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.