Monitoring for the National Trust for Scotland (NTS) has revealed that many fragile alpine species are vanishing from areas they used to inhabit and retreating to higher altitudes as a response to global warming.
Conservationists say milder, wetter winters, drier springs and a decrease in lying snow are all having an impact on the plants growing on Scottish peaks.
Studies of species at some of the nation’s best-loved beauty spots have revealed serious declines.
In some cases, plants have completely vanished from lower level locations where they had previously thrived.
Experts have been analysing survey results stretching back to the 1950s, which show the impact of rising temperatures.
NTS ecologist Dan Watson said: “Our monitoring shows that climate change is affecting Scotland’s mountains at an alarming rate.
“Trust monitoring tracks the decrease of rare arctic-alpine plants such as snow pearlwort on Ben Lawers and Highland saxifrage in Glencoe and shows how populations are declining at lower altitudes.
“Meanwhile, common temperate plants less able to cope with extreme climates are moving further up the hills.”
Environmental campaigners say the results are “worrying” and reinforce the need for strong measures to reduce greenhouse gas emissions.
Lang Banks, director of WWF Scotland, said: “These important studies reveal the worrying fact that, as a result of climate change, many of Scotland’s cold-loving plant species are literally running out of mountain.
“It’s therefore vital that all our elected politicians are made aware of these finding and continue to support action to address climate change.
“With the Scottish Government putting together a new climate change action plan for the end of the year, this is a reminder that a bold actions are needed to protect wildlife and secure the full benefits of moving to a zero-carbon economy.”
Mr Watson says the findings highlight the need for further research to be carried out before it is too late.
“As the distribution of plants found at high altitude is changing, more work is required to confirm the extent of the problem,” he added.
“These results are firm evidence of the rise in mountain temperatures and the decrease in lying snow on southerly slopes and at lower altitudes.
“Current estimates indicate that snow cover at 1,060m is projected to be reduced by 21 per cent by the 2050s.”
The NTS currently undertakes detailed research on a six-year cycle, which is producing evidence of a long-term trend towards extinction, particularly on lower-lying, south-facing slopes.
On Coire nam Beith in Glencoe, one population of Highland saxifrage has fallen to just a tenth of its former size over the past 25 years - from 300 plants in the 1990s to only 31 today.