Assabet River NWR Final CCP - U.S. Fish and Wildlife Service

Japanese Knotweed: Photo by Marijke Holtrop
Chapter 4: Management Direction
mission, goals, and objectives are compatible, will work together to
implement habitat management and biodiversity strategies.
Objective 3: Limit the spread of invasive and overabundant species and
minimize habitat degradation.
Strategy 1: Document presence, acreage, and location of invasive and
overabundant species in conjunction with vegetation surveys and
development of a cover type map. We will take baseline measurements of
key condition indices such as density, height, and percent cover.
Strategy 2: Develop an Integrated Pest Management Plan (IPMP), which
will provide a full range of potential and alternative mechanical, biological
and chemical control strategies. We will include a monitoring program as a
part of the plan, which will consist of plot sampling, estimates of cover, and
responses of wildlife and other plants. We will use the
IPMP in concert with habitat monitoring to assess
progress and the effectiveness of different techniques,
and identify additional problem species. We will
research alternative methods of controlling certain
species as appropriate, based on monitoring results.
Control strategies will be species specific and may
employ biological vectors, mechanical methods (hand
pulling), fire, or herbicides. We will use the least
intrusive, but most effective control practice. As
previously discussed, use of herbicides would require
action specific step down plans, and in some situations
proposed control methodologies may also require
wetland permitting review and approval.
Strategy 3: We will also participate in appropriate, experimental invasive
species control research programs. These programs must be reviewed and
approved by Service regional or national biological staff and the
Department of the Interior’s wildlife research arm, the Biological
Resources Division, now located within the U.S. Geologic Survey, before
any research is initiated.
Strategy 4: Control invasive and overabundant animal species using the
most effective means available. There are currently identified problems
related to overabundant or invasive animal species on the refuge. Beaver
have occasionally caused localized flooding of refuge trails and maintenance
roads and are raising water levels, which is affecting a well on the refuge.
Control of such situations includes manually clearing culverts, installing
grates on culverts and water-control structures, and installing beaver
deceivers in dams or on culverts. Devices range from a simple PVC pipe
inserted into dams to reduce water levels, to fencing constructed in a
semicircle around a culvert with drain pipes inserted through the fence. If
more serious threats to habitat, refuge facilities, adjacent property or
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