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What are native species?

A native species is one that occurs in a particular environment without human intervention. Species native to North America are generally recognized as those occurring on the continent prior to European settlement. Non-native (alien, exotic) species are introduced by people, from other continents, ecosystems, or habitats to places where they do not occur naturally.

Non-native invasive plant species are alien species likely to cause economic or environmental harm with a serious and measurable ecological impact due to their introduction.

Invasives often thrive quickly dominating new environments as there are no natural controls, e.g., predation, to keep them in check (  Many invasives have one or more of the following characteristics: 1) adaptation to disturbance; 2) broad tolerance for environmental conditions and extremes of light, soil acidity, and moisture; 3) production of large numbers of seeds; 4) high seed germination success; and 5) the ability to spread by ground runners or rhizomes.


Invasive Plants Home

What is biodiversity and why is it important to us?

Why are invasive plants a problem in natural areas?

How are invasive plants introduced? 

How do invasive plants spread? 

How you can prevent the spread of invasive plants 

Herbicide Use

Re-Plant cleared areas 


Invasives in Washington Twp.






Additional Resources

National Park Service Plant Invaders brochure 

Invasive Species Library

Invasive Plants Home Page

Invasive Species Strike Team APP