Invasive plants on the refuge, including phragmites, perennial pepperweed, purple loosestrife, bush honeysuckle, and oriental bittersweet, out-compete our native plants and, in turn, hurt the animals that rely on our native plants for food and shelter. The refuge’s goal is to remove the non-native plants and protect the biodiversity of our habitats.
The refuge employs several techniques to control invasives including hand pulling and cutting, mowing, herbicides, and biological control. The refuge relies heavily on volunteers to control invasives. Not only do they provide help in removing invasives on the refuge, they are also able to take their knowledge and experience off the refuge to identify and control invasives in other places. To learn about the Great Marsh Pepperweed Eradication Project and/or to inquire about how you can help, please click here (pdf).
The refuge is home to three human-made freshwater marshes, or impoundments. Impoundment water levels are lowered to expose mud flat to provide for feeding and resting areas during shorebird migration, and raised again during waterfowl migration. This technique also benefits herons, river otter, and other wildlife by concentrating fish and other prey in shallow pools.
Piping plovers and least terns – the former being federally threatened – nest on the beaches of Plum Island. As the lead federal agency involved in the recovery of endangered species, the US Fish and Wildlife Service has a responsibility to manage and protect these species.
The refuge closes most of the beach during nesting season to provide undisturbed habitat for these birds. Wire cages called exclosures are often placed around plover nests to protect them from fox, coyote and other predators. These cages allow the plover to move in and out freely but prevent predators from disturbing the nest. The refuge also takes responsibility for protecting and monitoring plovers and terns on the northern town-administered and southern state-owned beaches on Plum Island.
Saltmarsh Sparrow Study
The refuge is conducting long term monitoring and research of saltmarsh sparrows and the role mercury may plays in their life cycle and reproduction. Saltmarsh sparrows rely on high quality salt marshes between Maine and Delaware for their summer habitat. The refuge is positioned in the center of their summer range, providing excellent protected salt marsh habitat for the sparrows.
In the summer months, sparrow nests are searched for out in the salt marsh and monitored until the eggs hatch. We collect blood samples and insects on which the birds may forage to test for the presence of mercury. We hope to learn more about the habits of the saltmarsh sparrow, whether mercury is present in the ecosystem, and how mercury affects the sparrows.
Salt Marsh Integrity Index
Along with other refuges on the east coast, Parker River National Wildlife Refuge is participating in a study to determine the characteristics of a healthy salt marsh. Salt marshes are highly productive ecosystems and serve as nurseries for fish and breeding habitat for many birds and ducks. In the current study, we sample fish and invertebrates in ditches, creeks and pannes; record vegetation characteristics; and measure water quality and salinity. Soon these rapid assessment techniques will be adopted nation-wide.
Shrub Restoration and Migratory Song Birds
One key habitat on the refuge is the maritime forest, a dense self-sustaining shrubland. The shrubs provide shelter and food for migratory song birds. As songbirds head south in the fall, they need lots of nutrients to complete their long migration. The refuge is collaborating with other refuges to test methods which will improve the shrub habitat for birds, and our goal is to create very dense shrubs that provide cover and high quality berries to fuel the birds during migration.
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With the 2015 plover breeding season now a fond memory, the refuge's entire Atlantic Ocean beach is now publicly accessible.