As per Executive Order 13112 (Section 1. Definitions) an "invasive species" is a species that is:

1) non-native (or alien) to the ecosystem under consideration and,

2) whose introduction causes or is likely to cause economic or environmental harm or harm to human health.

Non-native species are plants and animals living in areas where they do not naturally exist. "Non-native species" and "invasive species" can not be used interchangeably. Many commonly grown fruits and vegetables are not native to the U.S. For example, tomatoes and hot peppers originated from South America, while lettuce was first grown by the Egyptians. Domestic cows are non-native to North America and were introduced as a food source, and considered to be a beneficial organism in an agricultural setting.