Europe's mountain summits are flush with new plant species, a greening that has increased in lock-step with the acceleration of global warming since the mid-20th century, researchers said on Wednesday. Looking at more than 300 summits scattered across the continent, they found that five times as many plant types migrated to higher ground over the last decade than did 50 years ago, from 1957 to 1966.
High mountain areas have warmed nearly twice as much as the planet as a whole, which has seen an increase of one degree Celsius (1.8 degrees Fahrenheit) since the mid-19th century. "Across all summits, the increase in plant species richness has accelerated," a team of 53 scientists led by Sonja Wipf from the Institute for Snow and Avalanche Research in Davos, Switzerland reported in the journal Nature.
"This acceleration has been particularly pronounced during the past 20-30 years." But the flourishing of high-altitude flora may be ephemeral, the researchers cautioned.
"Even if biodiversity is increasing, it's not something that will necessarily persist," said co-author Jonathan Lenoir, an expert in biostatistics at France's National Centre for Scientific Research. "We may be seeing the accumulation of an extinction debt if these new arrivals crowd out the emblematic, and more fragile, high-altitude species," he told AFP.
In ecology, "extinction debt" refers to the delayed negative impact on a species of changes in the environment, such as habitat loss or decreased rainfall.