Climate change has been affecting plants over the last century and caused
changes in life history features such as the flowering time. Herbarium specimens provide
a snapshot of the past environmental conditions during their collection. The collection
date in a herbarium specimen is a good proxy to determine the flowering period (phenology).
In this study, phenological data from subarctic plant specimens collected over
100 years were gathered by using one of the largest herbarium databases in the World.
The collection dates of 7146 herbarium specimens were analyzed and significant shifts
in the phenology of subarctic plants were detected. In this study, most of the analyzed
142 species in a subarctic biogeographic region tended to flower earlier in the 1950–2018
period compared to the 1900–1949 as a possible result of the climate change. Flowering
time shifted from 8 to 26 days in some species. Changes in flowering time may
alter species interactions, community composition, and species distribution in a region.
Therefore, results of this study may shed light on the possible shifts in phenology and
plant responses under the climate change.