Motorcyclists who use part of a Cornish moor are being targeted in a joint initiative involving the police, Cornwall Council and Natural England.
The idea behind the purge is to stop bikers using the Goss Moor trails.
The move follows a number of incidents where motorcyclists have forced family groups of cyclists off the trail and frightened horses and their riders.
Police are patrolling the area and signs have been erected informing bikers they could be breaking the law.
The signs, from Cornwall Council, are sited at all main access points where motorbikes are known to enter the moor.
Anyone found in breach of the law could receive a fixed penalty fine or have their bike seized by the police.
Julian German, Cornwall Council cabinet member for the environment, said: "The Goss Moor trails are set into a wonderful backdrop of mining and land management history and has been awarded Site of Special Scientific Interest status.
"Unfortunately, a by product of creating these trails has been the illegal use of motorbikes which have become dangerous and unpleasant for legitimate users."
Martin Davey, Natural England's Senior Reserve Manager for Goss Moor National Nature Reserve, added: "Since opening in May 2008, the trail through Goss Moor has become a very popular community resource for local people.
"The purpose of this seven mile circular trail is for quiet public enjoyment in a peaceful natural setting.
"People should not have to worry about disturbance or verbal abuse from motorcyclists who shouldn't be there in the first place."