The study, which spans several decades, found that vegetation changed in many areas in terms of vegetation type, species richness and plant growth between 1981 and 2022. The study covered more than 2,000 plant communities in 45 areas across the Arctic tundra.

Shrubs and grasses increased, while flowering plants declined as they struggled to survive under the shade of taller plants.

The study provides insight into how climate change is shaping the Arctic tundra, which is warming four times faster than the global average. The changes in vegetation identified by the study are an early warning sign that entire ecosystems may be changing. The change affects animals, people and the planet's carbon stocks.

The study was led by the University of Edinburgh in collaboration with the University of British Columbia and 49 partner institutions. From Finland, researchers from the Natural Resources Institute Finland and the Universities of Helsinki, Eastern Finland and Lapland participated. A team of 54 researchers analysed more than 42,000 field observations from 2,174 plots and compiled a database of plant species diversity. The observations were collected from the high Arctic region in Canada and Svalbard, and from areas above the tree line in Alaska, Canada and Fennoscandia.

Temperature and competition between plants as drivers of change

According to the results, the main drivers of changes in plant species diversity are rising temperatures and competition between plants.

– When we think of the Arctic, we usually imagine a barren and desolate ecosystem. However, Arctic nature is surprisingly diverse, and up to dozens of plant species can live on the tundra per square meter, says lead author Mariana García Criado, a postdoctoral researcher at the University of Edinburgh.

– Rising temperatures bring more species, but not everywhere. Shrubs often shape Arctic ecosystems in a way that reduces biodiversity, but this is not always the case. It was surprising to see how the composition of plant communities changed in many different ways, Criado continues.

It is often thought that biodiversity is decreasing as a result of climate change. However, in temperature-limited tundra areas, the effects of climate change are more diverse.

– In some of our study areas, biodiversity increased with warming, but where shrubs took over, it decreased. So our study shows that biodiversity can follow many different paths in a rapidly warming Arctic environment, says Professor Isla Myers-Smith from the University of Edinburgh and the University of British Columbia.

Long-term observations and research cooperation enable new findings

The information generated by the study is crucial for understanding changes in the coldest ecosystems on Earth.

– Long-term observations from several areas revealed that although the total number of plant species in the tundra did not change as a result of warming, both the appearance and disappearance of species were more common in areas that warmed the most, says Academy Research Fellow Elina Kaarlejärvi from the University of Helsinki.

– International long-term cooperation in compiling comprehensive data brings strong predictive power to the study, says Professor Anne Tolvanen from the Natural Resources Institute Finland.

– The experimental area established in 1994 in subarctic Kilpisjärvi represents Finland in this study. It is one of the longest-running field projects of this research group,” Tolvanen continues.

– While focused mainly on vascular plants, the study acknowledges that non-vascular species (e.g. bryophytes, lichens) play an increasingly important role in tundra biodiversity, says Research Professor Bruce Forbes from the Arctic Centre, University of Lapland. He draws on 40 years of experience observing long-term vegetation changes in Arctic Eurasia and North America.

For more information:

UK/Europe: Rhona Crawford, Press and PR Office, University of Edinburgh. rhona.crawford@ed.ac.uk 

Finland: Anne Tolvanen, Professor, Natural Resources Institute Finland, anne.tolvanen@luke.fi

Arctic Centre at the University of Lapland, Research Professor Bruce Forbes, +358 40 847 9202, bruce.forbes@ulapland.fi 

Read more from Nature article: Plant diversity dynamics across space and time in a warming Arctic