Ahh, the age old dilemma that most cities spent 3 whole minutes wrestling with. Kill them? Or let them Be-[aver]? Mind you in Martinez it took 200 people at 2 meetings over 7 months to convince 5 council member, but we’re exceptional. Most places never get the message.

Take Pennsylvania for example, where they’re killing beavers to protect Old Growth Hemlock Forests. At least they had the decency to pretend to struggle with the decision. But we know better. This is Pennsylvania for petesake, where the trapper said he was only going to remove the “soldier beavers.” Remember? One of my very favorite columns EVER.

Beavers Versus Old Growth: The Tough Reality of Conservation

Conservationists know beavers perform valuable ecological services, creating important habitat through their dams and tree clearing. They’re charismatic animals. Their recovery in the eastern United States is a stunning conservation success.

What happens when those thriving beavers threaten old-growth hemlock groves, one of the most imperiled habitats in the East?

That’s the situation at the Conservancy’s Woodbourne Forest Preserve in north-central Pennsylvania. It is forcing conservationists to choose between beavers and old-growth trees.

To some, this is a no-brainer for a wildlife sanctuary: leave it to beaver.

After all, haven’t beavers been shaping the forests for millennia? Isn’t it natural?

The reality is much more complicated. If people and beavers are to exist and thrive together, sometimes tough choices have to be made.

Guess what they decide? If beavers and people are making things hard for old growth Hemlock forests, will they kill the people?

“Beavers can do a heck of a lot of good,” says Hardisky. “But they can also do a lot of damage.”

It’s easy to say that beavers should be left to their own devices. It’s much harder to say that when they’re flooding your home or farm field or local road.

“The reality is, we have to balance the beaver population with human needs,” says Hardisky. “The state can support a large beaver population, but there is a social carrying capacity – how many beavers people can live with. We manage them so there is a stable, healthy population.”

This necessitated a difficult decision:

Beavers or Hemlocks?

Ooh Ooh Call on me! I know this one!

“We have to decide what we want for the forest, not only at Woodbourne, but across the country,” says Eckley. “In this case, the beaver population is thriving. That’s a success. But beavers may not be the only consideration. I think old-growth forest is important, too. This is what we as a society have to decide. There are no easy answers here. We have to be informed and think about what we want the future forest to look like.”

I suppose if there were a real trial to decide which species should live, it would include an examination of what each species contributes. How many birds, fish and mammals depend on old growth hemlock? Versus how many fish, birds, mammals and insects depend on beavers? I wish I got to say that in court.I mean it is called the NATURE CONSERVANCY not the OLD HEMLOCK CONSERVANCY. The article makes it seem like the rising water level killing trees is ruining old growth, so I commented this of course.

Why would scientists use a false dichotomy to make a decision? In stall flow devices to regulate dam height (well researched and studied all over the hemisphere) and save the trees AND the beavers. I know flow devices work because my own city installed one 7 years ago to prevent flooding, and now because of our safe beaver-tended wetlands we regularly see otter, steelhead, woodduck and even mink in our urban stream.

Solve the problem, not the symptom.

Mr. Hardisky from PA Game Commission wrote back staunchly defending the decision:

Water control devices installed in beaver dams are usually effective in regulating water levels, but do nothing to address the problems of dwindling food supplies and direct damage to the surrounding old growth forest. In this case, you cannot have your cake and eat it too. “Saving” beavers at the Woodbourne Forest Preserve will result in additional loss of old growth trees. Population reduction was the most responsible solution to this problem. Water control devices have been used at Woodbourne in the past and will likely be used in the future to help control flooding and protect native plant communities. These devices are not fool-proof, however. Controlling water levels in beaver wetlands in conjunction with a regular, limited beaver harvest will extend the life of the beaver colony and the many benefits they provide by 10-20 years. If you do not remove beavers on a regular basis, they will eat themselves out of house and home … no food, no beavers, no environmental benefits. This was the exact scenario at the Woodbourne Forest Preserve. As the author noted in his week-long blog series, lack of human intervention can result in significant negative impacts to the environment and loss of plant communities such as old growth forests. Beavers have no significant predator other than man. It would be irresponsible for us to ignore what we have learned from sound science and modern wildlife management techniques.

To which I would point out that it’s not like beavers LOVE hemlock. They would much rather have some riparian willow, birch or aspen to munch on. Which would cost an afternoon and three busloads of boy scouts to stake into the mud, and thrive on beaver chewing and regrowth protecting the Hemlock trees for decades to come.

I’m sure Mr. Hardisky (if indeed that IS his real name! It sounds kind of like a bad melodrama…) has a reason why that wouldn’t work either.

I’ve been a bad beaver advocate. I have been so busy practicing my speech and packing for Oregon that I haven’t had time to sit down with the Pennsylvania beaver plan fully. I made it through the first ten pages and challenged the comment about beavers never stretching. I still want to correct the mistaken expectation of zero beaver mortality and beavers not having trouble with parasites. I want to set the record straight about estimating beaver populations based on the number of dams or lodges.

There just hasn’t been enough time.

Tom Venesky’s article prodded me yesterday, and maybe I’ll bring the 90 page management plan along to the conference and have everyone weigh in on the important points! Tom is a sports reporter for the Times Leader who wrote the excellent article describing how not trapping beavers can allow a wetlands to rebound and make better wildlife to trap down the line. Not exactly the point of view I usually champion, but very smart persuasion. We exchanged friendly emails and I wrote him to make sure to weigh on the new plan in his state.

His recent article highlights that part of the plan is to broaden trapping restrictions to reflect all of the state. Currently there are regions where trapping cannot occur “within 15 feet of a lodge or a dam” and in places where those rules are in place the population of beavers is stable.

The first is a regulation preventing trappers from setting traps within 15 feet of a lodge or dam. The restriction is in place elsewhere in the state, Hardisky said, and it does give some protection to young beavers and adult females because they don’t venture far from the structures.

You see why I need to go through the entire report line by line? Let’s assume that our kits never go more than 14 feet from the lodge (they do), and only pesky Dad and GQ travel more than 15 feet away from them. And then the adults get killed. Who cares for the young? What if the beavers have built a bank lodge and no one knows it’s there? What if there in a wide body of water with no dams? The statement that female beavers stay close to home is completely bogus (and bordering on wishful sexist thinking). Research tells us that female dispersers actually travel FARTHER than males in their effort to find their own habitat.

As far as maintaining healthy populations, Hardisky pointed to a study in Ontario that found when trappers remove one to two beavers each year from an area, that colony will last 20 to 30 years. If left unchecked, the beavers will exhaust their food supply and eventually move on. As a result, the dam wouldn’t be maintained and will eventually wash away, eliminating the wetlands that was created.

“Not trapping a beaver pond is a mistake because they will eat all their food supply, move on and then you’ll lose that pond,” Hardisky said. “That dam will wash out and the wetlands will drain.”

Apparently he is suggesting that killing one or two a year will prevent over feeding and the development of those pesky meadows that are formed in drying beaver ponds. I have to scratch my head at this, since we can assume four kits are born and 2 yearlings disperse every year. I can’t imagine which one or two they are trapping that keeps things stable? Mom or Dad? clearly not if the colony continues for 30 years. A couple yearlings? Most likeley, but that means there are fewer to disperse and carry beaver benefits to another area. Remember the mortality rate for dispersal is already 50%, so if you start out by killing half your dispersers you’ll be lucky if a single beaver manages to make it.

Hardisky also advised trappers to pull their sets from a location when the catch rate starts to slow down.“That’s when it’s a good idea to move on and not try to get every last one,” he said.

Wow. Apparently the beaver management policy of the great state of Pennsylvania is ‘always leave some orphans‘.