The detention of Pema Tseden sparks fears over habitual violence by Chinese police against Tibetans.
He had evaded capture for three years after taking part in protests in Ngaba in 2008.
They are taken into custody without explanation a day after police assault other protesters, injuring eight.
They had resisted government orders to tear down 'illegal' shops and homes built near the lake.
Chuchen county residents fear mining may resume after briefly being stopped, though.
Only women take part in the march in hopes of avoiding attack by police.
He had founded an association dedicated to promoting education among Tibetan nomad youth, a Tibetan source says.
Their talks are held behind closed doors and away from the press to minimize offense to China, which objected to the meeting.
Chinese security forces watch the crowd but do not interfere, local sources say.
Chinese authorities try again to reduce the population of Serthar county's Larung Gar Buddhist Academy.
Lobsang Tsering was enrolled in restive Kirti monastery, the scene of frequent protests against Chinese rule.
Villagers oppose Chinese gold-mining operations on a nearby sacred mountain.
Property owners had applied for permission to build, but were turned down after failing to pay bribes, sources say.
The assault follows other raids last year against 'illegal' structures financed and built by nomads on their own land.
Freed three years ago after serving a 21-year term, he is seized by police at midnight in Tibet's capital Lhasa.
They are told not to block construction of a road planned to support mining operations in the area.
They are taken away by police with no word given on their present whereabouts or charges made against them.
Dangerous roads and exposed power lines lead to injuries and deaths, a local source says.
He has six years left to serve of a 13-year sentence for calling for the Dalai Lama's return to Tibet.
Police also found a call for Tibetan freedom written on the wall of his room, sources with contacts in the region say.
He is taken into custody while walking in prayer near his monastery, an exile source with local contacts says.
The practice of saving lives improves future rebirths for those taking part, Buddhists believe.
Chinese authorities change course after first telling Tibetan protesters they had no right to block the work.
Poetry writer and social commentator Jo Lobsang Jamyang is jailed for seven and a half years on unspecified charges.
More than 100 villagers have blocked traffic on a roadway, fearing more environmental damage from the mining activities.
A young monk is released after serving a two-year term, and a popular singer is freed after briefly being held for singing a banned song.
She calls out for Tibetan freedom and the Dalai Lama's return after setting herself ablaze outside a monastery.
He is taken away after displaying a photo of exiled spiritual leader the Dalai Lama and calling for Tibetan freedom.
They are taken into custody after trying to mediate in an argument between a Tibetan and a Chinese driver.
The move follows three decades of indiscriminate Chinese logging and ineffective government efforts at reforestation.