More than 1,700 people have signed a petition opposing plans to resurface a four-mile path in the Lake District with asphalt.
The path along a former railway line between Keswick and Threlkeld has been closed since December 2015.
The work is part of a wider £8m scheme to repair an area badly hit by Storm Desmond.
But opponents of the path resurfacing plan claim it could damage wildlife habitats.
The Lake District National Park Authority (LDNPA) said it would make it more accessible for a range of users.
"This has got to be stopped," said Roy Smith, of Threlkeld, who launched the petition with his wife, Carol, in a bid to save the natural surface.
"It's going to destroy the whole basic environment you walk down."
The Friends of the Lake District group also opposes the resurfacing, warning it will "compromise" the rural feel of the route and could be slippy in icy conditions.
It also fears tree felling could impact on red squirrel habitats.
The LDNPA said the works, which will also include reinstating damaged bridges, would be carried out in a sympathetic manner and help prevent future long-term closures.
It said it had surveyed 2,500 people before announcing the plan and aimed to reopen the path next year.
"It's very clear people want to be able to walk and cycle safely and enjoy this fantastic environment," Mark Eccles from the LDNPA said.
"It also forms part of a national route between the coast in Cumbria and the coast in Yorkshire. It would be silly to miss the opportunity to improve this asset.
"We've got to remember this was an old railway line up until the 1970s carrying passengers, so it is a lovely environment but it is an industrial valley as well."