Crews remain at the incident Langdale Moor near RAF Fylingdales which started on Monday, August 11.
At its height, 20 pumps were at the scene and a helicopter was used to try to control the blaze, as the fire service declared it a major incident.
Elspeth Ingleby, from the North York Moors National Park Authority (NYMNPA), said the area affected covers a site of special scientific interest, a special conservation area and a special protection area.
She said: “It’s catastrophic for the habitats that are found in that location and the wildlife that currently lives there.
“The animals most impacted are those that cannot move quickly enough to escape the fire or cannot burrow below the extent of the fire. With that in mind, bird nests, during the breeding season, are definitely vulnerable along with adders, lizards, frogs and toads and small mammals.
“For significant wildfires a depth of soil or peat will also get intensely hot so any animals with burrowing instinct are also likely to have perished unfortunately.”
Elspeth said populations of common animal species will gradually re-colonise the site over time as the vegetation and habitats re-establish but this could take years.
” For species that depend on bog habitat, it may take even longer due to the time taken to re-establish the wet peat forming conditions that they require. As an example, an area of long heather that was being managed on Fylingdales Moor for merlin breeding has been destroyed in the Langdale fire.
“Merlin are the UK’s smallest bird of prey and usually nests on the ground on heather moorlands. The nest requires sufficient cover for the adults and chicks to hide so need heather at least 10 years old. Merlin have declined nationally, so losing a potential breeding site is a huge loss. The area will take well over a decade for sufficient depth and height of heather to re-establish before the site could be used for breeding merlin again.”
Elspeth said peat is very slow to accumulate with an average rate of only 1mm per year.
“The wildfire could be undoing thousands of years of peat and carbon storage, with heritage and history below the surface lost, well as habitats above the ground.
“It can take many decades, centuries and even thousands of years to really recover from that kind of impact.”
Crews from a number of stations including Malton, York, Helmsley and Easingwold have been battling the blaze.
Over the weekend smoke from the fire, at Langdale Moor, could be smelt as far away as York and Tadcaster.
A spokesperson for Malton station said: “It’s been a long old week for crews at Malton, spending the majority of the time on Langdale Moor. Especially Blue watch, who had worked extremely hard from the start of their tour on Tuesday through till their last day on shift, on Friday.
“The fire on Langdale Moor has nearly been extinguished, but only due to the team work and dedication from all the fire stations, farmers and land owners, that have attended this incident since it started on Monday night.”
Chief Fire Officer Jonathan Dyson has thanked people for the support they’ve offered this week while crews have been dealing with the fire.
He said: “Our crews, control room staff and officers, have worked around the clock this past week to tackle the moorland fire at Langdale. It’s been especially hot and tiring work for the crews and officers at the scene.
“The generosity of communities and businesses through donations, support and well wishes has been truly outstanding. I’m especially grateful to local farmers, gamekeepers and partner agencies who’ve assisted on the ground and to our neighbouring fire services for providing additional resources.”
The service is today urging people not to go to Langdale Moor and Langdale Forest where crews are still working following reports of people visiting the area to take photos of the devastation.
The rest of the North York Moors National Park and Dalby Forest remain open, said a spokesman.
On Friday morning, the NYMNP asked members of the public to “consider their actions” because of the “extreme fire risk”.
In a statement, it said ground vegetation and forests were “tinder-dry, creating the perfect conditions to spread rapidly and out of control”.
Visitors to the area were urged not to discard cigarettes or matches, light fires or barbecues, or leave glass bottles or reflective litter, to help “prevent catastrophe”.
