A state and local partnership to control invasive water chestnuts in the Nashua River - Photo by Wynne Treanor-Kvenvold

Protecting Native Ecosystems by Combating Invasive Species

Our watershed is home to a wide variety of plants and animals. A few native wildflowers and trees you may be familiar with are the New England Aster (Aster novae-angliae), the Cardinal Flower (Lobelia cardinalis), American Columbine (Aguilegia canadensis), Flowering Dogwood (Cornus florida), White Pine (Pinus Strobus), and Red Maple (Acer rubrum). Landscaping with native species has many benefits including the fact that native species are hardy and attractive to wildlife.

Stomping invasive Japanese knotweed - Photo by Mary MarroNon-indigenous, or non-native, species are those that evolved elsewhere and have been purposely or accidentally relocated by humans or environmental alterations, i.e. climate change. According to the Ecological Society of America, approximately 50,000 non-indigenous species have been introduced into the United States. Not all introduced species become invasive. Some appear to be relatively benign, but others are strong competitors or voracious predators with devastating effects. The Massachusetts Invasive Plant Advisory Group defines “invasive” as “non-native species that have, or are likely to, spread into native or minimally-managed plant systems and cause economic or environmental harm by developing self-sustaining populations and becoming dominant or disruptive to those systems.”1 Invasives crowd out native species, alter natural food webs, and destroy wildlife habitat.

Identifying Asian Longhorned Beetles - Photo from USDA Beetle BustersAlthough much focus is on invasive plants, our region is also dealing with invasive animals, such as the Asian Longhorned Beetle. The Asian Longhorned Beetle, native to Asia, is a destructive pest of hardwood trees, including maple, horse chestnut, birch, poplar, willow, and elm. These beetles were first discovered in Massachusetts in 2008. Since then, the city of Worcester has had to remove some 29,000 infested trees. Areas that are currently being regulated to prevent the spread of the beetles include Worcester, West Boylston, and Boylston, as well as portions of Holden, Shrewsbury, and Auburn. The public is encouraged to report sightings of the beetle or any signs of infestation. More on Asian Longhorned Beetles

NRWA has taken action to address invasives in our watershed by:

  • Identifying and controlling infestations of Purple loosestrife (Lythrum salicaria) in nine communities in our wetlands using biocontrol. About NRWA’s Purple loosestrife control project.
  • Removing over 2,700 tons of Water chestnut (Trapa natans) from the Pepperell Pond impoundment of the Nashua River in Groton/Pepperell area. About NRWA’s water chestnut control project
  • Removing Japanese knotweed on the banks of the North Nashua River (Polygonum cuspidatum) in Fitchburg working with a neighborhood youth group.
  • Providing free presentations on topics such as landscaping with native species, identifying and preventing the spread of the Asian Longhorned Beetle, and how boaters can prevent accidental transport of invasives from one waterway to another.

As the climate continues to change, non-native plants especially invasive ones could become even more widespread and destructive, according to a new Harvard study. The researchers found that some invasive plants have begun to flower earlier in the year as average annual temperatures have gone up. Early growth appears to give them a chance to dominate an area and destroy surrounding wildlife habitat, as well as cause other environmental problem. Invasives will continue to be a focus of NRWA efforts to protect our native ecosystems.

For more information on NRWA programs to control invasives, please contact Kathryn Nelson, NRWA Water Monitoring Coordinator, at (978) 448-0299, or This email address is being protected from spambots. You need JavaScript enabled to view it..

1Massachusetts Invasive Plant Advisory Group. (2005). The Evaluation of Non-Native Plant Species for Invasiveness in Massachusetts. Page 5.

Invasive Plant Species Resources

Ecological Society of America
Massachusetts Invasive Plant Advisory Group
Invasive Plants of the United States: Identification, Biology and Control
Invasive Plant Index of New England
A Guide to Invasive Plants in Massachusetts by MA Division of Fisheries and Wildlife
USDA National Invasive Species Information Center- MA
USDA National Invasive Species Information Center- NH
Field Guide to Common Aquatic and Riparian Plants of NH
Landscaping with Native Species

How to Prevent Spread of Aquatic Invasive by Boats

MA DCR Boatramp Monitoring Program
NH Guide on Transport of Exotic Species on Boats 

Asian Longhorned Beetle Resources

Massachusetts Introduced Pests Outreach Program