Prolonged heatwaves threaten species adaptation in Finland, study reveals

Prolonged heatwaves pose a significant challenge for many species, according to new research from the University of Jyväskylä. Doctoral researcher Emmi Räsänen examined the differences in organisms’ abilities to adapt to stable and varying temperatures. Her study focused on fungal and bacterial species, which can be rapidly cultivated under climate change-relevant conditions.

Climate change is also reducing the populations of many species, exacerbating the situation as individual numbers increase. Räsänen’s research revealed that smaller populations adapt to heat much more slowly than larger ones. Increased temperature variability poses a serious threat, particularly to ectothermic species, which comprise the majority of Earth’s organisms. These species’ body temperatures align with their environment.

“The past two years have been the hottest on record, which is evident in the duration of heatwaves in Finland,” Räsänen stated.

Some ectothermic organisms can evade extreme temperatures by entering a state of dormancy. However, even a one-degree Celsius increase can be critical for an organism if it exceeds its tolerance threshold. Studying heat tolerance is challenging, which is why Räsänen measured the growth and reproductive rates of the organisms as an indicator of their adaptation to varying conditions.

Interestingly, Räsänen found that mainly the same genes regulate organisms’ adaptations to both stable and fluctuating temperatures. “Notably, some genes influencing adaptations are specifically affected by certain temperatures or variations,” she noted.

Emmi Räsänen’s doctoral research will be examined on Friday, September 13.