* Environmentalist loses appeal against sentence
* Rights activists says case politically motived
* Putin stakes prestige on Sochi Games
By Ian Bateson
MOSCOW, Feb 12 (Reuters) - A Russian environmentalist who campaigned against ecological damage from construction work for the Sochi Olympics is to spend three years in a prison colony, after losing an appeal against his sentence on Wednesday.
Supporters said Yevgeny Vitishko, who was convicted of damaging the regional governor's property, was being punished for publicising problems caused by the Winter Games.
"The case against Vitishko has been politically motivated from the start," Yulia Gorbunova, Russia researcher at New York-based Human Rights Watch said in a statement.
"When the authorities continued to harass him it became clear they were trying to silence and exact retribution against certain persistent critics of the preparations for the Olympics."
Vitishko initially received a suspended sentence in 2012 for "deliberate destruction of property" after spray-painting the word "thief" on the fence of the residence of the pro-Kremlin governor of Krasnodar region, Alexander Tkachyov.
Vitishko has denied the charges and said the governor's residence was in a national forest where construction was not supposed to be permitted.
His prison sentence was reinstated last year after he was accused of violating the terms of his suspended sentence by ignoring restrictions on travel outside his hometown of Tuapse, near Sochi, on the Black Sea.
That decision was upheld on Wednesday by a court in Krasnodar, 170 km (100 miles) northwest of Sochi.
Another environmental campaigner, Suren Gazaryan, fled to Estonia and received political asylum after also being handed a suspended sentence in 2012 over the protest at the governor's residence.
PUTIN'S PET PROJECT
Their treatment is widely seen by human rights groups as an attempt to stifle criticism because President Vladimir Putin has staked so much personal and political prestige on the Games.
"Yevgeny refused to leave and now he has paid the price," said Dmitry Shevchenko, deputy coordinator of Environmental Watch on the North Caucasus, the group Vitishko belongs to.
The Kremlin denies using the courts for political purposes and says there are no political prisoners in Russia.
Environmental Watch on the North Caucasus challenges this. It drew up a report this month on environmental damage caused by the Games preparations and has led protests.
The group said Vitishko was detained last week after being accused by police of swearing in public, ensuring he would be unable to travel to Sochi for the Olympics or the arrival of the Olympic torch relay.
"Locking up Vitishko and other Environmental Watch activists on the eve of the torch relay was no coincidence," Gorbunova said.
"It is hard to avoid concluding that local authorities were trying to get this outspoken critic out of the way in the final lead-up to the games and also to silence him as his appeal neared." (Reporting by Ian Bateson; Editing by Timothy Heritage and Andrew Roche)