Location: Frelinghuysen township, Warren County and Green township, Sussex County
Acres protected: 714 acres
Established: 1990
Managed by: The Nature Conservancy
Why is This Land Special?
Johnsonburg Swamp Preserve protects a limestone forest and is considered one of the most important and species-rich natural areas in the state. Mud Pond, at the heart of the preserve, is a limestone wetland providing excellent habitat for rare plant species, along with waterfowl and other wildlife. The scenic limestone outcrops that overlook the pond to the west and north are the largest rock formations of their kind in the state. It is this limestone bedrock that produces the calcium-rich soil in which Johnsonburg's rare plants flourish. Examples include hoary willow (Salix candida), ebony sedge (Carex eburnea), leathery grape-fern (Botrychium multifidum), white-grained mountain rice grass (Oryzopsis asperifolia) and lesser bladderwort (Utricularia minor), which is found at only three other sites in New Jersey. This carnivorous plant produces yellow flowers and floats in the water, where it periodically extends the equivalent of a small trap door that sucks in insects that brush against it. Threatened wildlife that make their homes around Mud Pond include great blue herons (Ardea herodias), red-headed woodpeckers (Melanerpes erythocephalus), barred owls (Strix varia), red-shouldered hawks (Buteo lineatus), wood turtles (Clemmys insculpta) and longtail salamanders (Eurycea longicauda longicauda). Red-spotted newts (Notophthalmus viridescens), though not threatened, are commonly found in the moist forested areas of the preserve.
Samuel Green, a prominent surveyor, was the first European settler in the area in 1730. For the next two centuries, agriculture dominated the landscape. In recent decades, dairy farms dotted the rolling hills of the area, and the Erie-Lackawanna Railroad roared through Johnsonburg. In the 1970s the railroad closed. Today, the area is beginning to see an increase in housing development.