Tracking the movement of plants

The vegetation of the Alps is undergoing significant shifts due to climate change. Botanists from the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) Institute for Snow and Avalanche Research SLF are studying how these changes are impacting plant diversity in Graubünden, Switzerland. They are comparing current data with records from nearly a century ago to track the movement of plant species.

Christian Rixen, a botanist and co-leader of the Flora Raetica project, has observed that certain plants have either reappeared or disappeared in the region. For instance, mat-grass and alpine vernal grass, which both have pleasant scents, are being recorded again after a lapse of years. However, other species like the mountain buttercup and alpine sedge, which were previously found in the area, are now absent.

Rixen has even discovered a spruce tree and three larches growing at elevations higher than usual, a phenomenon attributed to rising temperatures.

The Flora Raetica project involves 1,104 survey plots, each spanning 100 by 100 meters, where researchers document the plant species present. The data collected is then compared with historical records from the 1930s to identify trends in elevation ranges and species distributions. While some plants are benefiting from the warmer climate, many require a specific amount of accumulated warmth throughout the year, and thus, are experiencing altered life cycles with earlier autumns.

Citizen scientists play a crucial role in this project, contributing to the effort by using a smartphone app to log observations. The project not only focuses on surveying but also welcomes other forms of citizen science participation, such as identifying rare species or Red List species. This collaborative approach aims to understand how warming temperatures are reshaping alpine flora across Graubünden.