Only half-a-degree temperature increase affects aquatic invertebrate communities

Torstai 14.2.2019 klo 15:38 - Mikko Nikinmaa

When the threats caused by climate change are discussed, it is often brought forward that temperature increase above 1.5 degrees would be critical. Usually verified data of what has already happened is not brought forward. Another proSci_Total_Environ.jpgblem with most biological climate change studies is that conclusions are based on experiments lasting days or weeks instead of the many years that are required for the temperature increase in nature that is rapidly achieved experimentally. A recent study in the Science of the Total Environment avoided both problems. Haase et al. (Sci. Total Environ. 658, 1531-1538; 2019) have followed the invertebrate communities in some Central European streams for 25 years. During that time the temperature has increased only 0.5 degrees. However, despite the minute temperature change, the invertebrate communities were markedly affected. At first sight, as compared to the recently reported decrease of insect diversity, the findings look good: both the total abundance and the diversity of invertebrates increased by approximately 40 %. However, when the groups were differentiated on the basis of their temperature preferences, it was observed that the abundance and diversity of cold-water taxa was halved. For the species living in the north this is very bad news. Temperature changes occurring already, and not ones expected to occur 30 years from now, may cause their extinctions.

So, political decision-makers should start taking the school-children demonstrating for climate actions instead of going to school seriously, not just saying that we are taking climate issues into account in our decisions, as long as they affect economic growth minimally.

Kommentoi kirjoitusta. Avainsanat: climate change, community ecology, freshwater biology