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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 Silent Invasion: Nonnative Trees Threaten American Forests

    • Jan 23, 2024
    • USDA. FS. Southern Research Station. CompassLive.

    • Nonnative tree species are gaining a foothold in forest ecosystems. These trees compete with native species for resources, sunlight, and space. Tree of heaven and Chinese tallow tree are the most invasive tree species in the South, according to a recent study which uses Forest Inventory & Analysis data to create an indicator of nonnative tree regeneration success and can help prioritize the species and locations for treatment. 

  • Garlic Mustard Threatens the Rare West Virginia White Butterfly

    • Mar 9, 2023
    • CAB International. Invasives Blog.

    • Garlic mustard (Alliaria petiolate) is a highly destructive invader in North America. As well as hindering the survival of native plants, it poses a particular threat to the survival of the rare West Virginia white butterfly (Pieris virginiensis).

  • Media Release: IPBES (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services) Invasive Alien Species Assessment

    • Sep 4, 2023
    • Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES).

    • A new scientific report, Summary for Policymakers of the Thematic Assessment Report on Invasive Alien Species and their Control of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, offers the most exhaustive look yet at how nonnative plants and animals can drive extinctions, disrupt food systems and harm human health. The report was compiled by 86 experts from 49 countries, who drew on thousands of scientific studies and contributions from Indigenous people and local communities. Key points:

      • Invasive Alien Species Pose Major Global Threats to Nature, Economies, Food Security and Human Health
      • Key Role in 60% of Global Plant & Animal Extinctions
      • Annual Costs Now >$423 Billion – Have Quadrupled Every Decade Since 1970
      • Report Provides Evidence, Tools & Options to Help Governments Achieve Ambitious New Global Goal on Invasive Alien Species
  • Invasive Species and Climate Change Impact Coastal Estuaries

    • May 5, 2022
    • University of California, Davis.

    • Native species in California's estuaries are expected to experience greater declines as invasive species interact with climate change, according to a study from the University of California, Davis. The study "Biological Invasions Alter Consumer-stress Relationships Along an Estuarine Gradient," published in the Ecological Society of America's journal, Ecology, said these declines are expected not only because of climate-related stressors, but also because of the expanding influence of new invasive predators whose impacts are occurring much farther up the estuary.

  • The Five Drivers of Extinction: Invasive Species

    • Dec 6, 2022
    • Defenders of Wildlife.

    • Over recent decades, globalization has led to an increase in the international flow of people and goods, bringing people together but also bringing together species that have never coexisted before. Species that are introduced and successfully colonize areas outside their natural ranges are considered ‘invasive’ and can have devastating impacts on species native to the region. Invasive species can cause the decline or extinction of native species, outcompeting them for food, water and space, preying upon them or introducing them to new diseases.

  • U.S. Fish and Wildlife Service Reclassifies Northern Long-eared Bat as Endangered under the Endangered Species Act

    • Nov 29, 2022
    • DOI. Fish and Wildlife Service.

    • The U.S. Fish and Wildlife Service announced a final rule to reclassify the northern long-eared bat as endangered under the Endangered Species Act (ESA). The bat, listed as threatened in 2015, now faces extinction due to the rangewide impacts of white-nose syndrome, a deadly disease affecting hibernating bats across North America. The rule takes effect on January 30, 2023.

Selected Resources

The section below contains highly relevant resources for this subject, organized by source.

Council or Task Force
  • Why Should I Care?

    • Georgia Invasive Species Task Force.

    • Invasive species spread either accidental or intentional into new environments has resulted in negative impacts to the ecological communities of infested areas, to commercial, agricultural, aquacultural, and recreational activities dependent on these areas.

Federal Government
State and Local Government
  • Invasive Plants: Impact on Environment and People

    • Apr 2017
    • Purdue University (Indiana). Extension.

    • This Nature of Teaching lesson teaches students about the significant environmental and economic losses that can be caused by the introduction of invasive plant species. It includes a game that can be played in class, plus a worksheet. The lesson meets multiple Indiana science, natural resources, math, and social studies standards

  • Invasive Predators and Global Biodiversity Loss

    • 2016
    • Proceedings of the National Academy of Sciences.

    • Doherty, T.S., A.S. Glen, D.G. Nimmo, E.G. Ritchie, and C.R. Dickman. 2016. Invasive predators and global biodiversity loss. Proceedings of the National Academy of Sciences 113(40):11261-11265.

  • Invasive Species and Species at Risk

    • Invasive Species Centre (Ontario).

    • Protecting ecosystems from degradation caused by invasive species can help protect species at risk and critical habitats. In 2019, the United Nations reported invasive alien species as a top-5 driver of species decline.



  • 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.