Climate change puts great pressure for change on species and biodiversity. A recent study by the University of Helsinki and the Finnish Environmental Institute indicates that the few species of moths and butterflies (Lepidoptera) capable of adapting to climate change by advancing their flight period and moving further north had the best results in Finland. In contrast, around 40% of Lepidoptera species have not been able to respond in one way or another, seeing their populations decline.
Climate change is causing rapid change in Finnish nature – can species keep pace? Adaptation to climate change may manifest as earlier phenology, such as periods of flight of moths and butterflies, nesting birds, or flowering of plants earlier than before. Species can also adapt by moving their range further north, as individuals move to new areas where conditions have become favorable.
The researchers stress that, in order to preserve biodiversity as climate change intensifies, it is of the utmost importance to ensure sufficiently large, interconnected and quality habitats that allow species to adapt to the challenges generated by climate change. .
The study conducted by the University of Helsinki and the Finnish Environmental Institute compared the temporal changes in the flight period of 289 moths and butterflies and the spatial changes in their northern range limit, as well as changes in abundance over a period of about 20 years.
“About 45% of the species we studied had moved north or had advanced their flight period,” says postdoctoral researcher Maria Hällfors from the University of Helsinki. “They did a lot better than the 40% of species that didn’t respond in one way or another. On average, populations of these poorly responsive species had declined. north and advanced their flight. This demonstrates that the ability to respond to a changing environment is vital for species.
Few species have advanced their phenology
Another interesting finding was the fact that while almost half of the species had moved north, only 27% had advanced their flight period.
“This finding deviates from observations made elsewhere in Europe where the advance of the flight period was much more frequent in Lepidoptera”, explains principal researcher Juha Pöyry of the Finnish Institute for the Environment.
In Finland, the species that have advanced their flight the most are those that overwinter in adulthood, including the European peacock. In fact, it seems that Lepidoptera species living in Finland react more easily by expanding their ranges northward rather than by advancing their flight. Species that are found further north than before include the wood moth and rare copper.
“It may be that the increased light in the spring is a more important signal for butterflies and moths to begin their flight than the temperature alone,” adds Pöyry.
Sufficient habitat is essential
One potential explanation for the scarcity of optimally responding species, i.e. both advancing their flight and moving north, could be the scarcity of suitable habitats.
“For organisms to respond to climate change by moving their range further north, sufficient amounts of suitable high-quality habitat are needed,” says Mikko Kuussaari, senior researcher at the Finnish Environment Institute.
The amount of important habitat for many species of moths and butterflies has declined, leading to population declines for many. For example, many species of butterflies have suffered from a decrease in grasslands.
“Declining populations are usually not able to provide a sufficient basis for the species to spread to new areas. Small populations also contain less genetic diversity which could help local populations adapt by changing the pattern. moment of their flight, “adds Kuussaari. In fact, safeguarding biodiversity requires above all the maintenance of sufficiently large and interconnected habitats of quality.
Long-term follow-up allows research
The study used data on Lepidoptera flight times collected as part of two long-term monitoring projects coordinated by the Finnish Environment Institute. Among the two, the Finnish National Moth Monitoring Program was launched in 1993 and the Butterfly Monitoring Program in Agricultural Landscapes in 1999. A dataset of citizen sightings freely available through the Finnish Information System on biodiversity was used to calculate shifts in the range boundaries of species.
“Without such long-term monitoring programs and the great contribution of butterfly and moth enthusiasts in collecting observations, as well as collaboration between different research organizations, it would be impossible to carry out this type of research. ‘analyzes encompassing hundreds of species,’ says Associate Professor Marjo Saastamoinen of the University of Helsinki.