Beaver making an Arizona comeback

54c0017bc831e.image — A beaver lodge built into the bank of the San Pedro River indicates the presence of the aquatic rodents, which were reintroduced to the river in 1999. About 50 beavers inhabit the San Pedro National Conservation Area.

“A hundred-and-fifty years ago, it was called the Beaver River because there were so many beavers,” said Dutch Nagle, former president of the Friends of the San Pedro River, an organization that promotes the conservation of the river.

Thanks to reintroduction efforts by the Bureau of Land Management beginning in 1999, an estimated 50 beavers now roam the waters of the San Pedro. The beavers have built dozens of dams that slow the river’s flow and create ponds. Along with raising the water table near the river, the slack water provides increased habitat for a variety of plant and animal species.

One of the species that prospers from the beavers’ tireless dam-building is the lowland leopard frog. “Historically, I’m sure there was a very close relationship between beavers and leopard frogs,” said Mike Sredl, who leads the ranid frog projects for the Arizona Game and Fish Department.

Along with environmental factors such as tree density and the availability of food, beaver behavior can have a significant impact on the number of birds along a river.

“The beaver contribute most in defining how many birds are in an environment, and the reason for that is they change the environment,” said Van Riper, who is the co-author of a study that examines the effects the reintroduced beavers have had on various bird species.

Great work from our beaver friends on the San Pedro! It is lovely to read about the difference beaver can make – especially in arid land. Of course the article takes time to whine a bit about how there are also more bullfrogs and non-natives but I don’t think anyone really takes that seriously anymore. I know I don’t. It’s like saying we shouldn’t repair our roads because it makes it easier for thieves to get away from the police.

The thing we want matters infinitely more than the thing we don’t.

In case, you, like me, are dying to look at Van Riper’s bird study, the whole thing is available here. It’s a very interesting read, but I think overly cautious about the benefits of beavers. For example, they note they “can’t conclude whether” the increase in biodiversity near beaver activity represents beaver effects, or just beaver CHOOSING richer habitat to settle in.

(Sheesh. Because you know how those lazy opportunistic beavers are – always picking the nicest neighborhoods to move in. Grr.) The report generously concludes that at least beavers did not appear to make anything worse.

Beaver reintroduction did not appear to have detrimental effects on any species of conservation concern and, in fact there was evidence that a breeding bird community is more abundant and more diverse where beavers were present.

Mighty white of you, I’m sure.

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Now for an unmitigated treat, check your insulin levels first, because this is too sweet to be believed. The kit is at Point Defiance Zoo in Tacoma WA and her grape-testing made TIME this morning. Her name is Hazel.