A 32-year study of subarctic forest moths in Finnish Lapland suggests that scientists may be underestimating the impacts of climate change on animals and plants because much of the harm is hidden from view.
The study analyzed populations of 80 moth species and found that 90 percent of them were either stable or increasing throughout the study period, from 1978 to 2009. During that time, average annual temperatures at the study site rose 3.5 degrees Fahrenheit, and winter precipitation increased as well.
"You see it getting warmer, you see it getting wetter and you see that the moth populations are either staying the same or going up. So you might think, 'Great. The moths like this warmer, wetter climate.' But that's not what's happening,'' said ecologist Mark Hunter, the Henry A. Gleason Collegiate Professor in the U-M Department of Ecology and Evolutionary Biology.
Hunter used advanced statistical techniques to examine the roles of different ecological forces affecting the moth populations and found that warmer temperatures and increased precipitation reduced the rates of population growth.
"Yet, overall, most of these moth populations are either stable or increasing, so the only possibility is that something else other than climate change – some other factor that we did not measure – is buffering the moths from substantial population reductions and masking the negative effects of climate change."
The findings have implications that reach beyond moths in Lapland.
If unknown ecological forces are helping to counteract the harmful effects of climate change on these moths, it's conceivable that a similar masking of impacts is happening elsewhere. If that's the case, then scientists are likely underestimating the harmful effects of climate change on animals and plants, Hunter said.
Hunter and six Finnish colleagues report their findings in a paper scheduled for online publication April 15 in the journal Global Change Biology.
Listen to the podcast of Hunter's interview on Michigan Radio's Stateside.