Invasiveness Rankings

In 2008, The Nature Conservancy in New York and the Brooklyn Botanic Garden developed a system and protocol designed to assess the invasive nature of non-native plant species. The New York State Invasive Species Council, in consultation with the Invasive Species Advisory Committee, adopted the ranking system for use statewide. In addition, results of this work have informed invasive species legislation in Nassau and Suffolk Counties. 

 In 2013, the New York State Department of Environmental Conservation (NYSDEC), and consultants with Adirondack Research, Inc., utilized three modified versions of the plant assessment protocol to assess the invasive nature of non-native animal species. This work was conducted in preparation for the development of invasive species regulations on behalf of the New York State Invasive Species Council, with consultation from the Invasive Species Advisory Committee. Animal species are assessed at a statewide level using one of three separate assessment forms, Terrestrial Vertebrate, Terrestrial Invertebrate, or Fish and Aquatic Invertebrate. 

 Consequences to the native species and natural ecosystems of New York are the focus of the ranking system. The ranking system is designed to be repeatable, based on the best available science, clearly explained, and fully documented. The system can be used to assess non-native plant and animal species that are established in New York State, species that are new arrivals, as well as species that are not yet present. 

 Species assessments are reviewed, edited, and approved by a committee of stakeholders designated as the Scientific Review Committee. Voting members of the committee include scientists, nursery professionals, Cornell Cooperative Extension and land managers at the County, State and Federal levels. A supplemental review is conducted by qualified specialists throughout the State prior to submission to the Advisory Committee and Council for final approval.

New York Invasive Plant Ranks 

 Questions are organized into four broad categories: 

  1. Ecological impact 
  2. Biological characteristic and dispersal ability 
  3. Ecological amplitude and distribution 
  4. Difficulty of control 

Here is the form used for assessing plants at a statewide level:  

New York State Invasive Plant Assessment Form 

For more specific local efforts, the below form can be used in addition to the statewide form: 

PRISM Invasive Plant Ranking Form 

Additional information pertaining to the assessment process can be found in the below resources: 

Animals: A Regulatory System for Non-Native Species 

Plants: New York State Ranking System for Evaluating Non-Native Plants for Invasiveness 


The NYSDEC has published draft invasive species regulations for public comment. The associated documents are available on the Department’s Lands and Forests Emergency, Proposed & Recently Adopted Regulations. 


To View the Assessments: 

Plant Assessments 

Animal Assessments