May 15, 2017, by Tim Radford
Classic alpine flowers such as campanula are under threat as the world warms.
Image: Björn Groß via Flickr
Scientists warn that alpine flowers and plants could face extinction as warming forces them higher up into hostile rocky mountain terrain.
LONDON, 15 May, 2017 – Swiss, French and Austrian scientists warn that if the world continues to warm, alpine flowers will have nowhere to go but up. And since mountains tend to dwindle and get rockier with height, that leaves the plants nowhere much to go at all.
Long-lived species of alpine flowers could cling to life in their usual mountain pastures, but increasingly they may be unable to adapt to change.
And then, one day, some of the foliage that is the glory of alpine meadows – dianthus and campanula, primula and the evergreen grasses known as festuca or fescue − simply won’t be there at all.
It hasn’t happened yet. But conservationists who want to preserve the marvels of the mountains need to know how to tell when a species is in trouble.
Extinction risk estimates
To estimate the extinction risk to these plants, the scientists report in Nature Communications that they looked at a list of 24 species endemic to the Alps and selected four that could be found in 15 landscapes in the Austrian Alps, and that differed according to bedrock type, annual temperature and annual precipitation.
They then used computer models to see how these coped with global warming and associated climate change, as a consequence of the steady increase of greenhouse gases in the atmosphere, as a result of increased fossil fuel combustion.
Mountains everywhere are changing. Glaciers are melting, and some parts of the Alps in Europe are warming at twice the global rate.
Swiss ski resorts have been hit economically by shortages of snow, and researchers years ago observed that plants, birds and butterflies at home in the Alps are shifting their grounds and moving uphill as the mountains warm.
“If climate change continues to develop without
restraint, the plants will have a big problem”
Even highly-mobile and versatile mammals are responding. One team found that alpine chamois were dwindling in size as the thermometer rose.
So the mountain scientists modelled four long-lived endemic species of alpine flowers that endured in the spot to which they were rooted. They discovered that fewer and fewer young plants could get a foothold, and the implication is that population size could fall faster than the species’ available range contracts.
Disappearing alpine flowers
“The population numbers of these plants are dropping faster than the plants can adapt to the new conditions or spread to more favourable grounds,” warns Frédéric Guillaume, assistant professor in the department of evolutionary biology at the University of Zurich, who worked with colleagues from Grenoble and Vienna.
Their study suggests that alpine flowers and plants could not keep pace with fast climate change. Even species that are widespread could disappear quickly because they exist in small populations, separated by hostile terrain and conditions.
So conservationists need to take account not only of the way a species is dispersed, but also the local densities of population, to get a measure of the dangers of local and even global extinction.
Their models suggest that the alpine plants they studied could survive a global average warning of 1°C, and perhaps even recover if warming were to slow after 2090.
But that assumes that those nations who pledged, at the 2015 climate change conference in Paris, to work to contain global warming to less than 2°C will keep their word.
Dr Guillaume warns: “If climate change continues to develop without restraint, the plants will have a big problem.” – Climate News Network
Tim Radford, a founding editor of Climate News Network, worked for The Guardian for 32 years, for most of that time as science editor. He has been covering climate change since 1988.