Part two of an ongoing column and story series exploring the Revelstoke Caribou Rearing in the Wild maternity penning plan.
I was asked to provide a scientific background on the maternity pens. As I thought about the problem, it became clear that like any management challenge, it comes down to a mix of science and values – what people want. The maternity pen should only be pursued if people want it. So here’s some background to help inform people.
Any time we discuss mountain caribou, it always comes down to the three related recovery options:
1) reducing food for moose and deer (in other words, protecting old forest habitat for caribou);
2) reducing alternate prey (moose and deer);
3) reducing predators.
Focussing only on option one won’t solve the problem because shrubs will be around for decades. Shrubs grow after trees are logged, which then grow moose and deer, which in turn grow wolves and cougars. Option two – reducing alternate prey – also on its own, is sketchy because predators might switch to caribou.
Finally, Reducing predators (option three) without addressing options one and two means that predator control would have to go on indefinitely, which many people consider unethical and is not really accepted in B.C.
The ‘mat’ pen is basically related to option three because it would reduce predation on calves.
Will mat penning work? Consider that calves in Alaska and Northern B.C. die most often during the first month of life, usually from predation.
Penning worked well in the Yukon, but not so well for the Little Smokey herd in Alberta.
In the Yukon, wild calves had a 15 per cent survival, whereas calves that were in the pen for about a month had 74 per cent survival (four months post-release). All 96 pregnant cows birthed healthy calves, suggesting that female body condition and stress were not problems. Obviously we’re trying to focus on the things that worked well in the Yukon and not repeat the mistakes from Alberta. And here’s a bit more on the science part – see the graph of what we could expect from penning. Penning would help reduce the decline if half the females are penned, just before and after calving – then they are let go.
What I conclude from this little math exercise is that penning alone won’t solve the problem. It’ll help, but a mix of all the options will be needed, at least in the short term.
From a personal perspective, there are two things I like about this project. First, from the 10 years of land-use planning I’ve worked on, I haven’t seen people with different values get along so well. We’ve brought people together who don’t normally hang out. The reason people came together is because penning is a way of reducing predation on calves without having to kill predators, or to reduce more moose, or even to protect more habitat. If it works, it’s a win-win.
The second aspect is the chance to work with students to take them crashing in the bush to learn about wildlife, collect lichens for the pen, and do some computer work to show how math can be used to help solve real-world problems (the graph is an example to help make decisions). Let me know if you’re interested.
Rob Serrouya is a wildlife biologist contracting for the BC Ministry of Forests, Lands, and Natural Resource Operations, and for the Alberta Biomonitoring Institute. He’s also finishing his PhD at the University of Alberta.
The Revelstoke Caribou Rearing in the Wild project (@RCRWSociety on Twitter) is competing for $100,000 through a social media contest sponsored by Shell Canada. Please visit www.fuellingchange.com for competition details and how you can help make a difference.