​Scientists are joining the battle over a plan to ban the use of off-highway vehicles in two ecologically sensitive parks in southwestern Alberta.

Last January, the province announced a draft plan for the Castle Wildland Provincial Park and Castle Provincial Park to preserve just over 1,000 square kilometres of mountains and foothills.

Since then, groups that represent ATV, truck and jeep drivers have protested against the move to ban them from these areas within five years.

On Tuesday, 57 scientists sent an open letter to Alberta Environment Minister Shannon Phillips urging the province not to back down.

"The decision to remove off-highway vehicle use from the Castle and restore damaged areas will contribute to the conservation of native vegetation, fisheries, wildlife, soil and community water," reads the letter.

"The science is clear that motorized use, even under controlled circumstances, has a negative impact on these natural features."

The letter is signed by scientists at the University of Alberta, University of Calgary, University of Lethbridge and other schools in Canada and the United States.

Area has been mined, logged and drilled

For years the Castle region has been mined, logged and drilled for oil and natural gas.

It is home to more than 200 species of endangered plants and animals and is considered a key link for grizzly bears that move north and south.

David Schindler, an award-winning water expert at the U of A, said he supports the ban even though he owns ATVs.

Lorne Fitch, a retired biologist, shared this photo, saying he's often seen damage like this in the Castle area from off-highway vehicle users. (Submitted by Lorne Fitch)

"I have had three hip replacements on two hips and own ATVs, yet I still support the removal of this land use as I understand the impact of even a small amount of noise and disturbance has on water and on sensitive wildlife," he wrote.

"If there are areas where I cannot walk, so be it. Protection for water and wildlife first!"

Deadline for public input extended

When the Alberta government announced its draft management plan for the parks on Jan. 20, it gave people 60 days to respond, including through an online survey. The deadline has been extended to April 19.

Since then, off-highway vehicle groups have held protests, including at the Alberta legislature and in the town of Blairmore in the Crowsnest Pass.

These groups estimate up to 1,000 off-highway riders and random campers use the Castle area on a summer long weekend.

A recent analysis found the region has a road density of between one and 3.5 kilometres per square kilometre. (CBC)

In March, the government revised its plan, including not putting it into effect in the upcoming season and allowing hunters to use trail networks to recover game.

"We still feel that we can protect the environment by maintaining proper trails," said Gary Clark, the president of a group called the Crowsnest Pass Quad Squad, which opposes the plan. "We are frustrated and angry."

Clark noted that more than $2 million has already been spent in the Castle wilderness over the years to build bridges and move trails away from streams.