Dry heat increases bark beetle bite

May 02, 2012

Climate change appears to be good news for destructive bark beetles, according to a new study by Lorenzo Marini from the University of Padova in Italy, and his team. Their work, published online in Springer's Climatic Change, shows that there were more attacks by the spruce bark beetle on European Alpine spruce forests over a 16 year period, as temperatures rose and rainfall dropped.

Shifts in temperature, rainfall, and atmospheric gas concentrations, as well as destructive activities by pests and pathogens, are having a profound effect on forest ecosystems. The spruce bark beetle Ips typographys (L.) in particular, is one of the most destructive pests of the European forests, and it is expected to quickly respond to . Forest damage due to this bark beetle has increased markedly during the last decades throughout the whole of Europe.

The researchers analyzed the pattern and impact of outbreaks by the bark beetle, by assessing the extent of timber loss in a mountain region on the southern border of the European Alps. They described the size and distribution of the infested areas occurring along steep temperature gradients over a 16-year period (1994-2009), as well as climatic variations.

Two types of forests were identified: so-called 'on-site' forests where Norway spruce is within its limits of historical climate range, at higher altitudes where temperatures are generally cooler; and 'off-site' forests where spruce is growing outside of its natural climatic range, at lower altitudes and in a warmer climate.

Both the extent and location of timber loss were linked to . Dry summers combined with warm temperatures were significant triggers for severe outbreaks. Forest damage per hectare was on average 7-fold higher where spruce was planted in sites warmer than those within its historical climate range (off-site). Although trees planted off-site grew substantially faster, their defences against the bark beetle were probably weakened by both low rainfall and warmer temperatures. In addition, dry conditions in the previous year encouraged the bark beetle to move to higher altitudes. The low rainfall at those higher altitudes gave the beetles new opportunities to find suitable, weaker host trees which, under normal rainfall conditions, would have been less susceptible to bark beetle attacks.

The authors conclude: "Considering the increased susceptibility of spruce forests to bark beetle outbreaks, the most reliable and ecologically sound strategy to reduce outbreaks of I. typographus is sustainable forest management, including avoiding planting spruce outside its natural climatic range."

Explore further: Scientist discovers populations of rare songbird in surprising new habitat

More information: Climatic Change DOI 10.1007/s10584-012-0463-z

Related Stories

Complex dynamics underlie bark beetle eruptions

Jun 02, 2008

Forest management that favors single tree species and climate change are just two of the critical factors making forests throughout western North America more susceptible to infestation by bark beetles, according to an article ...

Global warming seen in Alaska's greening

May 30, 2006

A forest ecologist in Alaska is warning that the state is losing its forests to global warming and could soon turn out to be a state of grasslands.

Recommended for you

Nestling birds struggle in noisy environments

Oct 29, 2014

Unable to fly, nestling birds depend on their parents for both food and protection: vocal communication between parents and offspring helps young birds to determine when they should beg for food and when they should crouch ...

The secret life of the sea trout

Oct 29, 2014

Jan G. Davidsen and his graduate students are spies. They use listening stations and special tags they attach to their subjects to track their movements. They follow their subjects winter and summer, day ...

Giant tortoises gain a foothold on a Galapagos Island

Oct 28, 2014

A population of endangered giant tortoises, which once dwindled to just over a dozen, has recovered on the Galapagos island of Española, a finding described as "a true story of success and hope in conservation" ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.