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Musings on the Excellence of Ursine Public Relations

Science isn't moving nearly fast enough to keep up with politics. That, at least, is the conclusion I came to after reading a technical paper in the journal Ecology.

Written by Francois Messier, a member of the biology department at the University of Saskatchewan in Saskatoon, the paper reviews a great many publications on and near the subject of its title: "Ungulate population models with predation: a case study with the North American moose."

You can probably figure out why the title made me think of politics. Just in case you've been in Bora Bora or Tashkent for the past few years, let's say simply that predator control has been a subject of heated debate in Alaska's political circles. A bill recently signed into law---Senate Bill 77---codifies one aspect of predator control, by formally adopting the opinion that human consumption is the highest and best use of game animals.

That assumption of what constitutes best use is a political one. It represents a societal decision and a value judgment, one outside the present realm of the natural sciences. However, biologists and ecologists should be ready to set forth the actions required in order to provide maximum sustainable and huntable numbers of game animals. Those should be straightforward matters of wildlife management, and we've been managing wildlife for decades.

But to do it right, we might need several more decades of study. Messier's report on moose, for example, points out as many questions as answers on what affects moose numbers, though quite a lot is known. The quantity and quality of available food comprise the first control; even with no predators and no human hunters, moose numbers can't keep growing forever because the animals would run out of food.

And predation by wolves surely affects the moose population. Messier found that if the food supply is adequate, the moose population theoretically would achieve a maximum of two animals on each square kilometer of range if no wolves were present, while it would stabilize at the equivalent of 1.3 moose per square kilometer if wolves were present.

Add bears as an additional predator, and the moose population could stabilize at a much lower density, perhaps one animal for every 5 square kilometers. It turns out that bears are extremely effective at keeping moose numbers down because they are skilled at catching and killing calves, even when moose are found at relatively low densities. Yet, in general, "predator control" has been presented in the media as if it were synonymous with "wolf control." Maybe I've been inattentive to the details, but I haven't seen any suggestion for aerial hunting of grizzlies. How come bears with a taste for moosemeat have escaped the public assault that's fallen on wolves?

I suspect bear eradication would annoy the tourism industry even more than wolf control has, but the so-far imperfect evidence does suggest that removing bears may be necessary for maximizing moose numbers, as the law evidently requires. (I read somewhere that chief predators on young mountain sheep are golden eagles. I would not envy any game manager who had to put up with the hue and cry that would arise if declining sheep numbers made eagle control a priority.)

A way around the unpleasant necessity of killing predators might lie in distracting them with different prey. Research that Messier cites indicates that sometimes the presence of tasty but more easily caught animals, such as deer or wapiti, enables the coexistence of wolves with more moose than usual. Sometimes that doesn't work out so well for the moose, however. Increasing numbers of wood bison in the Northwest Territories have permitted an increased number of wolves--but the wolves find moose easier to hunt, and so moose numbers are going down.

Food, bears, alternative prey: a lot remains to be learned before moose management becomes a straightforward matter---if it ever does.