LITTLE ROCK (AP) — The former director of Audubon Arkansas testified Tuesday that a $1.7 billion coal-fired power plant under construction in southwest Arkansas poses a "tremendous" threat to the birds, fish and other wildlife in the area.

"These are pristine ecosystems and we want to keep them that way now and forever," Ken Smith told a federal judge who is considering whether to issue an injunction halting construction of Southwestern Electric Power Co.’s John W. Turk plant.

The court hearing is the latest legal wrangling over the coal-fired plant, which is expected to be completed in late 2012, barring any delays. Environmentalists say the plant will pollute the area and threaten rare and endangered birds; SWEPCO says the plant is needed to meet demand and that environmental safeguards will be in place.

The construction site in Hempstead County is adjacent to two "important bird areas," as classified by Audubon Arkansas, Smith testified. Discharge from the plant, as well as dust and chemicals generated during construction, can run off into those areas and affect the wildlife, he said.

"You cannot put a fence around that area and have an effect nowhere else," he said.

But David Matthews, an attorney for SWEPCO, pointed out that the company’s Flint Creek Power Plant in Benton County is home to an important bird area that’s particularly renowned for its bald eagles. He said environmentalists have no documented proof that construction on the new plant is hurting the environment.

In May, the Arkansas Supreme Court ruled that SWEPCO didn’t go through the proper permitting process to build the new plant. To avoid going through the permitting process again, SWEPCO said it would bypass Arkansas regulatory approval of the plant by making it a merchant plant that sells electricity to customers in Louisiana and Texas but not Arkansas.

That made Arkansas Public Service Commission permits unnecessary, and regulators in Louisiana and Texas have already approved SWEPCO’s plans for power sales there. The lawsuit by environmentalists is one of the last roadblocks to completion of the SWEPCO plant.

The hearing before U.S. District Judge Bill Wilson is expected to last all week.