FORESTRY England has closed nine New Forest car parks and placed restrictions on walkers in a bid to protect rare ground-nesting birds.
The organisation, which is taking part in a UK campaign to ensure the survival of species such as lapwing, nightjar and curlew, says the car parks will remain shut until late summer.
The closures aim to create special quiet zones in breeding locations across the district.
Forestry England bosses hope their attempt to limit activity will reduce the likelihood of birds abandoning nests and thus exposing their chicks to predators.
The New Forest is a Special Protection Area for Birds and a critical breeding location for endangered ground-nesting species.
People entering the quiet zones should stay on the main tracks and avoid areas of open heathland where birds may be nesting.
Orange signs indicate areas near breeding grounds. Red 'stop' signs highlight the presence of nesting sites in the immediate vicinity and urge people to take another route.
People walking their dogs are being urged to keep them on the lead "if necessary" to ensure they remain under close control.
Forestry England ecologist Leanne Sargeant said: "Anyone who has heard or seen ground-nesting birds on the Forest will know how incredibly fortunate we are to be visited by them.
"We are asking the public to help us make sure this doesn’t happen in the New Forest by making some really simple changes."
Heather Gould, head of the New Forest Dog Owners' Group, said: "The New Forest is a really special place for birds.
"It’s really simple for everyone who spends time here to help protect them by obeying the signs which are put out. Even better, please avoid any sensitive area altogether."
Horse riders are also being urged to stick to the main tracks.
Richard Taylor, chairman of the New Forest Cycle Working Group, said: "The New Forest is a haven for wildlife, making it a magical place to cycle and tune into the sounds of different types of bird song.
"To keep this place special it’s vitally important to cycle on the way-marked cycle routes, especially during the ground-nesting season. When planning your route, know where the quiet zones are located and which car parks are closed."
The car parks involved are: Clayhill, Crockford, Crockford Clump, Hincheslea, Hincheslea Moor, Ocknell Pond, Ogdens, Shatterford, and Yew Tree Heath.
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