By Amy Smagula, Limnologist, NH Department of Environmental Services
The DES Exotic Species Program coordinates activities associated with the control and management of exotic aquatic plants; as well as activities associated with the implementation of education programs and volunteer plant monitoring programs.
Exotic aquatic plants, such as milfoil and fanwort, have been a problem in New Hampshire lakes and ponds since the mid-1960s. Variable milfoil, by far the most wide-spread exotic aquatic plant in NH, was first found in Moultonborogh Bay in Lake Winnipesaukee. From there it has spread to infest 38 waterbodies. Fanwort, water chestnut, Eurasian milfoil, purple loosestrife, and common reed are also problematic species in this state. There are 950 lakes and ponds greater than 10 cares in NH, and 71 are infested with some type of invasive (this does include some river systems too). This means approximately 7% of our lakes are infested.
Why are these plants such a problem? Native plant communities have evolved together over hundreds of years. Animal and insect grazers have become specialized to feed on these native plants. Since exotic plants are introduced from outside of the state, they have no established relationships with native fauna that would keep their growth in check. When these exotic plants grow without natural controls they encroach into and replace the habitats of native plants, disrupting the food chain, stunting fish growth and degrading wildlife habitat.
Other states besides NH are also faced with the problem of exotic
plants, and unfortunately, no one has yet found a practical,
ecologically sound means of eradication for these plants. Once in a
waterbody, continuous management and control practices are the only
tools to control the nuisance plant growth.
It therefore becomes increasingly more important to prevent
infestations, and to identify new infestations early. DES biologists
conduct numerous field investigations each summer, but with over 800
lakes and ponds in the state, the efforts of volunteers in monitoring
waterbodies for new infestations become critical. Through materials and
training sessions by DES, numerous lakes and ponds have initiated their
own Volunteer Weed Watching programs.
For more information, please contact the Exotic Species Coordinator at 603-271-2963 or
Amy P. Smagula Limnologist/Exotic Species Program Coordinator NH Department of Environmental Services 29 Hazen Drive, PO Box 95 Concord, NH 03302-0095 Phone: 603-271-2248 Fax: 603-271-7894 E-mail: asmagula@des.state.nh.us
Purple Loosestrife(Lythrum salicaria) is an herbacious, wetland perennial that grows in a wide range of habitats. It can reach the height of 5-6' on 30-50 square, woody stems, topped by bright magenta-purple flower spikes. Each plant can produce more than 2 million seeds annually. This plant can easily adapt to any type of wetland, and crowds out native vegetation, forming a monotypic stand. In turn the plant chokes out native fish, insects, birds, other plants and wild animals, and can fill waterways. Contact the NLRA to learn how to remove this plant properly so that seeds are not further dispursed. Purple Loosestrife substitutes
Spiked Speedwell (Veronica Spicata)
Pink Turtlehead (Chelone oblique)
Joe-pye-weed (Eupatorium fistulosum)
Queen of the prairie (Filipendula rubra)
Gayfeather (Liastris spicata)
Swamp rose mallow (Hibiscus palustris)
Purple coneflower (Echinacea purpurea)
Bee balm (Monarda didyma)
Burning Bush substitutes
Enkianthus campanulatus – excellent red foliage
Highbush blueberries
Rhododendron periclyminoides
Physocarpus opulifolius – red color all season
Good news from the NH Department of Transportation (DOT)! The DOT has just produced a control manual for invasive
plants, intended for DOT folks and others like town Department of Public Works. It contains
information about best management practices to reduce the likelihood of
introducing invasive plants into new areas via maintenance and construction
activities.
NH DOT is now preparing hard copies for its staff, and also planning training sessions.
This fulfills a recommendation of the new Water Resources chapter of the Connecticut River Management Plan.
Please share with your town's road crew or
selectboard. (those on dial-up might want to wait until the hard copies are
available).
