The objective of the present study was to compare the invasive vascular plant species at city, state, National Parks, and research preserves in New York, New Jersey, South Carolina and Florida, where the author has conducted research and published his findings in refereed journals. Sites with human activity have a high percent (<50%) of invasive species. Invasive taxa have increased at “protected” sites where human impact is minimal posing a further threat to native vegetation. The deliberate introduction of exotic taxa such as Callery Pear, Kudzu, Multiflora Rose, Norway Maple, Oriental Bittersweet, and more pose a threat to native taxa.