Blog: How do you Help Save Endangered Caribou? Stop the Invading Moose!

Authors
Alberta Biodiversity Monitoring Institute
Resource Date:
2017

Invasive moose? You might not think of them as an invasive species, but moose and some other ungulates have exploded recently over much of the woodland caribou’s BC and Idaho range (logging and a warming climate are the most likely culprits). By themselves, woodland caribou populations are too small to warrant much attention from predatory wolves. But add in large populations of other prey species, such as moose, and you have a recipe for a booming wolf population. Lots of wolves mean more predation on woodland caribou, leading to their decline. In other words, increasing populations of moose are hastening the decline of woodland caribou by increasing the number of predatory wolves.

The researchers took advantage of changing government policies in BC to perform an experiment that compared caribou populations in two large regions. In one region, new regulations allowed increased sport hunting of moose. In the second ‘control’ region, it was business as usual, with no additional hunting. How would caribou populations respond in each region?

Over several years, caribou populations in the control region continued to decline at about the same rate as ever, and moose and wolf populations remained high. By contrast, in the area with increased moose hunting, moose populations dropped by a surprising 70%, wolves left the area at a rate 2.5 times that of the control region, and, lo and behold, caribou survival rates increased by more than 10%—enough that the caribou population stabilized. These survival figures are similar to those from an Alberta study that removed 841 wolves from the Little Smoky caribou herd over 7 years, suggesting that the less controversial practice of reducing invasive prey species can be a useful tool on the road to caribou recovery.