This study investigated changes in water temperature from 66 northern European cold-water springs during 1968-2012. The water temperature in most of these springs had increased by a statistically significant amount. Future estimates of the increase in water temperature in these springs due to climate change vary from 0.67 °C to 5.94 °C, depending on the climate scenario. High temperature increases are likely to change the ecology of these cold-water ecosystems, causing extinction of endemic specialist species and increases in the number of generalist species. It is possible that even just a small increase (of about 1°C) in water temperature in springs could cause extinction of endemic species and lead to regional-scale homogenization of ecosystems in northern European headwater streams.
Jyväsjärvi J, Marttila H, Rossi PM, Ala-Aho P, Olofsson B, Nisell J, Backman B, Ilmonen J, Virtanen R, Paasivirta L, Britschgi R, Kl ve B, Muotka T, 2015. Climate-induced warming imposes a threat to north European spring ecosystems. Global Change Biology 21, 4561-4569, doi: 10.1111/gcb.13067