Bat listing could impact state timber management

Northern long-eared bat proposed for endangered listing; could limit summer harvests

courtesy USFWS
A northern long-eared bat exhibiting symptoms of whitenose syndrome. While the disease has yet to show up in Minnesota, researchers say it
Marshall Helmberger

REGIONAL— Could a bat-killing fungus significantly impact Minnesota’s timber industry? That’s the question as state, federal, and local officials contemplate the likely effects of the proposal by the federal Fish and Wildlife Service to list the northern long-eared bat as an endangered species.

The public comment period on the proposed listing ends Aug. 29, but it already appears very likely that the FWS will officially list the bat as endangered when it issues a final decision, due no later than April 2 of next year.

The FWS announced its proposal just last October, in response to concerns that the bat, which ranges across a wide swath of North America, faces possible extinction as a result of the spread of whitenose syndrome, a deadly bat disease caused by a fungal infection during winter hibernation. The disease was first documented in a New York cave in 2006 and it has since spread rapidly through the eastern half of the United States, where it has already decimated some bat populations. The long-eared bat is among the most vulnerable to the disease, according to Rich Baker, with the Minnesota Department of Natural Resources. “In the East, up to 99 percent of long-eared bats have died from it,” said Baker. “It’s a plague.”

So far, no bats in Minnesota are known to have contracted whitenose syndrome, which is named for the whitish “fuzz” that grows around the muzzle of infected bats. Two bats from the Soudan Mine tested positive for the fungus that causes the disease in 2012, although researchers have found no other positive results since then.

Yet wildlife officials say it’s probably just a matter of time before the disease shows up in the state, and they expect it to devastate bat populations when it does arrive.

While the DNR has occasionally opposed federal listings, that’s not the case with the long-eared bat. “This listing is definitely warranted,” said Baker. “It’s the regulatory reaction on the part of Fish and Wildlife that concerns us.”

Initial guidelines raising concerns

The FWS proposal to list the long-eared bat came with interim guidelines that are supposed to provide protection for the bat until the agency can issue a final decision. The guidelines are merely advisory at this point, but could have the force of law assuming the bat is formally listed next year.

FWS officials say those guidelines are designed primarily to protect the bats in their maternity roosts. Like a number of bat species, long-eared bats gather in small colonies to raise their young, with each female giving birth to a single pup. These colonies are usually established underneath loose-fitting bark on dead or dying trees. Because the young bats can’t fly for 3-5 weeks after birth, they are particularly vulnerable at this stage to disturbance, such as logging.

For now, to prevent such disturbance, the FWS is recommending that foresters inspect any and all trees, larger than three inches in diameter, that are scheduled for removal within the bat range between April 1 and Sept. 30.

State forest managers all across the bat’s range, (which includes much of the eastern and northern U.S.) say that’s just not possible. “Given the number of trees removed annually throughout the state, the recommended surveys are impractical and unrealistic,” wrote DNR Commissioner Tom Landwehr in a July 3 letter to the FWS and to the state’s congressional delegation.

Fish and Wildlife officials don’t necessarily disagree, and they are working with wildlife officials in Minnesota and elsewhere to learn more about a species of bat that, up until now, had rarely attracted the interest of researchers.

According to Phil Delphey, a Fish and Wildlife Service biologist based in St. Paul, the recommendations issued to date are based on research conducted on a different tree-dwelling species, the Indiana bat, which has been listed as endangered for more than 40 years, and has been the subject of far more research than its long-eared cousin.

But the research effort in Minnesota is quickly ramping up, according Sue Catton, Superior National Forest biologist. The Forest Service and the DNR teamed up on two pilot studies earlier this summer to capture and radio-tag long-eared bats on the Superior and at Camp Ripley. Researchers used mist nests to capture 29 long-eared bats, and glued tiny radio transmitters to the backs of 12 female bats.

The transmitters don’t stay on the bats for long. “They pretty quickly groom them off,” said Baker. But in the meantime, they can lead researchers to their roost sites, and that can help biologist better understand the bat’s habitat needs and when they are actively raising their young.

Biologists hope to learn more about the types of trees that long-eared bats prefer and to better determine the period that the young bats are most vulnerable. Right now, the FWS is recommending surveying timber harvests for six months of the year. Researchers would like to narrow that down, possibly to a period of six-to-eight weeks, but they don’t have enough information at this point to justify that.

“That’s one of the dilemmas,” said Baker.

While this year’s study was small, a much larger effort is planned starting next year, with funding from the Legislative and Citizens Commission on Minnesota Resources.

“We’re working as quickly as possible,” said Baker.

Minnesota’s spotted owl?

The Associated Contract Loggers and Truckers Association has already compared the bat to Minnesota’s version of the spotted owl, which significantly curtailed the logging of old growth timber in the Pacific Northwest in the 1990s. But the FWS’s Delphey said it may not be an apt comparison, in part because it was habitat loss that was the primary threat to the spotted owl.

In this case, it’s a disease that the bats contract while hibernating in caves and underground mines that is threatening them with extinction, rather than a loss of habitat. Even so, said Delphey, if the bat population falls to a critical level, even the loss of a handful of maternity sites during the summer could further imperil the species.

That’s why biologists are working quickly, while the bat is still relatively common in Minnesota, to more precisely determine its needs. If there’s one thing that researchers already know, it’s that if and when whitenose syndrome takes hold in Minnesota, the long-eared bat population could all but disappear in a matter of a few years. “If we get to that point,” said Delphey, “the loss during summer roosting could actually threaten the species’ survival.”

In that case, DNR officials worry that the bat could effectively shut down state, federal, county, and even private timber management during the summer months. “If these measures were applied to all forested lands, they could impact hundreds of thousands of landowners managing their forests and have a crippling effect on our forest product industries,” stated Landwehr and several other Midwestern DNR directors in a recent letter to the FWS.

It’s too early to predict such an outcome, said Delphey.

“We’re trying to be as responsive as possible to those concerns,” he said. We’ve talked with the Forest Service and the DNR quite a bit, and private forestry folks,” he said. “We’re trying to keep the lines of communication open.”

Early findings

While research on the long-eared bat is limited, initial survey work completed last year on the Superior National Forest suggest that the bat may be quite common in the area. Using mist nets at night, researchers captured a total of 34 bats over nine nights of sampling, near Ely. Of those, 13, or 38 percent were northern long-eared bats, while the remainder were a related species, commonly called the little brown bat. That species is also highly susceptible to the effects of whitenose syndrome.

Through the use of radio-transmitters, the researchers found three maternity roosts in the cracks or crevices of live aspen, and four additional roosts in dead aspen or in white pine. Researchers say more data is needed in order to draw more definitive conclusions about the roosting behavior and preferences of the bat.


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