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Lethal needle blight epidemic may be related to climate change

Increased summer precipitation apparently helping to spread spores of pathogen

American Institute of Biological Sciences

Biologists studying a lethal blight of lodgepole pines in northwestern British Columbia present strong evidence in the September issue of BioScience that climate change is to blame for the outbreak. The blight, caused by the fungus Dothistroma septosporum, causes trees to lose their needles and, in the case of the British Columbia outbreak, eventually die. D. septosporum has long been recognized as a pathogen of pines, but although it is considered a serious disease of exotic plantations in the Southern Hemisphere, it has until now been considered a minor threat to northern temperate forests. Lodgepole pines are an economically important species, being used in construction and for pulp.

Alex Woods and his colleagues at the British Columbia Forest Service and the University of Alberta investigated climate records in the area of the outbreak. The records provided no evidence of warming in the affected area in recent years, but they did reveal a clear increase in summer precipitation over the past decade. That constituted a smoking gun, because D. septosporum's life cycle depends on summer moisture for spore distribution. The increase in precipitation had no clear link to a known climatic oscillation that might have explained it, and the authors conclude that it is most likely related to a directional climate trend. The report of Woods et al. appears to represent one of a growing number of examples of an indirect effect of climate change, because increased summer precipitation would have been expected, absent D. septosporum, to benefit lodgepole pines.

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BioScience is the monthly journal of the American Institute of Biological Sciences (AIBS). BioScience publishes commentary and peer-reviewed articles covering a wide range of biological fields. The journal has been published since 1964. AIBS is an umbrella organization for professional scientific societies and organizations that are involved with biology. It represents some 90 member societies and organizations with a combined membership of about 240,000.

The complete list of research articles in the September issue of BioScience is as follows:

  • A Biosocial Approach for Analyzing Environmental Conflicts: A Case Study of Horseshoe Crab Allocation. Jay Odell, Martha E. Mather, Robert M. Muth.
  • Forecasting Regional to Global Plant Migration in Response to Climate Change. Ronald P. Neilson et al.
  • Is an Unprecedented Dothistroma Needle Blight Epidemic Related to Climate Change? Alex Woods, K. David Coates, Andreas Hamann.
  • Successfully Curating Smaller Herbaria and Natural History Collections in Academic Settings. Neil Snow.
  • The Origins of the Nile Perch in Lake Victoria. Robert M. Pringle.

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