Large-scale caribou study by Revelstoke researcher highlights ‘adaptive management’

A new hope for caribou recovery?

File photo: Caribou are released into a maternal pen as part of the Revelstoke Caribou Rearing in the Wild penning project, which is located on the west shore of Lake Revelstoke. Photo: Revelstoke Caribou Rearing in the Wild/file photo

Editor’s note: This is an excerpt of a longer story on the ongoing woodland caribou issue that was published in the June 2019 print issue of Revelstoke Mountaineer Magazine, which is now available across Revelstoke. We’ve also included a link to a long-form interview with Dr. Robert Serrouya on the Revelstoke Mountaineer podcast. The story is primarily based on a new study entitled, Saving endangered species using adaptive management, that was published in Proceedings of the National Academy of Sciences of the United States of America. Serrouya was the lead researcher among a team of scientists who worked on the paper. On a personal note, I’ve spoken with Dr. Serrouya over the years on the topic of mountain caribou and consider him likely the most knowledgeable person on caribou in Revelstoke; he’s spent years doing caribou studies in the mountains around Revelstoke, earned his doctorate in the process, and has also been engaged at a high level with governments and other organizations working on the caribou conservation file. At a time when the subject is contentious, political and polarizing, speaking with Rob was an opportunity to approach the subject from a different viewpoint — a scientific lens. If you’re invested in the caribou issue, take the time to follow the link to read the study, and listen to the long-form interview. No matter where you are on the caribou issue spectrum, you’ll likely learn something that will assist your understanding. Because Dr. Serrouya was in Norway studying reindeer, we didn’t connect until just before print deadline, so as a result the story I banged out while on deadline doesn’t do as much justice as it could to the complex subject matter, which is why I encourage you to read the fairly easy to read study and listen to the interview.  — Aaron Orlando

Large-scale caribou study by Revelstoke researcher points to ‘adaptive management’

The endangered mountain caribou have been the subject of countless studies over the past decades. Usually, they are smaller studies aimed at answering discrete questions. What do they eat in summer? What eats them? What are their causes of mortality? What is a particular herd’s range? How does helicopter traffic affect their stress levels? That sort of thing.

A new research paper published by a Revelstoke scientist in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) builds on the foundation of many studies to suggest a new, comprehensive approach to recovering mountain caribou.

Dr. Robert Serrouya led a team of biologists to create the paper entitled, “Saving endangered species using adaptive management.”

The large-scale study of woodland caribou took place over a 90,000 square-kilometre area in B.C. and Alberta, including the herds around Revelstoke.

The study looked at the effects of different recovery options for woodland caribou, such as reducing predator numbers, preserving habitat, trans-locating caribou to other herds, maternity penning, and removing other ungulates — such as moose and deer — that support increased predator populations.

Listen: In this long-format interview, caribou researcher Dr. Rob Serrouya discusses the results of a large-scale study of woodland caribou, including in the Revelstoke area, that looked at ‘adaptive management’ as a tool for aiding recovery. His study was closely intertwined with ongoing government caribou recovery efforts and provides insight into ongoing caribou recovery actions on the ground, as well as potential future options. Click play to listen.

The study found that deploying multiple tools at once led to the greatest increase in caribou herd numbers.

“The continental scale of forest alteration and extended time needed for forest recovery means that relying only on habitat protection and restoration will likely fail,” the paper states in its abstract. “Therefore, population management is also needed as an emergency measure to avoid further extirpation. Reductions of predators and overabundant prey, translocations, and creating safe havens have been applied in a design covering >90,000 [square kilometres]. Combinations of treatments that increased multiple vital rates produced the highest population growth. Moreover, the degree of ecosystem alteration did not influence this pattern.”

This graphic from the paper, Saving endangered species using adaptive management, published in March in the Proceedings of the National Academy of Sciences of the United States of America shows population change rates for woodland caribou groups. Image: Proceedings of the National Academy of Sciences of the United States of America/Creative Commons licence

The team working on the study included several B.C. government scientists, which allowed the research project to piggyback on the existing efforts of the B.C. government to recover caribou. By contrasting the effects of the various tools, including places where more than one recovery option was used, they were able to track the results. “We were simply reporting on what society and the federal recovery measures were recommending,” Serrouya said.

The results were most encouraging in the Klinse-Za area, near Mackenzie, B.C., where a combination of predator reduction and maternal penning was used. The declining herd’s numbers reversed, and began to increase at a rate of 14% by the end of the study.

A focus on habitat recovery — specifically halting old-growth logging — has been the focus of most environmental groups. Serrouya said that habitat preservation is key to the long-term survival of the species, but that takes time to achieve. It takes decades for a clearcut forest to return to suitable caribou habitat, but it does happen eventually. The caribou are suffering from the effects of well over a century of industrial disturbance on the landscape, such as logging, but the long time-frame means that some of the habitat is returning.

Most environment groups focus on habitat preservation for caribou recovery; Serrouya said that’s absolutely necessary for long-term recovery, but it doesn’t address the problem of their continuing decline.

Caribou at the Revelstoke Caribou Rearing in the Wild’s maternity pen, located on the west shore of Lake Revelstoke. Photo: Revelstoke Caribou Rearing in the Wild

“That’s the real rub. You could protect all the remaining habitat tomorrow. We could stop everything we do, but these herds here in the mountains will still decline, some of them to extinction in short order, unless you also at the same time manage the predator-prey system,” he said. “If society wants to do it, you have to reduce wolves and cougars for a short time until the habitat recovers.”

Serrouya said that the data isn’t complete, and there is a lot of variety across the province, but the rate of habitat recovery in some areas is in equilibrium with forest areas lost to harvesting.

Serrouya said that the data generated by the adaptive management study provided new hope for the recovery of mountain caribou.

“In terms of the global loss of biodiversity, caribou are the best umbrella we’ve got,” Serrouya said of the caribou’s role in the regional ecosystem. “We used to think it was grizzly bears, but it’s not. If you’ve got caribou in the forests out there you’re going to have biodiversity.”

He expressed disappointment in the way the federal and provincial governments structured their consultation plan, saying going to a public forum without concrete plans was putting the cart before the horse. “You do the science, then … you’ve got to figure out what it’s going to cost, then you go to the public after you develop a couple of categories of options, and then again, whose turn is it? It’s the decision-makers, the politicians to decide.”

Is he hopeful that we will be able to recover the mountain caribou? Serrouya noted that government management has led to increases in numbers for six different herds, and the lessons learned there can be applied to the other herds.

“I am totally hopeful,” he said. “As long as those actions are followed up with habitat recovery, then I am for sure hopeful. I wouldn’t be in the game if I wasn’t.”