Climate change is transforming moth communities across Finland. According to researchers at the University of Helsinki, cold-adapted species are disappearing in the North while Southern Finland is seeing an influx of warm-adapted species from mainland Europe.
A new study led by the University of Helsinki examined how climate change is altering moth communities across Finland. The researchers wanted to understand whether communities are undergoing thermophilisation - a shift towards species that prefer warmer conditions - as the climate warms.
The team drew on a long-term dataset built through decades of dedicated volunteer monitoring. It includes more than 224,000 moth observations collected across Finland's 1,200 km length over two 30-year periods. This extraordinary effort made it possible to uncover how climate change is reshaping moth community composition across the country.
Their findings confirm that Finnish moth communities are becoming increasingly dominated by warm-adapted species. While the community warming was consistent across the country, the mechanisms that lead to it were strikingly different.
In Northern Finland, thermophilisation was primarily driven by the disappearance of cold-adapted species. In contrast, Southern Finland experienced thermophilisation through the arrival of new warm-adapted species, while most resident species persisted.
These findings suggest that cold-adapted species in Northern Finland are particularly vulnerable under climate change, as the communities face more species losses than additions. This pattern points to a greater risk for communities at the cold edge of species' climatic ranges.
"The rate of change in the composition of moth communities was twice as fast in the North compared to the South," says lead author Dr. Emilie Ellis from the Research Centre for Ecological Change. "That rapid pace makes northern biodiversity especially vulnerable to the harmful effects of climate warming"
Recognising that cold-adapted species are at risk will help to inform conservation strategies to support Finnish biodiversity. Continued monitoring and research are therefore crucial to track how these species are changing over time.
The research was done in collaboration with the Finnish Environment Institute.
