Mountain Caribou: state of the research
Mountain caribou — there’s hardly a more controversial topic in Revelstoke. Logging restrictions, snowmobile closures and recent moose culling in the region — and the possibility of wolf culls are all good topics of conversation if you want to get people riled up.
I came across University of Alberta PhD candidate Rob Serrouya at a city council meeting early in 2012, where he was presenting on a multi-stakeholder plan to create a caribou maternity pen near Lake Revelstoke (a notable example of several groups with adversarial histories working together). He’s the lead researcher with the Columbia Mountain Caribou Research Project, and has been based in Revelstoke for years, leading researchers on field studies and collaborating with several government agencies and organizations.
Serrouya commented to council that he’d made a studied effort to stay out of the media spotlight, so I had to speak with him to get my question answered: What’s causing mountain caribou decline and what more should be done to turn it around before it’s too late? I had a good idea, but there’s so much conflicting, politicized information on the subject that it’s hard to discern an evidence-based answer.
I sat with Serrouya for two interviews and waded through several academic papers and a helpful slideshow.
Here’s my understanding of his research, including very recent new studies. I’ve simplified to the point of over-simplification in an effort to create a narrative — I assume we both understand real life is more complicated.
Mountain caribou (an ecotype of woodland caribou) are in decline regionally due to habitat change, driven by logging and a warming climate over recent decades, both of which make it easier for moose and deer to proliferate. Logging has reduced and fragmented caribou habitat, but more importantly created much more moose habitat.
The moose live in valley bottoms, locally along Lake Revelstoke and its tributary valleys. The pristine, pre-logging valley could only support a limited number of moose — old growth isn’t their forte.
Logging has created much more early-seral forests (cutblocks and the like), which are good moose habitat, causing their numbers to proliferate. With them came more predators, including wolves and cougars.
More wolves and cougars around mean more caribou are killed as a result. A 2011 study Serrouya and other researchers conducted showed caribou killed by predators weren’t malnourished. They weren’t being caught by predators because they were weaker, slower or taking more chances when foraging. This is more key evidence showing that habitat loss destroying mountain caribou food sources (such as that lichen that hangs from trees that they eat in winter) isn’t a primary driver of their short-term decline (although habitat fragmentation and loss of old-growth forest are important factors in the long-term decline).
Many steps have been taken over the years to help stave off mountain caribou decline. Lots of habitat has been protected from logging and other activities. There have been recreational restrictions on things like snowmobiling, heli-skiing and other activities. Trans-location from bigger to smaller herds is underway elsewhere in B.C. A maternity pen designed to protect newborn calves is set to start possibly next year.
Moose populations have been controlled. In 2003 there were about 1,600 moose in the Lake Revelstoke and tributaries area. That’s been reduced to just under 500 now by issuing more moose tags to hunters. Just decades ago there were fewer than this now-reduced number — moose populations can explode quickly.
But will it be enough?
No, Serrouya thinks (and hello more controversy). Some herds have been reduced so much that their extirpation is expected. Others are just hanging on at unsustainable numbers.
“If you want caribou on the landscape, you will have to do short-term, targeted wolf and cougar management,” Serrouya told me. “If you don’t, then no problem — let it go.” He said researchers can predict that mountain caribou will go extinct under the status quo scenario.
He repeats his belief several times. “It’s a short-term solution, but it’s a necessary short-term action to get through a bottleneck if your goal is to recover caribou,” he said. “You have to be clear. Nobody is suggesting eliminating predators from broad ranges. What’s being suggested is targeted removals in key spots. It’s removing the ones that are directly limiting caribou recovery.”
Wolf (and cougar) culls are a raw nerve in B.C., with a history of extreme opposition. Serrouya said the idea has been proposed a few times in recent years, but was declined (right at the top — premier and cabinet minister level).
PHOTO: The mountain caribou is an ecotype of the woodland caribou. Photo by Mark Bradley courtesy of Parks Canada.
There’s vehement opposition from some environmental groups but tacit approval from others. Serrouya takes a scientific view, saying the decision is a political one that we must grapple with on an ethical level as a society. “Society now accepts removing a cougar if it kills your pet in an interface area, but it does not accept removing cougars ... for an endangered species,” he notes. He points out Alberta and Alaska cull wolves for this purpose, and have had successes.
Another way of looking at it is the environmental consequences of inaction — over and above mountain caribou extinction.
“I think one thing that’s lacking right now is the social science aspect of it — engaging the people who are for and against [removing predators] and understanding why. And then frankly, trying to convince them what’s at stake — that if caribou go extinct, tens of thousands of hectares of old growth will [have a higher chance of going] back into [logging] rotation.”
Locally, he said removing about two wolf packs that overlap with caribou herds then monitoring success or failure would be the test.
I pointed out the history of wildlife management is subject to the rule of unintended consequences and littered with spectacular failures. “But it’s also littered with spectacular successes,” Serrouya countered. “We can’t just pretend that natural regulation is going to take over, because we’ve pushed things so far we have to intervene. Some of our interventions have been very strong and very successful.”
I embarked on this story with an interest in the mountain caribou research, seeking answers (what’s driving decline) from an informed, scientific perspective. I’ve provided my best, simplified explanation, and emphasized a short-term recovery solution (which was part my, but also Serrouya’s emphasis). In the process, a controversial story got even more controversial. No wonder Serrouya avoids the media spotlight.
While the focus on the short-term question of a predator cull is a societal preoccupation; Serrouya emphasizes a combination of protecting and restoring habitat, managing ungulates such as moose and White-tailed deer, maternity penning as well as small scale, short-term predator management.
Serrouya just returned from the North American Caribou Workshop 2012 held from Sept. 24–28 in Fort St. John, where he presented research findings similar to what’s stated above. His audience was North American and international caribou experts. “There was broad agreement on the factors limiting caribou recovery,” Serrouya said of the “remarkable consensus” amongst experts at the conference. He likened this consensus to another scientific debate: “It’s been growing in the last 15 years. It’s like climate change. In my mind, it’s totally analogous. We have dissenters, but we have a weight of evidence that points towards predation being the short-term, habitat and climate being the long-term.”