New Harvard Forest Publication: Climate Change, Invasive Species & Northeastern Forests

Climate models predict that by 2100, the northeastern U.S. and eastern Canada will warm approximately 3-5°C, with increased winter precipitation. These changes will affect trees directly and indirectly through effects on "nuisance" species, such as insect pests, pathogens, and invasive plants. Harvard Forest Ecologist Dave Orwig and Population Ecologist Kristina Stinson recently joined a team of colleagues to review how basic ecological principles can be used to predict nuisance species' responses to climate change and how this is likely to impact northeastern forests. The team examined in detail the potential responses of two insect pest species [hemlock woolly adelgid (Adelges tsugae) and forest tent caterpillar (Malacosoma disstria)], two pathogens [armillaria root rot (Armillaria spp.) and beech bark disease (Cryptococcus fagisuga + Neonectria spp.)], and two invasive plant species [glossy buckthorn (Frangula alnus) and oriental bittersweet (Celastrus orbiculatus)]. Several of these species are likely to have stronger or more widespread effects on forest composition and structure under the projected climate. However, uncertainty pervades the predictions for many of these species because we lack adequate data on species ranges, tolerances, and life history, and because some species depend on complex, incompletely understood, unstable relationships. While target research will increase our confidence in making predictions, some uncertainty will always persist. Therefore, the team encourages policies that allow for this uncertainty by considering a wide range of possible scenarios.

Dukes, J.S., Et al., 2009. Responses of insect pests, pathogens, and invasive plant species to climate change in forests of northeastern North America: What can we predict? Canadian Journal of Forest Research. 39: 231-248.