The assessment criteria have been adopted from current available invasive assessments (Fox et al. 2005; Morse et al. 2004; Schutzki et al. 2004; and Warner et al. 2003) and modified for use in the North Carolina horticultural trade. Criteria are those that are likely to have resources and information available for a variety of species. The model is largely non-predictive and not intended to predict invasive attributes or prescreen species not currently utilized in the North Carolina horticultural trade; however, potential for further spread of existing species is considered.

• Project Description
• The Assessment Tool
• Summary of Results
• Detailed Species Results
• Economic Impact Analysis
• Model Development
• Model Comparison
• Resources

Project Description

An Invasive Species Assessment System for the North Carolina Horticultural Industry was developed by Clara Trueblood as part of a Master’s Thesis project in the Department of Horticultural Science at North Carolina State University.

The North Carolina Nursery and Landscape Association (NCNLA) supported the development of an invasive assessment protocol designed to systematically assess the potential invasiveness of ornamental plants suspected to affect natural areas in North Carolina.

The North Carolina protocol incorporates and builds upon elements of existing assessment models to evaluate the potential invasiveness of plant species in accordance with regional environmental conditions.

The North Carolina assessment criteria are based on a framework of weighted sets of indices that evaluate and rate:

• Ecological Impacts
• Current Distribution and Potential for Expansion
• Management difficulty
• Benefit and Value

According to the combined weighted results, the model generates a recommendation for evaluated species ranging from ‘unlikely to be invasive’ to ‘invasive and not recommended for use.’

The assessment model incorporates a unique cost/benefit analysis and weighs economic benefits against the ecological risk of selling potentially invasive ornamental plants (Economic Impact Analysis).

The assessment protocol was used to evaluate the invasiveness of 25 nonnative taxa (Summary of Assessment Results).

By modifying the criteria utilized in existing assessments and tailoring the model for the North Carolina horticultural trade, we have created an assessment system unique to the nursery industry that may be completed using resources available in North Carolina.

The assessment results are intended to allow the NCNLA to advise their members regarding plants that are purported to be invasive.

For additional background information, please see the Project Scope and Justification.

Detailed Species Results

The invasive species assessment system for the North Carolina nursery industry provides detailed species evaluations and associated assessment points.

Resources

Literature Databases

• AGRICOLA
• CAB Abstracts

Journals

• Biological Invasions
• Diversity and Distributions
• Invasive Plant Science and Management
• Weed Biology and Management
• Weed Technology

Current Federal and State Regulations

• USDA – APHIS Noxious Weeds Program
• North Carolina Department of Agriculture and Consumer Services Plant Protection Section

Ecological Impact

• North Carolina Natural Heritage Program
• U.S. Fish and Wildlife Service (Threatened and Endangered Species)

Distribution and Potential for Expansion

• EDDMapS
• Flora of the Carolinas, Virginia, and Georgia, and Surrounding Areas
• NCU Flora of the Southeastern United States
• USDA PLANTS Database
• Non-native Invasive Species (NNIS) in Southern Forests

General Resources

(Ecological Impact, Distribution, and/or Management Difficulty)

• Global Invasive Species Database
• Invasive.org
• The National Invasive Species Council
• The Nature Conservancy
• The Nature Conservancy – Element Stewardship Abstracts (ESAs)
• NatureServe Explorer
• Nonnative Invasive Plants of Southern Forests
• North Carolina Exotic Pest Plant Council
• Plant Conservation Alliance
• Southeast Exotic Pest Plant Council Invasive Plant Manual
• Southern Appalachian Man and the Biosphere (SAMAB)
• University of Florida Center for Aquatic and Invasive Plants

Assessment Systems

• California Invasive Plant Council
• IFAS Assessment of Non-native Plants in Florida’s Natural Areas
• Michigan Invasive Plant Council
• NatureServe