Preventing the Perfect Storm of Forest Mortality in the United States Caused by Invasive Species

Abstract

Invasive species are a growing global threat to forest ecosystems. In North America, previous invasions have functionally eliminated the American chestnut (Castanea dentata), a keystone and commercially important species in eastern North American forests, and currently threaten to eliminate other important species, such as ash (Fraxinus spp.), redbay (Persea borbonia), and eastern hemlock (Tsuga canadensis). Invasive species, particularly invasive insects, pathogens, and plants, threaten forest ecosystem integrity and put commercial forestry at risk. However, as the threat from invasive species grows due to expanding international trade, the scientific workforce with specialized expertise and training to mitigate current threats and, more importantly, avoid future threats, has been declining over the past 40 years. Research funding and administrative capacity to respond have also not kept pace with increased frequency and risk of species introductions. Herein, we review the nature of this ongoing challenge by examining contributing factors, including documenting trends in expertise and funding. In addition, we make recommendations for resources needed and information gaps that should be addressed and justify the need for increased support for basic biological research and further exploration of techniques to identify and treat potential threats (e.g., sentinel studies). Study Implications: The US faces an invasive species crisis. Major tree species are already being decimated. The forest products industry relies primarily on a hand full of species. A new insect or disease could thus decimate the industry. We show that the pace of introductions has accelerated due to greater and faster shipping volume. Port screening and sanitation need considerable improvement, especially for live plants, which harbor insects and pathogens. Interior monitoring and overseas sentinal studies need enhancement for better detection of threats. More research and control staff are needed at government and university posts, especially to enable rapid response. Finally, research is needed on new detection and control technologies.