HIGHLAND PLANTATION – A northern bog lemming weighs just one ounce, and the Roaring Brook mayfly is less than half-an-inch long. Both are also rare.

The presence of the furry creature and two-tailed invertebrate, among other forms of wildlife, are threatening to topple a proposed industrial-scale wind energy project in Highland Plantation.

The Maine Department of Inland Fisheries and Wildlife recently expressed concerns about the planned wind farm’s impact on certain species in comments prepared for the state agency reviewing the developer’s request for construction permits.

The habitats of lemmings, mayflies, spring salamanders, bats and birds would be put at considerable risk, according to the report to the Land Use Regulation Commission. The lemming and mayfly are on the state’s endangered list. The salamander and eight species of bats in the plantation are all on a state “special concern” list.

The comments surprised developers, who have been working with the wildlife department for the last four years in their effort to install 39 wind turbines on ridges in the tiny community.

Developer Highland Wind LLC is operated by Brunswick-based Independence Wind, which is led by former Gov. Angus King and former Maine Public Broadcasting Corp. president Rob Gardiner.

“We were fully aware of the presence of all those animals and thought we had taken measures to absolutely protect them, and that’s why we were caught quite a bit off guard by the comments,” Gardiner said.

It’s not known whether Highland Wind can modify the project to reduce the impact on wildlife and meet permitting approval by the Land Use Regulation Commission.

The wildlife department stated in its report that the developer could take piecemeal measures to reduce the impact on wildlife but that it would not meet conditions required under Maine law.

“It’s going to slow us down a little bit because we have to stop and consider these things. We may have to back up a step to deal with them effectively,” Gardiner said. “That doesn’t really trouble us. Speed is not the issue for us. We want to get it right.”

Opponents of the wind farm, who have expressed concern about the rotating turbine blades’ impact on tourism, health and the environment, said they were glad a state agency shares some of their worries.

“This opposition we’re mounting is very expensive and time consuming and very hard on people. There would certainly be a feeling of relief if a fly brought down a king,” said Karen Pease, of Lexington Township. “Nobody wants to see anyone fail at a business, but we believe this is wrong, especially for an area like the Highland Mountains.”

Pease, a member of the nonprofit Friends of the Highland Mountains, said she worries that the state may agree to a deal to install the Highland Wind project at the expense of the animals there, in exchange for the protection of land elsewhere in Maine.

David Corrigan, a Maine Guide from Concord Township, said the department’s comments could seriously hurt the wind farm project.

“To put it bluntly, if this were anything but an expedited wind permit, this would shut down any project in the state of Maine. I don’t believe there’s another sort of development in Maine with a report like this on the table,” he said.

The report left him wondering what the wind farm’s impact would be on large game, like moose, deer, wolves, bear and bobcats. Those animals aren’t mentioned in the current report.

Marcia Spencer-Famous, senior planner at the Land Use Regulation Commission, said the developer and inland fisheries and wildlife representatives have been discussing for several years what the wildlife concerns are at the proposed wind farm site.

“If IF&W did not identify moose or deer for concern for this kind of project, there wouldn’t be a study on it,” she said.

The department has the following concerns about the site:

A series of wetlands along Witham Mountain support a population of northern bog lemmings, which the department describes on its website as “among Maine’s rarest and most elusive mammals.” They are not found in large numbers anywhere, except in Alaska and around Hudson Bay.

The Roaring Brook mayfly and spring salamander were discovered in the Stoney Brook watershed in Highland. According to information posted on the department’s website in 2010, mayflies were only found in Roaring Brook at the base of Mount Katahdin in Baxter State Park. It was believed, however, they could be present in other cold streams in the Katahdin area.

Monitoring bat activity showed the “highest recorded bat sequences for any previously proposed project in Maine,” according to the department’s report. In addition to the large number of bats, certain populations are being severely impacted by a fungus that causes white-nose syndrome and are under consideration for protection under the Endangered Species Act.

The passage rate of birds, both during the day and night, “are among the highest reported for projects in Maine,” according to the department’s report, and it’s likely many birds would be killed by turbine blades.

R.J. Mere, of Kennebunk, president of the Saco River Salmon Club and Hatchery in Biddeford and a former chairman of the Kennebunk Conservation Commission, has written about lemmings.

“I like to remind people about why these specific habitats are important, and that’s because they’re part of the biomes that feed other creatures. It’s important that we protect those,” he said. “It’s not just the little lemming; it’s all the other creatures.”

After meeting with LURC and the wildlife department, the developer will decide how it wishes to respond.

Gardiner said all development has some kind of environmental impact. The important thing, he said, is to weigh environmental impacts with the benefits of wind energy.

“LURC is ultimately making a decision between clean green energy and having absolutely no environmental impacts. They have to balance that. We’ve tried to minimize the environmental impacts. We cannot eliminate them in a big project,” he said.

He added: “Compare that to the problem of global warming caused by fossil fuels; compare that to what people in Japan are going through. It’s time for Maine to get serious about treating green energy projects as something that is desirable even though it has impacts.”