Rare plants are vanishing from Scotland's mountains because of climate change, botanists warn.

Fragile Arctic species like the snow pearlwort are only found in a handful of places across the Highlands and Islands, where they thrive in chilly conditions.

A study by the National Trust for Scotland (NTS) has found many of these plants are now dying out as a result of Britain's warming climate.

A lack of low-lying snow, drier springs and milder, wetter winters are killing off plants at lower altitudes and forcing them to move higher up mountains, NTS experts say.

On Coire Nam Beith in Glen Coe, one population of Highland saxifrage has fallen from about 300 plants in the 1990s to around 30 in recent years.

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."

Lang Banks, director of environmental group 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."