Chapter 8: Invasive plants
| Authors: | Andrew Gray, Kathryn C. Baer, Christopher Witt |
| Year: | 2021 |
| Type: | General Technical Report |
| Station: | Pacific Northwest Research Station |
| Source: | Chapter 8 In: Barrett, Tara M.; Robertson, Guy C., eds. 2021. Disturbance and sustainability in forests of the Western United States. Gen. Tech. Rep. PNW-GTR-992. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station: 161-189. |
Abstract
Nonnative invasive plants are a potential threat to the sustainability of Western U.S. forests. In the implementation of the Montréal Process Criteria and Indicators, invasive plants are recognized as affecting native species diversity (indicator 1.6), the status of endangered species (indicator 1.7), and the area of forest outside the range of natural variation (indicator 3.15) (Robertson et al. 2011).2 Invasive plants can affect forest ecosystems by reducing the abundance and functions of native species, and they can affect nutrient cycling and the fitness of native plants and animals (Pyšek et al. 2012). Invasive plants can also change the probability of other disturbances, most notably increasing the probability of wildfire (D’Antonio and Vitousek 1992). Because many invasive species are well suited to disturbed and early-seral vegetation conditions, this can set up a positive feedback loop that further degrades native ecosystems. It is estimated that invasive plants cost the U.S. economy $34 billion per year in lost productivity and control and eradication costs, primarily on agricultural lands (Pimentel et al. 2005); a study of selected plants in Oregon forests suggested a cost of $80 million per year (The Research Group 2014).
This chapter assesses the abundance of nonnative plants in Western U.S. forests, draws from the literature to discuss control and eradication efforts and species’ potential impact on forest sustainability, and evaluates options for continued monitoring and understanding of their role in our forests