Invasive species are plants, animals, pathogens, or other species that have been introduced—either intentionally or by accident—into areas outside their natural ranges. Unchecked by natural controls, invasive species are spreading across our lands and through our waterways, and wreaking havoc with already fragile native species and ecosystems. Invasive species are now regarded as the second-leading threat to imperiled species, behind only habitat destruction.
NatureServe developed the Invasive Species Assessment Protocol, a detailed analytical method that assesses the comparative impact on biodiversity of specific non-native plants. Assessing non-native plants using this protocol yields an Invasive Species Impact Rank (I-Rank); a blank data form and score sheet are also avaible for download. The New York Natural Heritage Program developed iMapInvasives, an on-line, GIS-based data management system to assist citizen scientists and natural resource managers working to protect natural resources from the threat of invasive species.