The Challenge
Saltmarsh sparrow populations have been declining by nine percent annually since the early 1990s, resulting in the species being listed as Special Concern under the Massachusetts Endangered Species Act (MESA) in 2020 and currently being considered for federal listing under the United States Endangered Species Act. The decline in this species is thought to be due to a combination of salt marsh subsidence and the increased frequency of storm tides that result in nest failure. To address these concerns, the primary short-term strategy is to increase nest site availability at higher marsh elevations for a 20-to-30- year management period, which will allow the species to persist in the landscape while the natural accretion process restores marsh elevations relative to local sea levels. The nesting islands are created through beneficial reuse of material from associated runnel restoration projects. Managing for longer term accelerated accretion in the salt marsh platform would expand high quality habitats in high meadows within 15 to 20 years to increase productivity rates. Creation of nesting island refugia is a needed interim conservation measure to fill the gap between possible inundation from sea level rise and the building of salt marsh elevation and nesting habitat through ditch remediation, runnels, thin layer sediment placement, and tidal restriction removal projects.
Project Scope
The FY23 State Hazard Mitigation and Climate Adaptation Plan (SHMCAP) implementation grant was the third in a series leading to the completion of 5,293 acres (year 1:197 acres, year 2: 2,000 acres, year 3: 3,096 acres) of nature-based, salt marsh restoration preliminary designs. That is over 35% of the salt marsh acres in Great Marsh. If partner projects are included, then approximately 8,000 acres of Great Marsh have completed preliminary restoration designs which amounts to 53% of the entire salt marsh.
The two primary nature-based techniques utilized for the saltmarsh sparrow recovery strategy are ditch remediation and runnels, with creation of microtopography islands for nesting salt marsh sparrows. FY23 preliminary designs were completed in Newbury, Rowley, Ipswich, and Salisbury to coordinate with and complement FY21 and FY22 SHMCAP preliminary design grants. The restoration designs are forward-looking since consideration was given on how plans would complement other nature-based and restriction removal projects that have been completed or are near the implementation phase. The plans can be integrated with tidal restriction removal projects for holistic restoration. These preliminary designs provide the jump-start Great Marsh land managers need to implement restoration projects at a landscape scale.
Ditch remediation and runnel locations are identified at the tide shed level (like watersheds) within the salt marsh platform to correct over 300 years of agriculture infrastructure, as well as mosquito ditching, that is now causing damage to the salt marsh as sea level rises. The detailed maps show the different layers of design work and include aerial photographs depicting ancient agricultural features and mosquito ditching. Consistency in the design work over the last three years was maintained by using the same contractor, Northeast Wetland Restoration. This contractor’s staff of experts has increased over the last three years of SHMCAP grants, which increases the state’s capacity to implement restoration projects with skilled professionals.
Preliminary designs from this project provide the basis for restoring thousands of acres of salt marsh in Great Marsh (15,000 acres total) through a process of reestablishing single channel hydrology within each tide shed. Through proper placement of ditch remediation and runnels, the salt marsh platform will be able to build elevation and revegetate with salt marsh grasses increasing its ability to adapt to sea level rise and continue to provide important ecosystem functions. A resilient salt marsh is based on its ability to grow in elevation as sea level rises. As these preliminary designs are implemented throughout Great Marsh, historic agriculture embankments, haul roads, trunks, and ditching will be identified and modified to slow, or halt oxidation and inundation of salt marsh vegetation, and stop mega pool formation. The development of preliminary restoration design plans is the most important building block to implementing nature-based techniques at size and time scales that can significantly reduce the long-term risk of losing salt marsh habitat. Metrics that will be employed to measure success include number of acres restored annually, the amount of vegetation within ditch remediation sites, mega pools and controls, elevation changes in the marsh platform, and salt marsh sparrow reproduction on microtopography nesting islands.
Results
As a result of this project, Standard Operating Procedures (SOPs) have been developed for assessing salt marshes for ancient agricultural and mosquito ditch features, as well as the methods used to create single channel hydrology with placement of runnels, locations for ditch remediation, and where nesting islands will be created. SOPs will continue to be refined through permitting. MassWildlife and partners quickly learned that we need to build institutional capacity to ensure the consistent implementation and monitoring of these nature-based projects. As a valuable offshoot, MassWildlife, The Trustees, MA Audubon Society and USFWS are collectively growing and training a team of biologists and technicians to implement an efficient and effective monitoring system (vegetation, hydrology, sedimentation, saltmarsh sparrows) connected to an adaptive management strategy protective of the salt marsh.
SHMCAP I and II preliminary designs were much improved in SHMCAP III to include an expanded micro-runnel design reaching out laterally from tidal ditches to connect lower elevation salt marsh to the primary channel flow. This change promotes increase growth in salt marsh elevation on a shorter time scale.
SHMCAP preliminary designs are already being used by USFWS, MA Audubon Society, and The Trustees in nature-based salt marsh implementation projects in Great Marsh. Recent MassWildlife funding from the National Coastal Resiliency Fund will move 3,000 acres of SHMCAP preliminary designs through the permitting process over the next three years. Once permitting is completed, those 3,000 acres will be available for the implementation phase. Inserted, is an education and outreach program currently in production by MA Audubon Society with input from MassWildlife. During the assessment phase of the SHMCAP grant the contractor reached out to large landowners, like the Town of Ipswich and Rowley, to make them aware of proposed work and obtain their approval to include their lands in design plans. They enthusiastically joined the project.
An essential outcome of the SHMCAP grants is that coastal scientists, ecologists, and wildlife biologists came together to develop an oversight team (SMARTeam – Salt Marsh Adaptation and Resiliency Team) to review nature-based designs for consistency using the best available science. The SMARTeam is also involved in developing efficient landscape-scale monitoring protocols. Furthermore, a coast-wide need was identified to train more SMARTeams so a broad set of coastal experts would be available to restore a significant portion of the over 40,000 acres of MA salt marshes. A 3-year Resilient Mass grant, starting in FY25, has been funded to begin building this workforce.
MassWildlife became aware through this process that long-term monitoring of thousands of acres of restoration projects would entail use of remote sensing technology and other targeted and rapid assessment methods. Towards that end, two MassWildlife Northeast District staff have completed drone certification and are supported by a MassWildlife UAS Committee. A FY25 Resilient Mass grant was awarded to develop and refine long-term monitoring protocols for these types of restoration projects.
An additional work force need was identified to assist with implementation and long-term monitoring of thousands of acres of salt marsh restoration projects over the next 30 years. A work-training program is in the nascent phase of development to bring in Environmental Justice, Tribal and local communities as the backbone of the technical work force for salt marsh platform projects, and other coastal restoration projects (e.g. eel grass, tidal restriction, thin layer placement, pepperweed, green crab).
Project Alignment with SHMCAP and ResilientMass Plan Priority Actions
This project aligns with Action Topic 4: Improve coastal wetland mapping, resilience planning, and restoration efforts, under 2023 ResilientMass Plan urgent priority impact: Coastal Wetland Degradation.
Further Action
In the future, MassWildlife intends to expand restoration plans on privately held salt marsh parcels, and to fill any gaps identified by partners. A Resilient Mass FY25 grant will fund an additional 2,000 acres of preliminary design to fill gaps. MassWildlife expects to learn much in the next few years of permitting and implementation of nature-based projects, and from results of on-going related research, which will be integrated into future grant applications.