New Hampshire Invasive Species Committee

What are invasive species?

Throughout the United States and Canada, non-native invasive species have become an overwhelming problem 

resulting in impacts to the natural environment and managed landscapes. Invasive species typically possess 

certain traits that give them an advantage over many native species. The most common traits include the 

production of many offspring, early and rapid development, adaptability and tolerance of a broad range of 

environmental conditions and, there are no natural controls to keep them in check. These traits allow invasive 

species to be highly competitive and, in many cases, suppress native species. Furthermore, studies have shown 

that invasives can reduce natural diversity, impact endangered or threatened species, reduce wildlife habitat, 

create water quality impacts, stress and reduce forest and agricultural crop production, damage personal 

property, and cause health problems. 

What is the Invasive Species Committee?

The Invasive Species Committee (henceforth referred to as the Committee) is a volunteer group of nine 

appointed members who meet on a monthly basis to address invasive terrestrial plants, insects, and fungal 

species and their effects upon the state and its natural and economic resources. The efforts of the Committee 

include, but are not limited to the following: prepare and publish a list of Prohibited Invasive Species and a list 

of Restricted (Watch) Invasive species; establishing means by which that state shall minimize such adverse 

effects; promote research and educational activities so as to achieve the best possible protection of agriculture, 

forest, wildlife, and other natural resources of the state and of human health; and to prevent and control the 

spread of invasive species in the state (refer to RSA 430:51 through RSA 430:57). 

What are the criteria used to determine invasive species in New Hampshire?

The Committee developed and utilizes two sets of criteria to evaluate individual species of plants, and insects 

(fungi will be done at a later date). The two criteria are as follows: 

1. Criteria for Prohibited Invasive Plants in New Hampshire and, 

2. Criteria for Prohibited Invasive Insects in New Hampshire. 

 Purple loosestrife Hemlock woolly adelgid Variable milfoil 
What species are considered invasive in New Hampshire?

The Committee is required to prepare annually, two lists for the Commissioner of Agriculture to publish. These 

lists include: 

1. The “New Hampshire Prohibited Invasive Species List”, (being proposed as of May, 2003) is a list of 35 

invasive plants and 16 insect species deemed to present an immediate danger to the health of native 

species, to the environment, to commercial agricultural or forest crop production, or to human health. 

Included in this list are 14 aquatic species that are regulated by the Department of Environmental 

Service’s Aquatics Program; and 

2. The “New Hampshire Restricted Invasive Species List”, (being proposed as of May, 2003) is simply a 

“Watch” list of 16 species that have been shown to be invasive in nearby states, but do not meet the 

criteria established by the ISC. All species on this list will be reevaluated periodically and the list 

revised as needed. The ISC recommends that there be no restrictions for any species placed on the 

Restricted (Watch) list. 

Why are landscape plants such as Norway maple, Japanese barberry, and Burning 

bush considered invasive in New Hampshire?

Although these species have traditionally been heavily used for ornamental landscapes, they still possess all of 

the characteristics attributed to “invasive species”. In several New England states, these species have caused 

significant impacts to the natural environment, which has resulted in the loss of habitat and the decline of native 

species diversity. These species were evaluated by the Committee in accordance with the criteria and were 

found to pose an immediate danger to the state and, therefore, are being proposed as prohibited (Click on

Norway maple, Japanese barberry, and Burning bush to see more). 

What types of regulations will apply to invasive species in New Hampshire?

The New Hampshire Department of Agriculture and the Committee are currently participating in the 

Rulemaking process to develop regulations for addressing invasive species here in New Hampshire. The more 

significant DRAFT Rules, as currently proposed, are as follows: 

1. Adopt the “New Hampshire Prohibited Invasive Species List” into Rule as of January 1, 2004; 

2. Prohibit the collection, importation, transportation, sale, propagation, transplantation or cultivation by 

any person of any species listed on the “New Hampshire Prohibited Invasive Species List” (except for 

Norway Maple, Burning Bush and Japanese Barberry) as of January 1, 2004; and, 

3. Prohibit the collection, importation, transportation, sale, propagation, transplantation or cultivation by 

any person of Norway Maple, Burning Bush and Japanese Barberry as of January 1, 2007. 

Once the Rules are finalized, adopted and become effective, the complete set of Rules will be posted on the 

website.