Invasive Plant Identification and Control Along the Wild and Scenic Delaware River Corridor Bull ’ s Island and The Field at Fireman ’ s Eddy Initiatives by Delaware River Greenway Partnership Proposal to the Lower Delaware Wild and Scenic Management Committee October, 2009 Introduction and Background The Lower Delaware River is one of fewer than a dozen National Wild and Scenic Partnership Rivers – rivers designated by Act of Congress, but owned and managed by individuals and communities along their banks. A management plan, written in 1999, and updated in 2007, outlines goals and implementation strategies to preserve its outstanding natural resources and water quality. Three major action areas are of greatest concern in the immediate future: water quality assessment, community education, and invasive plant control. Invasive plants, both well known and long established populations, as well as emerging species, constitute a serious and growing concern in the river corridor. They present problems along both New Jersey and Pennsylvania sides of the river and their parallel canal corridors. In their book, Plants of Pennsylvania (University of PA Press, 2000) Rhoads and Block cite Lythrum salicaria, (purple loosestrife) and Polygonum perfoliatum (mile-a minute) as noxious weeds in the state, and mention Microstegium vimineum (Japanese stiltgrass) and Polygonum cuspidatum (Japanese knotweed) as aggressive weeds spreading rapidly. In addition, Japanese hops ( Humulus japonicus) has been listed by both the ( Pennsylvania Department of Conservation and Natural Resources (PADCNR) and the Central Jersey Invasive Species Strike Team (CJISST) as highly threatening to native ecosystems and spreading rapidly. The rapid spread of these invasive weeds cause a reduction in native floral and faunal biodiversity. Knotweed, in particular, is poisonous to some native pollinators, with serious implications for agriculture. In inhabited areas, it can cause damage to buildings, roads and other infrastructure, resulting in extensive costs to governmental and private entities.
Nearly ten years after the publication of Plants of Pennsylvania, the situation is worse. In some locations, well established populations of the above have formed extensive monocultural colonies and present formidable challenges to extermination. In other sites however, particularly where portions of the canal towpaths and low lying floodplain have been scoured by recent flooding, relatively uncolonized soils offer opportunities for restoration with appropriate native species in order to preclude encroachment by invasives. Yet other areas may be minimally affected by known invasives, and will respond positively to simple eradication techniques.
Several projects have already been completed or are in progress. Invasive and emerging invasive species have been greatly reduced in Washington Crossing State Park (NJ). A Delaware River Invasive Plant Partnership (DRIPP) pilot program against Japanese knotweed (P. cuspidatum) developed a successful treatment protocol, and eradicated the plant from the lower Tinicum Creek, a designated tributary to the W&S Delaware. Efforts to eradicate mile-a-minute (P. perfoliatum) are ongoing. Several riparian restorations along Tinicum and other designated tributaries have been very successful.
A study of the Giving Pond Recreation Area in 2006, funded by the NPS through the W&S Management Committee ’s Municipal Incentive Grant Program, documented the non-native and invasive species in the park, and suggested control measures, which could form the basis for additional removal and restoration projects.
Central Jersey Invasives Species Strike Team ( CJISST) has identified and is working towards eradication of 71 emerging invasive species from publicly held lands in Central New Jersey (See www.cjisst.org for additional information on this project). A pending grant application to identify and remove emerging invasive plants along recently restored sections of Pennsylvania ’s Delaware Canal, and replant the canal banks with native vegetation represents a partnership of several non-profit and governmental entities, of which Delaware River Greenway Partnership (DRGP) is one.
DRGP intends to expand and build on these beginnings. Numerous opportunities for partnership and citizen involvement and education exist. We intend to educate the public and engage it in the problems of invasives control and natural riparian buffer improvement, and to cooperate with governmental and non-governmental organizations to accomplish these restoration and educational goals.
The current project is designed to remove invasive species and restore native vegetation at two sites administered by the Delaware and Raritan Canal State Park (D&RCSP). Primary partners for the project are Partners for Fish and Wildlife, US Fish and Wildlife Service (USFW), Delaware River Greenway Partnership (DRGP), and the D&D Canal State Park, Division of Parks and Forestry, NJDEP. Assisting with the project are CJISST, Washington Crossing Audubon Society, Bowman ’s Hill Wildflower Preserve, Delaware River Scenic Byway, and the D&R Canal Watch.
Site Locations
The Delaware and Raritan Canal State Park occupies most of the area between the river and Route 29, very recently designated a National Scenic Byway, from Frenchtown to Washington Crossing State Park
Bulls Island Sitting in the lower middle section of the corridor, the Bull ’s Island Recreation Area of the D&R Canal State Park is defined by the river on one side and the canal on the other. The 79-acre island is subdivided into three areas, two of which are devoted to office and maintenance buildings, parking, bridges, and camp sites. The third is a forested 34-acre state designated Natural Area, which occupies the southern end of the island.
This natural area is well documented by NJ Audubon and others as a hot spot for spring migrants, particularly warblers, and a valuable nesting site. The pedestrian bridge provides nesting sites for swallows, including the rare rough-winged swallow, and these birds plus migrating waterfowl are a draw for avid birders. Bird populations have been declining, however, and habitat degradation from invasive non-native species incursion is a major contributor to this decline. Strict Natural Lands guidelines will govern any control and planting in this area.
Flood scouring has opened much of the northern end of the river side of the island to possible alien plant invasion, making this site especially promising for proactive riparian restoration and erosion control.
The Field below Fireman ’s Eddy The other site is a 75 acre field owned by the D&RCSP in Hopewell Township and adjacent to Fireman ’s Eddy Bridge. Although several native grassland forbs are present, e.g., wingstem (Verbesina alterifolia), milkweeds, (Asclepias sp.), snakeroot (Sanicula sp.), jewelweed (Impatiens capensis), and others, the field is increasingly dominated by invasive shrubs and brambles, particularly autumn olive (Elaeagnus umbellata), black locust (Robinia pseudoacacia), and multiflora rose ( Rosa multiflora). The site has considerable historic interest as an early Native American seasonal camp. Restored as a grassland, and with appropriate interpretive materials, it could be a valuable asset to the National Delaware River Scenic Byway, as it has great potential as habitat for endangered grassland birds.
Prior botanical surveys have resulted in native plant lists for the Bull ’s Island site. More recent snapshot surveys by CJISST experts and volunteers have produced lists of invasive plants of concern in both sites. A Plant Stewardship Index inventory of both areas sponsored by Bowman ’s Hill Wildflower Preserve under a Franklin Parker grant is set for Spring, 2010. (See appendix for survey lists)
Scope of the Projects
Upland and Palustrine Restoration Plan – Bulls Island
The project is located in the Bulls Island section of the D&R CSP in Delaware Township, Hunterdon County, New Jersey on the Wild and Scenic Lower Delaware River. The proposed upland restoration project within the Bulls Island Natural Area will restore approximately 5 acres of upland and palustrine forested and shrub/scrub habitat by controlling invasive Japanese knotweed (Polygonum cuspidatum) and Japanese hops ( Humulus japonicus ) and planting native shrubs and trees.
Currently, P. cuspidatum monocultures cover at least 5 acres in separated patches, and Japanese hops is widely present in isolated clusters. To control these invasives, knot weed will be cut in June or July to reduce the vegetative height, and make herbicide treatment more effective, and herbicide treatments with a glyphosate-based herbicide will be applied in late August or early September of 2010 and 2011 to obtain initial control. This is the method preferred by NJ DEP. An alternative protocol involving stem injection of herbicide has been successful, and may be utilized. (1,2) Treatments will not interfere with amphibian and reptile breeding times, and will follow Natural Land Trust protocols. Cut knotweed will be removed from the site in plastic bags, and disposed of after thorough solarization.
In the spring of the third year, or once the knotweed and hops have been eliminated, native trees and shrubs will be planted in the natural area. Appropriate species for both areas may include dogwood (Cornus ssp), river birch (Betula nigra), willow (Salix ssp), pin oak (Quercus palustris), arrowwood viburnum (Viburnum dentatum), winterberry (Ilix verticillata), serviceberry (Amelanchier ssp), red chokeberry (Aronia arbutifolia), and buttonbush (Cephalanthus occidentalis).
Riparian buffer plantings with native species, preferably willows and dogwoods, will be done in the first year on the flood cleared areas on the upper half of the island to provide competition to possible invasives and provide a riparian buffer.
Some spot treatments may be required in subsequent years to insure that the invasives do not reinvade the project area. The USFW Service will provide trees and shrubs, appropriate herbicides, and oversight for licensed applicators from D&R Canal State Park and other personnel, as well as overall project assistance for the duration of the project.
Old Field Restoration Site D&R Canal State Park – Fireman ’s Eddy Bridge
A 75-acre field in Hopewell Township, Mercer County, south of Lambertville within the Delaware and Raritan Canal State Park, is currently dominated by old field vegetation and scrub/shrub habitat. This site is large enough and appropriately located to provide important resting, foraging, and nesting habitat for migratory grassland dependent birds, such as the state-listed endangered vesper sparrow (Pooecetes graminus) and threatened bobolink (Dolichonyx oryzivorus) and grasshopper sparrow (Ammodramus savannarum). Invasives present include autumn olive, mugwort, black locust and others; these threaten to dominate the field in time, rendering it useless for both native plants and grassland birds. The USFW Service and its Cooperators (DRCSP, DRGP) propose to convert this field to native warm-season grasses in the spring of 2010.
Through coordination and technical assistance from the USFW Service, DRGP and Park personnel (the Cooperators) will engage a contractor to remove invading brush, cut field vegetation, remove the resulting debris, prepare the soil, selectively apply herbicides, and seed with native grasses. USFW will provide blue bird houses, approximately 525 pounds of native grass seed, a mix of big bluestem (Andropogon gerardii), Indiangrass (Sorghastrum nutans), switchgrass (Panicum virgatum), and little bluestem (Schizachyrium scoparium), and a no-till grass drill for installation of the seed. USFW Service will also provide technical assistance as needed for the project. A complete estimate of the cash and in-kind costs provided by USFW is included below.
In addition to the initial efforts, including field preparation, herbicide application, seeding, planting, and maintenance, for which the cooperators are responsible, park personnel will be responsible for the long term maintenance of the replanted area and future spot herbicide application, if needed.
Both USFW and a private consultant recommend that this work be done by experienced professionals with cooperative assistance by volunteers. Equipment will be leased from USFW Service, bought, borrowed, or rented, as necessary. (See estimated costs).
Public Outreach
Much of the value of these projects lies in their use as demonstrational and educational opportunities. Photographic documentation of all stages of the projects will be made for use in press releases, on websites, and Power Point presentations. Both temporary and permanent interpretive signs will be erected to explain the projects to the public. Size and placement will be at the discretion of canal park personnel. Volunteer training will be provided. At least one workshop and/or public presentation on identification and control of invasive species is planned. (See estimated costs.)
Costs
A complete budget covering all costs for the three year project follows. See also the attached USFW statement of project costs. DRGP requests a total of $29,200 from Wild and Scenic River appropriations to complete these projects. An additional $1500 in donated volunteer time is anticipated; this is in addition to the materials, labor, and supervisory services proved by USFW.
Deliverables
Photographic documentation of all stages of the project.
Final report to the Wild and Scenic Management Committee.
Interim reports, at least annually, or as requested by NPS.
One public presentation or workshop, location, time to be decided.
Web site interpretation and education for the duration of the project and into the future.
Restored upland and palustrine forested areas with a NJ State designated Natural Area
Creation of 75 acres of warm season grassland habitat.
Restoration of riparian buffer along the Wild and Scenic Delaware River at Bulls Island Recreation Area
Future Plans
At the end of the three year period, the park service (DRCSP) will assume responsibility for maintaining the restoration by mowing every two to three years and controlling deer populations, if necessary, to protect the installations. The Park and DRGP will sign a Memorandum of Understanding with the park service to this effect.
DRGP further intends to seek additional opportunities and partnerships for invasive plant eradication/control and riparian restoration on both sides of the Delaware, and for education of the wider public about the nature and extent of the problem, the importance of invasive species control, and the value of native plants for the Delaware River ecosystem. This effort might include hiring a professional botanist to conduct targeted surveys along the lower Delaware, identify priority sites for control and restoration, and recommend future projects.
Attachments Total Project Budget Abbreviated Timeline USFW statement of budget costs. Plant list and Recent Survey data
www.stopknotweednj.com
Plainfield, NJ. Larry Murrell. www.stopknotweednj.com |