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.

Redbay (Persea borbonia L. Spreng) Seedling and Sapling Growth and Recruitment Near Trees with and without Putative Resistance to Laurel Wilt Disease

“…For over a century, anthropogenic activities have facilitated the biological invasions of exotic pests and pathogens into new habitats throughout the world [1][2][3][4][5][6]. In North…”

“…For over a century, anthropogenic activities have facilitated the biological invasions of exotic pests and pathogens into new habitats throughout the world [1][2][3][4][5][6]. In North America, introduced pathogens have caused significant population declines in numerous tree species [2,[5][6][7][8][9][10].…”

“…For over a century, anthropogenic activities have facilitated the biological invasions of exotic pests and pathogens into new habitats throughout the world [1][2][3][4][5][6]. In North America, introduced pathogens have caused significant population declines in numerous tree species [2,[5][6][7][8][9][10]. Laurel wilt is a vascular wilt disease that has plagued various North American members of the Lauraceae dating back to the 2002 introduction of the Asian redbay ambrosia beetle [Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae)] into the southeastern United States [11][12][13][14][15].…”

From a cause of rapid fig tree dieback to a new threat to mango production: the invasive bark beetle Cryphalus dilutus Eichhoff (Coleoptera: Curculionidae, Scolytinae) and its associated fungi found on mango trees in Europe

“…Some species are also known for the massive economic and ecological damage that they can cause during outbreaks in their native range and especially after introduction in new areas. The number of invasion events caused by bark beetles and associated microorganisms in new environments has increased rapidly in recent decades (Biedermann et al., 2019; Faccoli et al., 2020; Li et al., 2022; Marincowitz et al., 2020; Schebeck et al., 2023; Tanin et al., 2021) as a consequence of climate change and the intensification of international trade (Lantschner et al., 2020; Loehle et al., 2023; Vilardo et al., 2022; Ward et al., 2023), reaching alarming levels. The situation may be even more serious than currently known due to ongoing cryptic invasions (Mas et al., 2023; Morais & Reichard, 2018).…”