Although the Reserve contains some of the best examples of native Hudson River estuarine natural communities, historically these sites have been affected negatively by invasive plant species, altered hydrology, land use patterns, and dredging and filling activities associated with the construction of the federal navigation channel and railroad dikes. While many of these impacts are irreversible, there are opportunities for enhancing ecosystem function in the Reserve through habitat restoration. As a living laboratory, the Reserve serves as both a reference site and place to test innovative restoration strategies that advance restoration science and inform decision‐making. We leverage long‐term monitoring data to evaluate restoration success and develop models and tools to support restoration planning.
Restoration Projects
Marsh Resilience
Many of the Reserve’s habitats are vulnerable to the direct and indirect changes associated with rapid climate change, including accelerated sea level rise, more intense storms, more frequent surge, changing patterns of drought and rainfall, and increasing heat. Of major concern is whether the Reserve’s tidal wetlands will be able to keep up with or adapt to changing water levels, wave energies, and other factors. In order to inform resilience planning and management, we closely monitor changes in marsh surface elevation, accretion, erosion, vegetation, and hydrology. Based on these data, we implemented a pilot a shoreline stabilization project at Piermont Marsh in 2023 to enhance resilience by reducing marsh edge erosion and increasing sediment deposition.
2023 Pilot Shoreline Stabilization Project
In 2023, we completed the pilot shoreline stabilization project at Piermont Marsh to protect and enhance more than 300 feet of marsh edge. Oyster castles, made from a special blend of concrete and oyster shells, were placed parallel to the shoreline to function as sills. These low-profile structures were supplemented with coir logs made from coconut fibers and smooth cordgrass plantings to reduce erosion and trap sediment. The hybrid living shoreline was completed through a partnership with volunteers from the Rockland Conservation and Service Corps, the Student Conservation Association, NYS Parks, and the Village of Piermont. The project supports marsh resilience by reducing wave energy, promoting sediment accretion, protecting wildlife habitat, and augmenting the marsh’s ability to buffer the adjacent community from storms.
Gay's Point Side Channel
We began working with the New York State Thruway Authority (NYSTA) in 2013 to design and implement the restoration of a tidal side channel at Stockport Flats. The project is the first of its kind in the Hudson River estuary and restored a mosaic of shallow water, tidal wetland, and shoreline habitats.
Construction of the 1,200-foot-long by 100-foot-wide side channel was completed in 2017. The project involved the excavation and onsite reuse of approximately 20,000 cubic yards of historical dredge spoils and the installation of more than 5,000 native plant plugs and 600 live stakes. Since 2018, we have been monitoring key structural and functional indicators of ecosystem health. Continued monitoring at both project and reference sites will inform adaptive management, evaluate project success, and guide future restoration efforts.
Oyster Habitat
Once a common component of the lower Hudson River Estuary, eastern oysters have declined significantly since the 1700s due to overharvesting, loss of habitat, pollution, and disease. By creating complex three-dimensional reefs, oysters provide diverse habitat for hundreds of marine animals. Because they are filter feeders, they also help to improve water quality by removing particles and pollutants. The Reserve is working with partners to assess current oyster populations and restore healthy oyster beds and the many benefits they provide.
Artificial Reefs
In 2018, we worked with NYSTA, AKRF, Inc., the Hudson River Foundation, the Billion Oyster Project, and the University of New Hampshire to create more than five acres of oyster habitat at three sites near the new Governor Mario M. Cuomo Bridge. These sites were selected after a three-year pilot study on the performance of various artificial reef materials and locations for restoration in the Tappan Zee.
Nearly 900 concrete reef balls and more than 400 oyster shell gabions were placed at strategic locations along the river bottom. The Billion Oyster Project and New York Harbor School constructed the steel gabion structures and filled them with recycled oyster shells from restaurants. The reef balls and gabions provide habitat for a variety of estuarine fish and an ideal hard surface where oyster larvae can attach and grow. Although additional monitoring is needed to evaluate the long-term sustainability of the reef communities, successful early reef development has been observed at all three restoration sites.
Oyster Mapping
In 2025, DEC’s Hudson River Estuary Program partnered with NEIWPCC and Henningson, Durham & Richardson Architecture and Engineering, P.C. (HDR) to survey American oyster distribution, density, and suitable habitats in an approximately 10-mile section of the Hudson River Estuary from Piermont Pier, south to Yonkers, NY. The work fills a sampling gap from other surveys to the north and south to create a continuous map of presence/absence of oysters in the lower Hudson River Estuary and the conditions they prefer.
A total of 200 benthic samples were collected along 8 pre-determined transects that were established across the Hudson River in New York. From each sample, oysters were counted and measured, and sediment was characterized. Sonar data was also collected along each transect to identify bottom characteristics. Within the study area, oysters were found at 39 of the 200 sampling stations (19.5%). Oyster density was generally higher near the northern and southern portions of the study area. Density also appears to be higher near the edges of the navigation channel or in areas of topographic transition, at approximately 6 and 16 meters.
The data collected as part of this effort contributes to the Hudson River Estuary Program’s goal of improving 50 acres of oyster habitat by 2030. The information gathered will help guide efforts to locate and design future oyster restoration project in and around the estuary.
Invasive Species
An invasive species is an organism that causes ecological or economic harm in a new environment where it is not native. At the Reserve, we use the best available science and test innovative techniques to improve the efficacy of invasive species detection and management. Since management is most effective at the early stages of invasion, we actively monitor Reserve habitats to prevent the establishment of new populations of known or suspected invasive species. Established populations of invasive species are mapped and monitored to prioritize and inform management. If management is deemed feasible and necessary, we develop and implement site‐and species‐specific actions to protect rare species and exemplary natural communities.
Common Reed Management
In the recent decades, non-native common reed (Phragmites australis) has replaced much of the brackish tidal marsh community at Piermont Marsh, becoming the dominate vegetation. Native species including chairmaker’s bulrush, sturdy bulrush, narrow-leaved cattail, salt-meadow cordgrass, salt grass, rosemallow, saltmarsh fleabane, and seaside goldenrod still occur in small, isolated patches. In 2020, we began a pilot study to evaluate non-chemical Phragmites management methods and restore native habitat in the center of the marsh. The ongoing project is investigating the use of cutting and solarization (covering with black landscape fabric) to reduce Phragmites cover and allow for the expansion of remanent native plant populations. We are also testing the use of native seed collected from the marsh to speed up the recovery of native plant communities following Phragmites management.
Restoration Story Map
The National Estuarine Research Reserve System (NERRS) has published a Restoration Story Map that highlights lessons learned from restoration efforts nationwide. Stories related to marshes, dunes, uplands, living shorelines and oyster reefs are currently included and communicate the contribution of NERRS to restoration science. Moreover, the story map provides links to relevant data, as well as data analysis tools developed by NERRS and restoration-related funding opportunities.
As a living project, the story map will continue to expand as new stories, including those featuring additional habitats, are submitted. NERRS encourages restoration practitioners to visit the story map and explore collaborative restoration science opportunities with NERRS sites, like the Hudson River Reserve!
Restoration Plans
2013 Hudson River Estuary Habitat Restoration Plan
This plan identifies priority habitats vital to the health and resiliency of the estuary and actions for restoring them. The plan is a basis for coordinating funding, planning, research and implementation of resources toward a single, focused goal: The enduring health and well being of the Hudson River estuary, its inhabitants and the people of the Hudson River Valley and New York State.
2018 Hudson River Comprehensive Restoration Plan
The Hudson River CRP is intended to inform how the region responds to challenges, to propose attainable goals, provide reference to place-based opportunities, and recommends additional forums to catalyze and support collective action. The Hudson River CRP is meant to be an adaptively managed tool that is responsive to continued dialogue, realized future conditions, new knowledge and experiences.