Resource Management

Maritime forest boardwalk - Matt Poole/USFWS.

Beach Management

 

Piping plovers (federally threatened) and least terns nest on Plum Island’s beaches. These species are vulnerable to disturbance, so the Refuge closes most of the beach during the nesting season. To reduce predation, we sometimes place wire cages called exclosures around plover nests. Exclosures allow plovers to move in and out freely, but they protect the nests from predators like crows and coyotes. We also monitor plovers to determine the number of nesting pairs and measure productivity (the number of chicks that learn to fly).

 

In the fall, piping plovers and other migrating shorebirds use Refuge beaches and salt marshes to rest and feed. Many of these species travel thousands of miles during each migration (from the Arctic to South America). While the beaches are open to the public during much of the fall migration, we encourage visitors to give shorebirds a wide berth. By allowing shorebirds to rest and feed without disturbance, we improve their chances of survival.

 

 

Salt Marsh Restoration

 

Historically, humans built ditches and embankments throughout salt marshes to improve salt marsh hay farming and control mosquitos. However, salt marshes now flood more often due to sea level rise and climate change. Historic man-made ditches and embankments compound the issue by holding water on the marsh surface, killing marsh plants. By removing some ditches and embankments, we can drain excess water, allow plants to regrow, and increase overall marsh resilience. In collaboration with other partners, we tested several successful restoration techniques on the Refuge. If you are interested in learning more about these techniques, please contact Nancy Pau at nancy_pau@fws.gov.

 

Salt marsh restoration also helps conserve species like saltmarsh sparrows, which nest exclusively in salt marshes. In collaboration with other partners, we are conducting long-term monitoring and research to detect trends in sparrow populations and determine whether marsh restoration benefits sparrows on the Refuge.

 

 

Invasive Species Management

 

Native plants provide food and shelter to wildlife, but invasive plants sometimes outcompete them. When possible, we remove invasive plants to protect the biodiversity and resilience of Refuge habitats. We focus removal efforts on newly-detected invasive species and those in sensitive habitats, like salt marshes. We control invasive plants using hand pulling and cutting, mowing, herbicides, and biological control.

 

Volunteers also help control invasive plants, especially through the Great Marsh Pepperweed Control Project. Perennial pepperweed, an invasive plant in salt marshes, reduces habitat quality and resilience. The Refuge and Mass Audubon staff have been working with volunteers and partners to eradicate and contain this invasive plant  since 2006. Long-term removal efforts have successfully reduced or eliminated it in many places throughout the region. If you are interested in volunteering for the Great Marsh Pepperweed Control Project, please contact Luke Stuntz at luke_stuntz@fws.gov.

 

 

Impoundment Management

 

The Refuge has three impoundments, which are man-made freshwater or brackish (slightly salty) wetlands. The Refuge built the impoundments in the 1950s to create nesting habitat for waterfowl (ducks and geese) but subsequently found that they did not serve this purpose. Rather, most waterfowl nest in other regions of North America. However, the impoundments still provide habitat for various wading birds, shorebirds, and waterfowl during their breeding, migration, and wintering periods. Currently, we lower impoundment water levels to expose mudflats for feeding and resting shorebirds in late summer, and we raise water levels during waterfowl migration in the fall. However, we are also balancing management decisions with the need to foster climate resilience, as the impoundments cannot naturally adapt to climate change and sea level rise.

 

 

Grassland Management

 

Several old fields were farmed intensively before they became part of the Refuge. The Refuge transitioned these farm fields into grasslands in the 1960s. For decades, the Refuge mowed the fields annually to prevent shrubs from growing. However, we have since stopped mowing several of the old fields, allowing them to return to their natural state as shrublands. Shrublands require less management and are more valuable to a variety of wildlife, including many birds and migrating bats. We continue to mow several other fields annually to benefit grassland birds and pollinators.

 

Inventory, Monitoring, and Research

 

Staff conduct various inventory and monitoring surveys of the Refuge’s plants, wildlife, and habitats.  While refuges are not strictly research organizations, staff also conduct various research projects to better understand emergent threats or to better inform management choices.  Research focus is determined by need.  Past examples include:

 

  • Bioaccumulation of mercury in estuary and impact to salt marsh sparrows and common eiders
  • Population dynamics and migratory patterns of saltmarsh sparrows, shorebirds, and bats
  • Changes in beach geomorphology in relation to climate impacts
  • Effectiveness of various invasive plant control methods
  • Effectiveness of restoring grasslands to native shrub communities
  • Bird and vegetation response to different water levels and vegetation management in Impoundments
  • Hydrodynamics modeling of salt marsh and impoundment habitats in response to sea level rise
  • Marsh change monitoring and effectiveness of various restoration techniques.