the North Slope, that other caribou herds showed declines at about the same time. So this may have been weather-induced from those harsh winters. It is not clear,” Joyce said.
“Which brings me to maybe the most important lesson I’d like to share with you,” he told the technology conference in 2000. “For a disciplined wildlife scientist trying to figure out what the results are in terms of cause and effect, a couple of years of data doesn’t help you answer those questions. We’ve been studying this caribou herd for over 25 years, and we still have questions about what is happening with this herd.”
Joyce said it has taken a cooperative program working with government agencies, the North Slope Borough and village community residents, as well as some very powerful consultants with a lot of experience to try to gain the beginnings of an understanding.
Researchers agree that the discipline needs constant attention and surveillance and monitoring. The Central Arctic caribou herd is the perfect example of how important a continuous record of monitoring has been and will be for future oil development on the North Slope, Joyce said.
Fields provide insect reliefPopulation numbers, however, can help explain what the calving distribution shift means.
In 2000, Joyce said he believed the herd’s population was healthy, and that oil-field stress had caused no serious population-level disturbance at that point.
“We’ve talked about the fact that we also have learned behavior, habituation going on. For example, caribou need to go to the coastal plain for insect relief. They are harassed early by insects, and it’s very important to move to avoid this. A learned behavior that we have seen over time is that our gravel fill provides secondary insect relief benefit to them,” he said.
“You see a lot of caribou in the oil fields standing on the gravel pads with their noses down in the gravel to protect them from the insects’ harassment early in the season. They have learned that there are fewer insects up on this gravel fill. It simulates coastal beach areas or gravel bars that they normally use for insect relief. So there is a learned behavior going on,” Joyce said. “Remember that the herd was growing in the mid-1980s, so there are four or five generations or more of caribou that have grown up with Kuparuk. They’ve grown up with pads and pipelines and traffic, and there is a learned behavior and an adaptation, and I think there is some influence in what we currently see in terms of cause and effect on the caribou populations.”
Monitoring the caribou over 30 years with the help of computer technology has enabled the oil companies to adapt their operations to successfully coexist with the Central Arctic herd.
Among the lessons the operators have learned: Keep pipe up off the tundra; try to minimize number and location of roads and try to not place them perpendicular to caribou movement patterns — try to go parallel as much as possible; and keep traffic down and control it during calving season. Ramps can be beneficial in key locations, but probably more important is giving the caribou space between pipes and roads.
Government has important roleBecause the Alaska Department of Fish and Game is ultimately accountable to the public for the welfare of the Central Arctic herd, the agency scrutinizes any influences on the herd’s sustained viability, and makes appropriate recommendations to land management agencies and to policy makers, according to ADF&G researcher Dick Shideler.
“One of the things we feel we really need is thorough pre-development studies — but only recently have we had really good before and after data,” Shideler told the technology conference participants in 2000.
“But the bottom line for caribou calving is that the response of the caribou to the roads and facilities really does complicate what our mitigation options are for future oil fields. If they are so very reactive, it is essentially unrealistic to expect that an oil field the size of Kuparuk or Prudhoe Bay would shut down all traffic during calving, and in fact this might not be effective anyway. So we have to look at other options.”
Fortunately, the physical size of oil fields has shrunk about 80 percent since Prudhoe Bay and Kuparuk were built.
As for the shift in proportional caribou habitat use, Shideler said there has always been some calving occurring in the hills south of Kuparuk, up through an area known as the Itkillik Hills.
“I can remember doing calving surveys with Ray Cameron in the mid-80s during heavy snow years on the coast, and we had a little more calving down in the southern parts of the field, south of Kuparuk. So some of the observed shift is probably related to snow conditions down on the coast,” he said. “We do not feel that the caribou can’t physically get to the calving area. There is no impediment to ewes crossing the pipeline and roads, but it really has more to do with their behavioral response.”
Shideler said no oil development other than the tiny Badami site has occurred on the east side of the Sag River, so that area can be used as a semi-control of what has been happening on the west side of the river where the shift in calving has occurred.
“We have to remember that some caribou herds, like the Beverly herd for example, will go through major shifts in calving area almost annually. On the other hand, herds like the Western Arctic herd haven’t significantly changed its calving area in recent years, although its population has grown from 65,000 to almost a half a million animals in the past 25 to 30 years. The Teshekpuk herd hasn’t changed much either,” he told conference participants.
“From a biologist’s standpoint, trying to integrate all of this conflicting information is difficult. The bottom line is we may never know why some of these trends occur,” he added.
More study neededStill, the question of what the shift in calving areas means remains unanswered for the Central Arctic caribou herd.
Hoping to find answers, ConocoPhillips Alaska Inc. and the Bureau of Land Management provided major funding for a five-year study of cows and newborn calves in the Central Arctic herd from 2001 to 2006. The National Park Service, U.S. Fish and Wildlife Service and state agencies also provided support.
Biologists Steve Arthur and Patricia Del Vecchio sought to identify and measure the mechanisms through which oil field development might affect the Central Arctic herd, such as by reducing body condition, reproductive success or calf survival.
In an interim research technical report, “Effects of Oil Field Development on Calf Production and Survival in the Central Arctic herd,” published in March 2006, Arthur and Del Vecchio compare what happened to calves that were born in the two different calving areas, the mostly undeveloped area east of Prudhoe Bay and the area west of Prudhoe Bay that has seen increasing development since the late 1980s. In the western area, calving has shifted south since development began, though the researchers point out that it remains unclear if the shift resulted from development, increased herd size or other factors.
Arthur and Del Vecchio found that newborns from the western area on average weighed a little less and were slightly smaller than those from the eastern area, and that the differences persisted through at least the first nine months of life.
They concluded that the differences in size and mass of calves may be largely influenced by the quality of habitat and forage available to caribou cows during the calving period.
“Thus, displacement of caribou cows from preferred calving habitats may reduce fitness and survival of calves,” they wrote.
Technology advances could helpOne of the most interesting differences in this extensive study from ones conducted in the 1980s is the sophistication of the technology used today by the researchers.
Caribou cows were captured and fitted with collars containing satellite-linked GPS receivers programmed to determine their locations every five hours from May to October and every two days between November and April. Also newborn calves were captured and fitted with the radio collars every June. Location data was stored in the collars and relayed via uplink with the Argos satellite system once a week in winter and daily in summer.
Techniques used to analyze the GPS data collected in the study have not kept up with the ability to gather the data, so researchers focused on developing new techniques for better analysis.
They hope to look more closely at where caribou move and what habitat they use in relation to oil field infrastructure, they say.
Dave Yokel, wildlife biologist with the Bureau of Land Management, has said he’s looking forward to that sort of analysis. “We hope we can use the results to mitigate any impacts on the Teshekpuk (caribou) herd from development in the NPR-A (National Petroleum Reserve-Alaska),” he told an ADF&G spokeswoman. “To do that, the BLM needs to know more about the impacts on caribou of movement through infrastructure.”
Meanwhile, a 2002 photo census of the Central Arctic herd, the latest available, shows the herd’s growth trend continues. The Alaska Department of Fish and Game’s Division of Wildlife Conservation counted 31,857 caribou from photographs of the Central Arctic Caribou herd taken July 16, 2002. Groups and number of caribou were in the following locations: Katakturuk Point (115), Katakturuk Point (4,526), Canning River mouth (567), Shaviovik Delta (13,461), East channel Sagavanirktok River (1,962), Putuligayuk River (1,437), Sakonowyak River (3,299), Beechy Point (3,499) and Kaverarak Point (2,991).
“We located groups by radio-tracking collared caribou from a small fixed-wing Piper PA-18 aircraft and took photos of the groups using a 9-inch aerial mapping camera mounted in the belly of a DeHavilland Beaver aircraft,” according to ADF&G researchers.
The CAH increased from 26,128 caribou in 2000 to an estimated minimum of 31, 857 caribou in 2002, reflecting an annual growth rate of approximately 8.5 percent.
“Parturition rates, late June calf-to-cow ratios, and fall calf-to-cow ratios were good in 2000 and 2001 and mortality rates also were low. Thus, it was not surprising that the CAH increased,” the ADF&G said.
Though state biologists planned to count the herd every two or three years, they said no new census has been possible in recent years due to smoke from wildfires and cloudy weather.