A  federal court judge in Edmonton has given Environment Minister Peter Kent until Sept. 1 to release his promised national recovery plan for caribou.

Justice Peter Crampton says the federal government must revisit its refusal to issue an emergency order aimed at protecting the endangered caribou in the Alberta oilsands region.

Kent will also have to explain his conclusions, Crampton wrote in a decision Friday.

The judge said Jim Prentice, the former federal environment minister, never explained why he decided against an emergency order that would protect caribou habitat, although all available science pointed to the need for one.

"Notwithstanding the substantial scientific and other evidence that was discussed ... the minister concluded that there are no imminent threats to the national recovery of boreal caribou," Crampton wrote.

"This conclusion essentially came 'out of the 'blue.' …  Accordingly, the decision cannot stand."

Groups sought emergency order

Environmental and aboriginal groups went to federal court hoping it would order emergency protection for caribou habitat under the Species At Risk Act. They also wanted him to demand the federal government file a recovery plan for rapidly declining herds.

They pointed out Ottawa has missed a legal deadline for such a plan by four years.

Crampton says that if Ottawa doesn't produce its national caribou recovery plan by September, he'll decide whether to order one.

Environmentalists suggest the partial victory in federal court will force the government to ensure its caribou recovery plan is guided by science and not economics.

"This puts the burden of proof on the minister," said Cliff Wallace of the Alberta Wilderness Association, one of parties to the court action.

"We know there's good people within government that are trying to do the right thing. It may give them extra backbone to push against the higher powers that are trying to say it's business as normal. "It's our hope this will force the department to do its job."

Some scientists have predicted caribou will be gone within 30 years. Biologists have been documenting the collapse of woodland caribou in northeastern Alberta for more than a decade.

One study says two Alberta herds have declined by three-quarters in the last 10 to 15 years. Some herds now number fewer than 200 animals.

Habitat being destroyed

Several studies blame habitat destruction. Forestry has cut nearly 110,000 hectares of habitat — almost three per cent of caribou range. As well, the area now has about 35,000 oil and gas wells, 66,000 kilometres of seismic lines, 13,000 kilometres of pipelines and 12,000 kilometres of roads.

A recent report by Global Forest Watch found an average of 75 per cent of caribou range in the oilsands region has been disturbed by fire, industry or both.

Another study from the Canadian Boreal Initiative found that caribou across the country have lost about half their historic range.   Alberta has proposed protected areas as part of a land-use plan for the oilsands region. But critics say the areas aren't in regions most important to caribou and threatened by development.