Non-native invasive plant species pose a major threat to critical habitats that are essential for the health of native plants and wildlife. The control and elimination of these plants from the FLCA and surrounding areas is one of the BBC’s most important objectives. Our efforts in this sphere include workdays targeted to the hand removal of certain species, attendance at workshops on control methods, and the use of herbicides to combat specific invasive plant infestations.

To better understand the type and distribution of invasive plant species, several BBC members compiled an “invasives map” of the FLCA 15 years ago that identified the locations of major stands of multiflora rose, spotted knapweed, glossy buckthorn, asiatic bittersweet, Japanese knotweed and common reed (Phragmites), as well as isolated incidences of a number of other non-native plant species. In addition, we noted that water chestnut, the sole aquatic invasive in Fitzgerald Lake, had become established at several sites throughout the lake. Our efforts to combat several of these unwelcome visitors are described in the following.

Water Chestnut

For over a dozen years, we have pulled water chestnut by hand from Fitzgerald Lake. Although we managed to keep this invasive in check, a fairly large infestation persisted. In the summer of 2017, we instituted a new regime in which a flotilla of kayaks, canoes and rowboats went out onto the lake at three-week intervals from June through September to remove water chestnut plants. That summer 25 volunteers spent over 150 hours on the lake, pulling almost 1,100 lbs. of the invasive. Using the same approach, we harvested 300 lbs. in 2018, 140 lbs. in 2019, 178 in 2020, 100 in 2021 and hope to see a further reduction in 2022. Though we have taken a significant step in controlling the growth of water chestnut in the lake, we plan to continue our intensified efforts in the future as water chestnut seeds persist for many years and we want to make sure that these plants do not re-establish themselves.

Phragmites

Phragmites austrailis, or common reed, forms dense, 8- to 10-feet tall stands that choke out native plant species and diminish the usefulness of the marshland habitat for wildlife. Work on the control of Phragmites, which occurred in four stands covering about an acre of the Broad Brook wetlands downstream from the wildlife blind, was initiated by cutting the dormant stalks in the winter of 2009. This was followed by a specifically targeted application of a glyphosate-based herbicide to suppress new growth in late September and early October. Repetiton of the herbicide treatment over the subsequent 5-6 years almost completely eliminated two of the Phragmites stands and greatly reduced the others. Since that time, the wetlands are checked every year and any re-emergent plants are treated as appropriate. Overall, we estimate that we have eliminated about 90-95% of the Phragmites that was present in the Broad Brook marsh ten years ago.

Knapweeds and Buckthorns

We began to systematicslly combat several other problematic plant invasions in 2010. In view of the surprisingly rapid increase of Spotted and Brown Knapweeds, and of Glossy and Common Buckthorns, in Cooke’s Pasture and on the dam, we decided that these species should be the next ones targeted for control.

Knapweeds readily crowd out native grasses and thereby reduce native plant biodiversity. The challenge in knapweed control stems mainly from their prolific seed production. In dense stands, the seed yield has been estimated at close to 150,000 seeds per square meter and 30% of the seed has been found to remain viable after eight years of burial in the soil. Yearly treatment of individual knapweed plants with triclopyr herbicide has resulted in almost complete suppression of these invasives.

Buckthorns are invbasive shrubs or small trees that leaf out early in the growing season and shade out adjacent native plants. With time, they can become monocultures that adversely alter the ecology of pastureland. If not treated, buckthorns spread aggressively via an extensive root system that give rise to new sprouts, as well as by the dispersal of seed by birds and other wildlife. Over 95% of the buckthorn in Cooke’s Pasture has been suppressed through annual, targeted spraying with triclopyr. We have also eliminated a major source of buckthorn seed by cutting and treating a number of mature buckthorn trees growing in the forested buffer zone between Cooke’s Pasture and the Broad Brook marsh.

Grants

Since 2008, BBC has been successful in obtaining a number of grants to fund the control of invasive plants in the FLCA. We are indebted to the Wildlife Habitat Incentives Program (WHIP) of the Natural Resources Conservation Service (USDA), the Massachusetts Land Trust Coalition’s “Empowering Local Land Trusts in Western Massachusetts Western Massachusetts” Program, and Northampton’s Community Preservation Award Program, which has made much of the work in Cooke’s Pasture and the Broad Brook marsh possible, for their generosity and support