Stressed bat species could threaten MN pipeline

Northern long-eared bat
Northern long-eared bat in a cave near State College, Pa.
Brandon Keim / Creative Commons via Flickr

As the snail darter did decades ago, a species of bat in northern Minnesota may pose a major obstacle to a controversial construction project.

The proposed Sandpiper oil pipeline, intended to carry crude from the North Dakota oilfields to Superior, Wis., would run for 150 miles through the habitat of the northern long eared bat, a potentially endangered species.

If the federal government were to declare the bat species endangered — which may happen soon — the pipeline project could be postponed or forced to adopt a different route. (In the snail darter case, a tiny threatened fish postponed a federal dam in Tennessee for years.) To head off that possibility, the company building the pipeline is conducting its own research and looking for ways to minimize the project's effect on bats.

"We believe this was the largest survey of northern long eared bats ever conducted in the world," said Paul Meneghini, senior environmental manager for Enbridge, the company building the Sandpiper line.

The U.S. Fish and Wildlife Service is considering the bat's status and could add the species to the endangered species list within the next few weeks. If that happens, federal law would likely force Enbridge to re-route the Sandpiper line to avoid trees where the bats roost during the summer.

With that in mind, Enbridge officials took preemptive action over the summer, financing a $5 million research project to locate those trees. After analyzing the data, Enbridge modified the route of its proposed pipeline in Aitkin and Carlton counties to give the trees a wide berth.

The Enbridge study was designed to streamline installation of the Sandpiper pipeline once permits are approved. But its research has done more than that, contributing new knowledge about the long eared bat.

The northern long eared bat first attracted the attention of the U.S. Fish and Wildlife service in October, 2013.

Rich Baker, endangered species coordinator for the Department of Natural Resources, said the species is especially susceptible to white-nose syndrome, a disease that has killed millions of bats since it was discovered in New England in 2006.

"Up to 99 percent of individuals in certain caves were killed by the disease," he said. Without much data to go on, the DNR considers the long eared bat to be one of the rarer bat species in Minnesota. But the Enbridge research suggests that the population of northern long eared bats is stronger than many scientists have supposed. The study's nets caught hundreds of bats of various species. Long eared bats were the most common, even more than little brown bats, which the DNR lists as the most common bat in Minnesota.

Northern long-eared bat
A Northern long-eared bat in the Sandtown Cave in near Batesville, Ark.
David J. Thomas / Creative Commons via Flickr

"Maybe [long eared bats] are more common than we think they are," Baker said. Before the Enbridge study, very little was known about long eared bats in Minnesota. They're difficult to study, and experts are in short supply. Enbridge hired research contractor Western Ecosystems Technology to bring in bat professionals from all over the country. One flew in from Australia.

"They really tapped out the expertise that's out there," Baker said.

Last summer the DNR did a small pilot study, but Baker said it was intended to teach in-house researchers bat-catching techniques and wasn't broad enough to draw any real conclusions.

Meanwhile, the small army of Enbridge researchers set up acoustic monitors at 301 sites across eastern North Dakota, Minnesota and Wisconsin. Bat experts listened to hundreds of hours of bat sounds recorded at those sites, noting each long eared bat echo signature.

In 72 other locations, researchers caught bats in fine-mesh nets, tagged them with radio transmitters the size of a pencil lead, and followed them back to roost trees.

Of the 174 long eared bats captured, most roosted in aspen or maple trees between Hubbard and Carlton counties. More than 97 percent were healthy, Meneghini said, and all were free of white-nose syndrome.

The Enbridge study covers only the footprint of the proposed Sandpiper. Still, the limited data goes far beyond previous knowledge.

The DNR, Baker said, has applied for a $1.25 million grant for extended research slated for July. Until then, Meneghini said, Enbridge will share data.

U.S. Fish and Wildlife officials have until April 2 to list the long eared bat as endangered or threatened, or to decide not to list the species at all. Baker expects the bat will get some federal protection, and said the decision will likely come sooner.

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