Environmental and Ecological Impacts
Invasive species can impact both the native species living within an ecosystem as well as the ecosystem itself.
Native species populations can be directly affected through predation, herbivory, and disease (Simberloff 2013). For example, the brown tree snake (Boiga irregularis) caused the extirpation of nine species of bird on Guam, and the hemlock woolly adelgid (Adelges tsugae) has caused widespread mortality of eastern hemlock trees by feeding on its sap (Simerloff and Rejmánek 2011).
Indirectly, invasive species may cause native species declines due to resource competition and habitat alteration (Davis 2009). For instance, plant invasions have been demonstrated to alter carbon and nitrogen cycles and fire regimes in invaded ecosystems (Simerloff and Rejmánek 2011). The invasion of downy brome (Bromus tectorum) in Western U.S. grasslands has led to an increase in the frequency and intensity of wildfires (Simerloff and Rejmánek 2011), and saltcedar (Tamarix spp.) makes the soil inhospitable to native species by depositing large amounts of salt into the surrounding soil (Bell et al. 2002).
See also: General Invasive Species Impacts
The section below contains highly relevant resources for this subject, organized by source.
Council or Task Force
State and Local Government
- Bell, C.E., B. Neill, J.M. DiTomaso, et al. 2002. Saltcedar: a non-native invasive plant in the Western U.S. (PDF | 505 KB) University of California, Weed Research & Information Center. WRIC Leaflet #02-2.
- Davis, M.A. 2009. “Impacts of invasions.” In: Invasion Biology. Oxford: Oxford University Press.
- Simberloff, D., and M. Rejmánek, eds. 2011. Encyclopedia of Biological Invasions. Berkeley, Calif.: University of California Press.
- Simberloff, D. 2013. Invasive Species: What Everyone Needs to Know. New York: Oxford University Press.