Invasive Species Impact Rank

NatureServe Invasive Species Impact Rank (I-Rank)

To respond to the ever-increasing threat of non-native, invasive plant species, NatureServe, in collaboration with The Nature Conservancy and the U.S. National Park Service, developed a protocol for assessing and categorizing non-native plants according to their impacts on native biodiversity. The protocol, published in 2004, was designed to focus specifically on the effects non-native plant species have on native plants, animals, and ecosystems and to make the assessment process objective, transparent, and systematic. It was applied to non-native plants as they occur over a large area, such as a nation, ecoregion, province, or state.

NatureServe used the protocol to assess the impact of selected non-native vascular plants on the natural biodiversity of the United States. While I-Rank information remains available over NatureServe Explorer, NatureServe is not actively developing or maintaining these data. NatureServe continues to provide these data to serve as a reference; however, the data may not represent the current understanding of the effects and management of the invasive species. Since species with I-RANKs do not represent a random sample of species exotic in the United States; available assessments may be biased toward those species that had higher-than-average impact at the time of the assessment.

NatureServe and the Natural Heritage Network have adopted a new tool to manage non-native invasive species. This tool, called iMapInvasives, is an on-line, GIS-based data management system used to assist citizen scientists and natural resource professionals working to protect our natural resources from the threat of invasive species.


Copyright 2018
State and provincial distribution data sources. The Heritage Conservation Status Rank System and Definitions. Name sources for plant, animal, and ecological communty records in NatureServe.