NJAS Opinion: November, 2006

New Jersey Audubon Society (NJAS) has been working to conserve, restore and enhance the natural environment of New Jersey since 1897.  For over a century, NJAS has identified threats to our natural heritage and crafted science-based responses to protect our natural treasures for current and future generations.  NJAS recognizes that the threats facing New Jersey’s ecosystems today are more severe than at any other time in history.  Such extreme and extraordinary threats will require strong measures to counteract or mitigate these impacts. Failure to address these threats will inevitably lead to the large-scale loss of biological diversity and ecosystem health.  Although the use of herbicides is not preferred, NJAS recognizes that in ecological restoration and habitat maintenance, use of herbicides may be essential to success and that the long term consequences of losing biological diversity are far more severe than the short term impacts of herbicides. 

NJAS supports the use of herbicides in activities where ecological restoration or wildlife habitat management is the objective and when no other effective alternative is available.

Background

Whenever herbicide use is proposed, a thorough review of the existing literature should be carried out to evaluate the potential impacts of the chemical’s use and to determine if effective alternatives are available. If no alternative treatments are known, the use of chemical control may be explored.  Again, great care should be given to the selection of the herbicide looking at both active and inactive ingredients to determine the product that can successfully control the target plants while minimizing impacts to non-target species and water quality. Furthermore, the product’s half-life (the time it takes for a substance to become inactive) should be considered. Clearly, the product with the shortest half-life in the environment is preferred. Each proposal to use herbicides in restoration or habitat management should evaluate the potential impacts and alternative solutions, and should be decided on a case-by-case basis.  

Used as part of an integrated management plan, herbicides can be very effective in restoration projects or in controlling invasive and exotic species of vegetation that threaten native plant and animal communities.  However, herbicides are only one of the tools available to land mangers for restoration and management of wildlife habitat and should only be used when natural or mechanical methods are not possible or effective.  NJAS' experience has shown the use of herbicides to be effective and appropriate for the control of Phragmites and the management of grasslands.

Phragmites (Phragmites australis) is a wetland plant species that occurs throughout the world.  Although varieties of this plant are native to the eastern United States, an aggressive, non-native strain of Phragmites has more recently invaded New Jersey wetlands, out-competing the native strain.  The growth pattern of this non-native variety is much different than the native variety and can displace native plants and animals.  Because of its invasive nature, Phragmites tends to out-compete native vegetation often resulting in a monoculture, which is an area dominated by a single species, thus lacking diversity. It does so by sending out underground stems called rhizomes which can emerge quite far away from the parent plant. As a result, management of Phragmites requires addressing the plants' subsurface area.  While mowing and fire may be a necessary part of an effective habitat restoration plan, herbicides are effective for Phragmites because the plants will uptake the herbicide and impact the source plants, thereby destroying the Phragmites in a way that fire or mowing alone can not. While a monoculture expanse of Phragmites is generally reflective of a degraded ecosystem, it is important to note that Phragmites can provide suitable habitat for some species of wildlife, such as bitterns and sparrows. Therefore, any management plan that includes Phragmites removal should carefully evaluate the habitat needs of its target species and the impacts of Phragmites removal on species that utilize it. A well balanced management plan will recognize the value of the structure of Phragmites and, depending upon management targets, may include retaining patches of Phragmites within a diversity of habitat types.

Grasslands are disappearing from the NJ landscape. Because many wildlife species of conservation concern are dependent on grasslands in some phase of life, grassland restoration has become a high priority for avian and biodiversity conservation, as identified in NJ’s Wildlife Action Plan. Voluntary conversion of agricultural fields to stands of native grasses is creating important habitat for these species. But successful conversion from agricultural land to grassland often requires the use of herbicides.  The seed bank of an agricultural field tends to be rich in non-native species that out-compete the young native grasses. Thus the use of herbicides that target undesired species of vegetation, but protect native grasses, is a critical tool for effective grassland restoration.  

By contrast, NJAS does not support the use of herbicides in routine maintenance of lawns or roadside vegetation, except where it is used to control invasive, non-native plants. Application of herbicides in maintenance issues is unnecessary because mechanical means to control vegetation is sufficient to achieve maintenance goals. Roadside and lawn maintenance achieve an aesthetic objective, not an ecological goal.  It is NJAS' view that the aesthetic objective does not warrant the introduction of any risk associated with herbicides.