The property, which includes wetlands and forests, is part of 2,200-hectare freshwater wilderness in Hants County that the group wants to protect as well.
The larger section of Crown land has been proposed for protection in the province's protected areas plan.
The area is known for as a popular spot for canoeing, and it is home to a number of species at risk, including the wood turtle, rusty blackbird and olive-sided flycatcher.
Longtime Nature Trust volunteer Dusan Soudek purchased the property in 2010.
He and the Nature Trust signed a conservation easement agreement that will offer permanent protection for the land.