Ayres Abstracts

Weed, A.S., M.P. Ayres, and J.A. Hicke. 2013. Consequences of climate change for biotic disturbances in North American forests. Ecological Monographs 83:441–470. Link. Reprint available on request. Coverage in New York Times, Science Daily, Washington Post, Dartmouth NOW, Ocala Star Banner, USDA Forest Service Southern Research Station. Aaron Weed interviewed on on WNYC's The Brian Lehrer Show (link).

Did the Polar Vortex freeze southern pine beetles out of the New Jersey Pinelands? NY Times. Analysis.

A story about a beetle. Outstanding related video by Milo Johnson (Dartmouth '13) about the biology and management of the southern pine beetle, with special reference to NJ Pinelands. Features interviews with Ron Billings, Texas Forest Service; Amy Karpati, Pinelands Preservation Alliance; and Kier Klepzig and John Nowak, Southern Research Station, USDA Forest Service.

Abstract from Ecological MonographsAbout one third of North America is forested. These forests are of incalculable value to human society in terms of harvested resources and ecosystem services and are sensitive to disturbance regimes. Epidemics of forest insects and diseases are the dominant sources of disturbance to North American forests. Here we review current understanding of climatic effects on the abundance of forest insects and diseases in North America, and of the ecological and socioeconomic impacts of biotic disturbances. We identify 27 insects (6 nonindigenous) and 22 diseases (9 nonindigenous) that are notable agents of disturbance in North American forests. The distribution and abundance of forest insects and pathogens respond rapidly to climatic variation due to their physiological sensitivity to temperature, high mobility, short generation times, and high reproductive potential. Additionally, climate affects tree defenses, tree tolerance, and community interactions involving enemies, competitors, and mutualists of insects and diseases. Recent research affirms the importance of milder winters, warmer growing seasons, and changes in moisture availability to the occurrence of biotic disturbances. Predictions from the first US National Climate Assessment of expansions in forest disturbances from climate change have been upheld – in some cases more rapidly and dramatically than expected. Clear examples are offered by recent epidemics of spruce beetles in Alaska, mountain pine beetle in high-elevation five-needle pine forests of the Rocky Mountains, and southern pine beetle in the New Jersey Pinelands. Pathogens are less studied with respect to climate but some are facilitated by warmer and wetter summer conditions. 
            Changes in biotic disturbances have broad consequences for forest ecosystems and the services they provide to society. Climatic effects on forest insect and disease outbreaks may foster further changes in climate by influencing the exchange of carbon, water, and energy between forests and the atmosphere. Climate-induced changes in forest productivity and disturbance create opportunities as well as vulnerabilities (e.g., increases in productivity in many areas, and probably decreases in disturbance risks in some areas). There is a critical need to better understand and predict the interactions among climate, forest productivity, forest disturbance, and the socioeconomic relations between forests and people.

Keywords: atmospheric drivers, greenhouses gases, outbreak, defoliators, pathogens, bark beetles, ecosystem interactions, economic impact, forest health management


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