Early Green, Early Brown – Climate Change Leads to Earlier Senescence in Alpine Plants

Typography

Global warming is leading to longer growing seasons worldwide, with many plants growing earlier in spring and continuing longer in autumn thanks to warmer temperatures—so the general opinion.

Global warming is leading to longer growing seasons worldwide, with many plants growing earlier in spring and continuing longer in autumn thanks to warmer temperatures—so the general opinion. Now, however, plant ecologists at the University of Basel have been able to show that this is not the case for the most common type of alpine grassland in the European Alps, where an earlier start leads to earlier aging and leaves the grassland brown for months.

Spring 2022 was extremely warm, giving many plants an early start to the growing season. And the Swiss Alps were no exception, with the snow cover melting early and the underlying vegetation being quickly roused into growth. Researchers at the Department of Environmental Sciences at the University of Basel have investigated how such an early start affects the plants’ further development.

For their study, they removed intact blocks of alpine grassland and placed them in walk-in climate chambers at Basel’s Botanical Institute. Here, they left the vegetation to overwinter artificially in cold darkness, and then switched some of the blocks to summer conditions in February. A second group was left in the cold dark until April, before summer was introduced here as well. The researchers compared the growth and aging of these plants with their neighbors growing naturally at an elevation of 2,500 meters, which did not emerge from the snow until late June.

Read more at: University of Basel

Alpine plants that start to grow earlier also start to age earlier. As is the case with the alpine vegetation in these containers, which were exposed to summer weather several months before the snow melted (photograph taken in July) (Photo Credit: Patrick Möhl, University of Basel)