More Moose, More Wolves, More Predation.

Scientific papers are often difficult to decipher unless you have a background relating to the topic, and even then, with all the data sets, formulas, and graphs it can still be difficult at first read. The information held in some of these papers is often eye-opening and, in most cases, will make the person reading it think deeper about the subjects. In this case, a paper regarding the removal of moose, in turn, meaning less wolves being removed for woodland caribou conservation, did that for me. When I first read the title, “Restoring historical moose densities results in fewer wolves killed for woodland caribou conservation” in a new research study published in 2024 I thought, that doesn’t make sense to me. How would removing one prey source help another prey source? After a couple of reads it made a lot more sense to me.

To summarize this research paper, I’m going to exclude the formulas, graphs, and deep scientific data and let you dig into those if you like these sorts of details. The new research showed that increased hunting designed to reduce moose density to a historical level resulted in fewer wolves being removed as part of recovery actions for the endangered southern mountain caribou population. The results suggested that policies that allow for higher than historical moose densities in caribou ranges will result in removing a greater number of wolves to achieve caribou conservation and recovery objectives. Unless moose, the primary prey, are harvested at a level that decreases their numbers substantially, more wolves will need to be removed to avoid caribou extirpation, until the onset of old-growth forest habitat conditions results in reduced moose abundance. Moose management policies that allow increasing moose abundance in association with wolf removals are anticipated to make ongoing wolf removal objectives increasingly difficult to achieve, thereby challenging caribou conservation.

Lead scientist on this new study, Dr. Michelle McLellan says, “Elevated moose abundance thus has the potential to cause wolf populations to rebound quickly each year following reductions, suggesting a possible link between moose abundance and the number of wolves killed for caribou conservation”. What is suggested here in the paper’s abstract is that, if you have more moose, there will be more wolves and, in turn, more predation. Pretty simple concept when you think about it. Eventually, when the wolves eat up a lot of the moose, they will have to look elsewhere for food. As hunters, we know the importance of population balances. We know that more of one thing may certainly mean less of another and ever since humans have been here on earth, we have meddled in wildlife population dynamics and the reality is we need to continue doing that or we risk losing major populations of wildlife across the world. This is often a hard sell to the anti-hunting, anti-trapping type people (I’ll just refer to them as antis from here). Anti’s feel that we should leave wildlife alone, let them be, and that we should not try and control nature. This is especially true when it comes to wolves, people love wolves, and they get very passionate about them. When it comes to culling wildlife for population reasons, predators often take the first hit. Everyone says remove the predators and the prey will flourish, resulting in the anti’s fighting back for the protection of predators and we’ve seen this repeatedly. What this paper is suggesting, and determined, is that if the prey are reduced, in conjunction with the predators you will need to remove fewer predators in the future. Less prey, less predators, less predation.

The authors of this paper used a unique management situation in British Columbia and Alberta where lethal wolf removals were conducted across specific southern mountain caribou population ranges and, in some places, moose populations concurrently reduced via liberalized hunting. What they found was that after controlling for habitat quality, wolves removed per square km were 3.2 times lower in areas with reduced moose density than in those areas without reduced moose density, resulting in the suggestion that policies that do not reduce or stabilize moose abundance will result in the removal of more wolves to help the endangered caribou population.

A comprehensive investigation has recently identified that wolf removal as the only action, when applied in isolation, consistently increased caribou population growth. We have been employing this strategy for years now, think back on Frank Glaser and his famous .220 swift. But with more modern thinking we can now apply other options in conjunction with this strategy and obtain greater results in population gains, be it penning, supplemental feeding, or moose reductions. Wildlife scientist, Scott McNay noted that direct predator removal reverses caribou decline because there are fewer predators to kill caribou, releasing populations from top-down limitations. Top-down predation is a process in which predators at the top of a food chain affect the abundance of organisms at lower trophic levels. Although this is often seen as a success, it also means that depending on other ecological factors such as habitat quality, it can mean an increase in the abundance of moose and deer.

How is this an issue for caribou conservation? Several researchers have suggested that higher moose and deer populations may accelerate the recovery process of predators and in some cases increase local predator density following a period of intensive predator removal. In addition to wolf removal by people, reducing moose and deer, where they are the primary prey, should impose a bottom-up control on wolf populations leading to fewer wolves and constrained wolf recovery. However, primary prey reductions must be done with sufficient intensity to overcome any density-dependent recruitment and survival of remaining wolves.

All of this of course comes with its ethics and controversy across the various sectors of society. Things such as moose reductions that increase meat and subsistence harvest opportunities may be favorable in some instances but the drastic changes to populations may have negative effects on Indigenous Peoples and licensed hunters in the long run. Other things such as who gets to participate in additional hunting seasons, or when hunters or professional sharpshooters are used are topics that can prove to be very controversial and that need to be factored into the removal strategy. In the study led by Dr. Michelle McLellan, two companies used aerial removal via helicopter and rifles to reduce wolf populations, which continued until wolf numbers were < 1-2 wolves/1,000 km2, making locating additional wolves difficult. Moose removal was achieved by increasing permits for hunting until the population was reduced enough to align with the expected moose density for the areas before they were heavily modified by forest harvesting. Ongoing male and antlerless permits maintained the density at a desired level.

When it comes to the removal of an animal from the landscape there will always be controversy from one side or another. It’s difficult to please everyone when it comes to issues with ungulate populations and predators. Wildlife managers have a hard job to do to achieve a balance, both in nature and in politics. I think people need to realize we’ve had a hand in wildlife population management for centuries in one way or another and we need to continue it to have animals on the land for future generations.