Sorry, but science doesn't take sides

February 16, 2009 

Why is science starting to sound so much like religion

With some regularity now, especially when it comes to environmental issues, we have politicians and interest groups engaged in heated arguments about who has God -- er, science -- on their side.

Often lost in all of this is the science itself.

The latest case in point comes in the skirmish between the environmental group Defenders of Wildlife, and Gov. Sarah Palin and her supporters in the Alaska Outdoor Council.

Palin and the AOC say they have the science to support predator control in Alaska.

Defenders say oh, no, no, the science is with them.

The truth is that they are both right, and they are both wrong.

Here is what we know about the science of predator control vis-a-vis large mammals:

• Remove all predators and there will be more prey -- at least in the short term. There is no debate about this. If you are reading this column in Anchorage, you can look out your window and see a good case study.

Anchorage is full of moose because predators here are few. Wolves are absent. Grizzly bears get into town now and then to kill a few moose, but probably not so many as motor vehicles. The latter kill 150 to 200 a year, but few of those are calves. So moose calf survival is generally good.

This is not the case everywhere in the state. In many areas of the Bush, grizzly bears, black bears, wolves and even coyotes gang up to kill huge numbers of moose and caribou calves every spring. Removing predators will give those calves a chance to survive. There is no argument. Science here is clearly on the side of the governor and the AOC.

If you rid Alaska of most wolves and bears -- if that is your idea of wildlife management -- you will have more moose, caribou and Dall sheep.

That's a big "if." Even most of the backers of predator control say they want to maintain "healthy" populations of wolves and bears. If that is another goal, then the science of predator-prey management gets a whole lot trickier.

• Most Alaska predators and prey exist in what are multiple predator-prey systems. Often there are wolves, grizzly bears and black bears preying on moose, caribou and Dall sheep. And until you know which predators are feasting on which prey, it's hard to know which predators to kill. There are documented studies in Alaska wherein wolf-control programs were instituted, a whole bunch of wolves were killed and still moose populations remained low. In the best known of these, further research determined the wolf extirpation didn't work because the real problem was with grizzly bears killing nearly all the moose calves every spring.

Science is on the side of Defenders and high-visibility spokeswoman Ashley Judd when she argues the state in some cases lacks the evidence to support the idea that slaughtering a bunch of wolves will mean more moose. Randomly killing large numbers of wolves won't lessen the odds of survival for moose, but in reality it might not change it enough to make a difference either.

Some of the wolf control programs could end up doing little or nothing to help prey. We could end up killing wolves just to kill wolves, because the science here can get really tricky.

• The number of predators isn't the only factor in prey survival. There is another big player in the game. Depending on your belief system, you can call this player God, Mother Nature or even climate change. Weather is a pivotal, sometimes overlooked player, in some of the Alaska ecosystems where predator control is now hotly contested.

Game Management Unit 16 across Cook Inlet from Anchorage is one of these areas. Once again this year, the snow behind Mount Susitna is up over your head. Moose can't survive long in snow that deep. They need to be able to get around to find browse or they starve to death. Unit 16 has, in recent times, been plagued by moose-killing winters. It doesn't matter how few predators there are if deep snows kill nearly all the moose.

In this regard, it is worth noting that Alaska, in general, is a great place to be a bear. They are a lot like tourists. They come out in the summer when the land is green and full of life, and they retreat to safe sanctuaries for the winter when the land is cold, snowy and generally inhospitable, which brings this around to the last key bit of science.

• Alaska has been managing salmon for maximum abundance for decades now. Fisheries managers for the Alaska Department of Fish and Game have done a superb job of rebuilding weak salmon runs and putting a lot of fish in Alaska creeks and rivers. These fish feed bears.

Nobody knows exactly how many bears there are in Alaska, but the science clearly says that if there is a lot of food for bears, you will have more bears than if there is little food for bears. We've been feeding bears a lot of salmon for years, and it is clear that in most areas of the state -- including Anchorage -- we now have a lot of bears.

The bears come out of their dens every spring hungry. The salmon, unfortunately, are still a month or more away. So the bears look around for something else to eat. Moose in many areas of the state suffer as result. So now there is talk of "bear control" programs to reduce bear predation.

I hate to sound like one of those commercial fishermen whining about "over-escapement," but how come no one ever talks about a "salmon control" program to reduce the ecological carrying capacity for bears

Or would that just cause some group like Trout Unlimited to jump into the fray proclaiming, "there's no science to support salmon control."

Of course not. Science only explains how the world works; it doesn't support or oppose anything. It simply provides the information to help us decide how to behave. We then sort out differing opinions about acceptable behavior through something called "politics."

Let's not confuse that with science. It's really a lot more like religion; it's pretty much all about your belief system.


Find Craig Medred online at adn.com/contact/cmedred or call 257-4588.

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