Moth Study shows Climate Change Effects Masked
While populations of 80 moth species in Finnish Lapland are generally either stable or increasing, a study by the University of Michigan suggests their growth rates have been dropping, according to a release from the school. The researchers concluded from the 32-year study that the impact of climate change on animals and plants is being underestimated because much of the harm is hidden from view.
"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," said University of Michigan ecologist Mark Hunter. "So you might think, 'Great. The moths like this warmer, wetter climate.' But, that's not what's happening."
In his analysis, Hunter looked at the different ecological forces that affect moth populations and found that warmer temperatures and increased precipitation reduced the rates of population growth.
"Every time the weather was particularly warm or particularly wet, it had a negative impact on the rates at which the populations grew," said Hunter. "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."
Most recent studies on moth populations have shown steep declines. So Hunter and his colleagues were surprised to find that 90 percent of the moth species in the Lapland study were either stable or increasing.
"The big unknown is how long this buffering effect will last," Hunter said. "Will it keep going indefinitely, or will the negative effects of climate change eventually just override these buffers, causing the moth populations to collapse?"
Scientists are able to derive key insights from insects and how climate change affects them because of their wide range of roles as agricultural pests, pollinators, food sources, carriers of disease, and drivers of different ecosystem processes.
If unknown ecological forces are helping to mask the harmful effects of climate change on these moths, it is possible that a similar effect is taking place elsewhere. As a result, scientists are likely underestimating the harmful effects of climate change on animals and plants, Hunter said.
"We could be underestimating the number of species for which climate change has negative impacts because those effects are masked by other forces," he said.
Hunter and his Finnish colleagues published their findings in the journal Global Change Biology.