Service releases Final Habitat Management Plan and Environmental Assessment for Parker River and Thacher Island National Wildlife Refuges

Finding of No Significant Impact and Selected Alternative

After reviewing comments received and further consultation with experts and partner organizations, the U.S. Fish and Wildlife Service made a Finding of No Significant Impact (FONSI) in implementing the proposed alternative outlined in the draft Habitat Management Plan (HMP) and Fire Management Plan (FMP) for Parker River and Thacher Island National Wildlife Refuges.  Refuge staff updated the final Habitat Management Plan and the Fire Management Plan to provide more detail and clarification and added more in-depth analysis to the Environmental Assessment (EA)  to address questions about socioeconomic impacts and impacts of prescribed fire; as well as impacts to bird use and bird watching opportunities.     These final documents are linked below.  Hard copies of these documents with changes highlighted are available at the Parker River National Wildlife Refuge Visitor Center at 6 Plum Island Turnpike, Newburyport, MA. 

Under the selected alternative, the Service will implement strategic, adaptive approaches that maintain and restore the ability and resiliency of wildlife and habitats to adapt to climate change climate change
Climate change includes both global warming driven by human-induced emissions of greenhouse gases and the resulting large-scale shifts in weather patterns. Though there have been previous periods of climatic change, since the mid-20th century humans have had an unprecedented impact on Earth's climate system and caused change on a global scale.

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and other stressors.  Prescribed fire will be incorporated as a tool to meet habitat goals.  Tidal restoration to the three refuge impoundments will be phased over the next 15 years, starting with Stage Island.  Extensive monitoring and adaptive learning of impoundment vulnerability and transition of Stage Island post-tidal restoration will inform and refine the decision regarding North Pool and Bill Forward Pool.  

Where to Read the Final Documents

A virtual copy of the finalized documents can be read online at:

Hard copies are also available to read at the refuge visitor center located at 6 Plum Island Turnpike, Newburyport, MA 01950

Public Comments Received During Comment Period

Many individuals attended the Information Sessions and submitted comments during the public comment period from September 28 to October 28 of 2023.  In addition to comments provided at the information sessions, we received written comments from 145 people, with a large portion of comments strongly opposed to breaching the impoundments.  

It is evident that everyone who commented deeply cares about the Refuge and its wildlife and habitats and wishes to see the best management decision.  Refuge staff appreciate those who took the time to add thoughtful perspectives and additional information.

Summary of Comments and Response

The U.S. Fish and Wildlife Service reviewed, synthesized, and considered all comments received, and consulted additional experts and partners as needed.  A detailed summary of comments and responses is included in Appendix A of the final Environmental Assessment.  Key comments and responses are excerpted as follows:  

What is the timeline for decommissioning the impoundments? 

The timing for implementing tidal restoration to the impoundments will depend on many factors, including securing funding and necessary permits, staffing capacity, and changing environmental conditions and climate predictions. Refuge staff aims to initiate tidal restoration to the Stage Island Impoundment by 2027.   

The final plan has a goal of restoring tidal flow to Bill Forward and North Pool Impoundment by 2035, but the exact timing may be adjusted based on results of the Stage Island project, the vulnerability of the other two impoundments and relative elevation difference between the impoundments and adjacent salt marsh salt marsh
Salt marshes are found in tidal areas near the coast, where freshwater mixes with saltwater.

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Why are you restoring the impoundments and what would success look like? 

The three Refuge impoundments have been managed for nesting, feeding and resting habitat for waterfowl since the 1950s,

 and for migrating shorebirds and nesting marsh and wading birds in the last 20 years, providing exceptional opportunities for wildlife observation. However, the impoundments have also been subsiding, the infrastructure to maintain them is aging, and the freshwater wetlands are being overtaken by invasive species invasive species
An invasive species is any plant or animal that has spread or been introduced into a new area where they are, or could, cause harm to the environment, economy, or human, animal, or plant health. Their unwelcome presence can destroy ecosystems and cost millions of dollars.

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such as
Phragmites sp. Further, increased storm frequency and intensity makes the dikes more vulnerable to breaching. An unplanned breach would lead to further subsidence, anoxic dead zones, potential erosion of the Refuge Road, and costly subsequent restoration. Through proactive restoration over the next 12+ years, the Service will create conditions to allow impounded areas to adapt to climate change, keep up with sea level rise, reduce invasive plants, and benefit fish, shorebirds, and waterfowl species.

Final design and permitting for the Stage Island Impoundment will provide exact details on how the project will be implemented.  Successful grant funding will determine exact timing of when restoration will occur.  Extensive monitoring will ensure that the project is progressing as anticipated and adaptive management will be implemented to address any issues. 

A successful project for Stage Island would be a tidal regime where the flooding and ebbing tides are in equilibrium. Visually, the former impoundment would have a mosaic of mudflats and vegetated marsh (Spartina and other saltmarsh species). The area is expected to have extensive mudflats immediately after tidal flow is restored. As much as possible, staff will allow flooding tides to form tidal channels inside the impoundments, and deposit sediment on the marsh surface; thus, raising marsh elevation. Any area that revegetates in Spartina alterniflora will trap additional sediment and add biomass to marsh accretion (at rate of 6-10 mm per year or higher). The Stage Island Impoundment is currently losing elevation at rate of 2-3 mm per year. 

Extensive monitoring will provide detailed information regarding timing and extent of anticipated transition after tidal restoration, which will further refine decisions regarding the other two impoundments.  The observation tower and platform around Stage Island will provide good vantage points to observe both habitat and wildlife throughout the transition period.  

Can you leave one impoundment (Bill Forward Pool) in place?  

Staff considered this request received during the comment period, and decided that it would be irresponsible to commit to no action with the risk of catastrophic failure increasing each year.  However, the timing of implementation for Bill Forward and Stage Island Pools can and will be adjusted based on future monitoring data.  Refuge staff believe that both bird use and wildlife viewing opportunities will be sustained or expanded in the restored estuaries.  The monitoring of Stage Island project will inform this in the next 10 years.  Staff welcomes collaboration and assistance from the birding community to help us document changes in wildlife use post tidal restoration.  

Concerns regarding loss of habitat for bird use and decrease in wildlife viewing experience  

While many people expressed concerns about perceived loss of habitat to shorebirds, waterfowl, marsh and wading birds and roosting tree swallows, the Service anticipates many of these birds to continue using the estuary habitat post tidal restoration.  Further, we believe that tidal restoration is the only way to ensure the long-term availability of these areas to support wildlife use.  

Some birds, such as shorebirds and waterfowl, would continue to use the restored salt marsh and tidal flats, and will benefit from the abundant invertebrates provided by the flooding and ebbing tides.  The prior Salt Pannes restoration is a good example of how the impoundment may support shorebirds and waterfowl in the initial years post-breaching.  As the former impoundment gains elevation and revegetates, waterfowl use will increase, as will use by some secretive marsh birds, like Clapper Rail, American Bittern, King Rail and Marsh Wren. These areas may also support the Federally listed Black Rail in future years as species shift northward.   However, birdwatchers may not see nesting Least Bitterns and Virginia Rail, which currently breed in the North Pool, and use freshwater marshes.

Every August, Parker River NWR receives tens to hundreds of thousands of tree swallows that congregate prior to migration.

  This annual phenomenon will continue as the tree swallows are attracted to the Refuge by the abundant berries and insects in the maritime shrub and forest habitat.  A significant portion of the swallows currently roost in the North Pool vegetation (mainly Phragmites and cattail).  This will remain unchanged for 10+ years.  When North Pool is breached, tree swallows will shift to roosting in other areas, including the shrubs as they currently do; or even tall Spartina alterniflora that may comprise a significant portion of a restored Stage Island Estuary.  

Many people expressed concerns over the loss of wildlife viewing opportunities with the proposed impoundment breaching.  Except where the breach needs to be cut to restore tidal flow, the impoundment dikes will remain and continue to provide elevated viewing opportunities.  Bird use will shift slightly and continue to evolve as the estuary recovers following restoration.  The restored estuary will continue to provide good wildlife viewing opportunities, with a shifting variety of species and guilds as the habitat evolves 5-10 years post restoration.  

What is the true risk of catastrophic failure, and can Refuge improve the dike to reduce risk?  What’s the risk to Hellcat swamp? 

Although the dikes have held for 70 years, they are increasingly vulnerable to future storms.  Numerous unprecedented storms in the past decade have demonstrated that historical observations are no longer good predictors of future conditions.  The consensus among coastal geomorphologists (scientists that study the movement of landforms in response to storm and wave action) and salt marsh ecologists is that the vulnerability of the impoundments is tied to the width of the salt marsh adjacent to the dikes. As the salt marsh gets narrower, that protection decreases exponentially. The erosion of marsh at the base of the dike at the main creek channel is also a factor in dike vulnerability.  Simultaneously, increasing storm intensity increases the chance that a storm overtops the dike with each passing year.  

Raising the dike would temporarily stave off risk of breach for some storms but will not ensure the long-term viability of the impoundment.  Delaying tidal restoration will also increase project cost and reduce the probability of success for future options. Refuge staff is unlikely to obtain funding for a project that delays restoration of ecological integrity and function on a national wildlife refuge national wildlife refuge
A national wildlife refuge is typically a contiguous area of land and water managed by the U.S. Fish and Wildlife Service  for the conservation and, where appropriate, restoration of fish, wildlife and plant resources and their habitats for the benefit of present and future generations of Americans.

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Hydrodynamic models based on 2016 data indicate that the Hellcat Forest will not be affected by restoring tidal flow of the North Pool. However, increased inundation from sea-level rise (SLR) and marsh migration may affect this area. As this action is at least 10 years out, Refuge staff will gather more updated field data to predict these impacts when design of the project is being finalized. To address these concerns, the following strategies were added under the Impoundment (p129) and Maritime Shrub and Forest (p119) Objectives in Chapter 5:  

  • As part of modeling and final design for decommissioning of North Pool, explore vulnerability of Hellcat Forest to dieback with tidal restoration. Explore options to reduce impacts to Hellcat Forest both immediately post tidal restoration and under future SLR scenarios. 

Is breaching the impoundment counter to the Refuge’s mission, or its mandate to manage for threatened or endangered species and biodiversity?  

The U.S. Fish and Wildlife Service is the primary agency responsible for conserving migratory birds in the United States, and has worked with partners to develop a flyway approach to bird conservation.  Through the Joint Ventures, bird conservation strategies are developed and regularly updated at various geographic scales that preserves and enhance all bird populations in perpetuity (Bird Conservation Regions).  In general, these strategies seek to focus management efforts on species where they are most abundant; thus increasing effectiveness of conservation strategies.   The national and regional strategies are stepped down to the network of over 500 refuges and disseminated to partner organizations.  For Parker River NWR (BCR 30), the highest priority bird species are black ducks and salt marsh sparrows, as well as shorebirds, waterfowl, and songbirds that use shrub habitat.  Marsh and wading birds that would lose freshwater breeding habitat with the implementation of the plan (Virginia and Sora Rail, Least Bitterns, Pied-billed Grebes, and American coots) are common nationally and globally with populations stable or increasing.  American Bittern and Common Gallinule are species of Least Concern, with small declines in population. 

In the context of rapidly changing climate conditions, restoring functioning habitats and healthy and robust wildlife populations will ensure that both wildlife and habitats can adapt and change to future stressors.  The final HMP and FMP restores the ecological integrity and function of Plum Island’s habitat to ensure that they will be resilient and provide habitat for wildlife for the next 100 years and beyond.