A new study by Los Alamos National Laboratory scientists and colleagues confirms that increasing minimum winter temperatures allow beetles to expand their range but reveals that overcrowding can put the brakes on population growth.
“It has long been predicted that warming winters will allow range expansion. This is the first large dataset that demonstrates that warmer winter temperatures are likely allowing mountain pine beetles to establish outside of their native range,” said Devin Goodsman, a Los Alamos postdoctoral researcher and first author on the report. “Both competition and winter cold are known to be important causes of mortality, but no previous studies addressed how these mortality factors interact.”
Although the insect is diminutive, the bark beetle’s impact is colossal. Massive outbreaks in recent decades have consumed large swaths of Western forests, where 100,000 trees may fall every day. Some regions have lost 90 percent of the conifers. The outbreaks, mounting in size and severity, are now infesting new tree species and expanding beyond the Continental Divide across North America and into boreal forests.
Read more at DOE/Los Alamos National Laboratory
Image: North American bark beetle outbreaks have killed millions of trees. A new study demonstrates how the Mountain Pine Beetle's range is expanding due to warming temperatures but reveals how overpopulation might decelerate growth. (Credit: LANL)