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South Branch WMA (Merck Tract) Going to the Birds – and Hunterdon County Department of Parks and Recreation

by Mimi Dunne, Sr. Biologist, and
Troy Ettel, N.J. Audubon Society
May 28, 2008

A unique model for management of New Jersey’s public open spaces is emerging via a partnership formed to manage a section of the South Branch Wildlife Management Area. New Jersey Department of Environmental Protection – Division of Fish & Wildlife (DFW), Hunterdon County Dept. of Parks and Recreation (HCDPR), and the New Jersey Audubon Society (NJAS) will collaborate under an agreement signed between DEP and the Hunterdon County Board of Chosen Freeholders giving HCDPR management authority over the Merck Tract (pdf, 500kb) in Raritan, Readington and Hillsborough Townships.

South Branch WMA The NJ Green Acres Program purchased the 423-acre section known as the Merck Tract from Merck and Company, Inc. in 2000. The property straddles the Somerset and Hunterdon county line along the South Branch of the Raritan River. While the State retains ownership of the property, the agreement authorizes HCDPR to manage habitat projects and recreation on the property adjacent to Clover Hill County Park.

NJAS worked with the Division's Bureau of Land Management to develop a draft management plan that outlines a multi-year process to improve and create habitat on the site. While cooperation between government and nonprofit agencies is critical to the project’s success, of equal importance is maintaining a cooperative relationship with the Merck Tract’s existing farmer. The plan’s goals will be achieved in phases that will convert overgrown fields, cropland, and fallow areas into native warm season grass fields interspersed with a mix of annual row crops, cool season hay, and early successional scrub-shrub habitat. The partners are working to establish the farmer as a long-term fourth partner who, in addition to farming the site, will also work with the other partners to implement habitat restoration and maintenance onsite.

NJAS has focused on improving grassland habitat in this region as part of the Raritan Piedmont Wildlife Habitat Partnership (RPWHP), a group of local and state private and public agencies with a common goal of improving habitat for wildlife in its focal region that includes portions of Hunterdon and Somerset counties. A region-wide analysis of potential habitat performed by the DFW – Endangered and Nongame Species Program for the RPWHP identified the Merck Tract as one of the key publicly-owned sites in the region for grassland bird conservation.

The goals of management activities include providing nesting habitat for grassland birds such as bobolink, eastern meadowlark, and grasshopper sparrow, as well as habitat for small game species such as eastern cottontail and American woodcock. The prevalence of grasslands in New Jersey’s landscape has fluctuated greatly in recent history, but this habitat type is currently experiencing unprecedented declines.

Although grassland habitats peaked shortly after the arrival of European settlers who cleared much of the forested landscape for farming, grassland habitats in New Jersey are presently at their lowest levels in the last 13,000 years. An obvious consequence of this decline in habitat has been the steady decline of species dependent upon it. Currently, 48% of birds listed as endangered in N.J. are grassland species, while 28% of those listed as threatened are grassland birds. Presently, as a habitat type, grasslands are in short supply in New Jersey as farmland is converted for housing, or reverts to shrubby woodland, and modern farming places a greater emphasis on increased production and away from practices that allow for undisturbed habitat during the nesting season.

Savannah sparrow
Savannah Sparrow
Click to enlarge

Bobolinks and grasshopper sparrow currently nest in small numbers onsite and eastern meadowlarks can be found on neighboring properties. Other state imperiled or declining birds like prairie warbler, blue-winged warbler, American kestrel and American woodcock will also benefit from the improvements specified in the site plan.

Much of the current site management is the result of sound stewardship practiced by a local farmer who has farmed the property since the 1980s. Areas that he farms represent the best sites on the property, as only these have avoided succession into dense, overgrowth thickets. The farmer will continue to farm under a lease arrangement with the county and is expected to play a vital future role in management of the actively farmed areas as well as those areas managed principally for habitat. In fact, with his assistance, much of the reclamation has already begun.

In the fall of 2007, the farmer did extensive rotary mowing with a tractor. That was followed by a contractor who "hydroaxed" the larger shrubs and trees to prepare the site for seeding. The hydroax is a piece of heavy equipment hired by the state DFW with funds from U.S. Department of Agriculture's Natural Resources Conservation Service under their Wildlife Habitat Incentives Program (WHIP). This specialized equipment can remove trees up to 8" in diameter, and process them into chips. At least 50 acres were treated with hydroaxing, and 40 acres of that are being planted to grasses this spring.

Grassland birds will use both cool season hay (alfalfa, orchard grass, timothy) and warm season grass (big and little bluestem, switchgrass, Indiangrass) for nesting. By planting warm season grass, which is native to the East Coast, the habitat diversity will be improved. WHIP funds will be used to implement future warm season grass plantings. Grassland birds need large patches of suitable habitat, so creating large fields of grass should be attractive to them. They instinctively avoid situations with overhead perches for predators, so removal of out-of-service power lines and poles as well as some of the hedgerows between fields will be a key management objective.

Improving the scrub-shrub early successional habitat will be more challenging than establishing grasslands. On many of the areas that were hydroaxed, invasive exotic vegetation has outcompeted the native trees and shrubs, and will need surveillance and management to keep it in check. Multiflora rose, Russian and autumn olive, Amur honeysuckle and wineberry can grow so dense that they will be impenetrable to human or wildlife passage. The goal is to strike a balance between these invasives and native trees and shrubs, at a density that doesn't deter migratory birds like woodcock from using the area.

Recreational hunting will continue under Hunterdon County's management. Free hunting permits will be available to both county and state residents. Control of white-tailed deer numbers is critical to the success of the contract farmer as well as the restoration project. Without adequate deer control, plantings of native shrubs planned onsite along waterways and in areas slated for early successional habitat management will fail. When deer numbers are too high, they over browse native vegetation suppressing and stunting its growth to the benefit of the less-preferred browse of invasive exotic vegetation. In contrast to cool season hay, deer do not browse warm season grass hay so planting it should have a minimal impact on deer numbers.

NJAS and the DFW cooperated to submit the project for federal funding through the USDA’s Wildlife Habitat Incentives Program. This program is administered through the USDA’s Natural Resources Conservation Service. NJAS has also received funding from private sources including Merck and Co, Inc. and Conservation Resources, Inc. who made a significant contribution for habitat restoration through a grant from the Doris Duke Charitable Foundation. The Gibson Family Foundation and Mushett Family Foundation have also supported NJAS’s work to restore grasslands on public and private lands in the area.

"This partnership helps to stretch scarce public dollars by matching public funds with private grant sources," said Troy Ettel, NJAS Director of Conservation and Stewardship. "In addition it provides a way for non-governmental organizations such as NJAS to assist public agencies such as the DFW and HCDPR fulfill important mission areas that they may not have the time or staff to implement to their satisfaction. Funding for land stewardship and maintenance is grossly inadequate in New Jersey. We welcome the opportunity to work with the state and county to achieve their stewardship objectives and stretch public funding wherever possible to address these growing needs."

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Last Updated: May 28, 2008