Over the past week New York marked the 400th anniversary of the Dutch arrival with a design festival on Governor's Island and the unveiling of a pavilion by Dutch architect Ben Van Berkel, among other commemorations.

The events were sprinkled with references to Mannahatta, or "island of many hills" as the 500 or so Lenape inhabitants called it. If the anniversary has a central image, it's the computer rendering of the unspoiled Manhattan landscape of 1609, with its rolling hills and salt marshes.

The image was drawn from the Mannahatta Project, a decade-long effort by Landscape ecologist Eric Sanderson to map the ecology of Manhattan in the hours before Henry Hudson arrived. An exhibition based on Sanderson's work and designed by Abbott Miller, Mannahatta/Manhattan: A Natural History of New York City, is on exhibition at the Museum of the City of New York until October 12 and Sanderson's informed imaginings of wild Manhattan is on the cover story of this month's National Geographic.

An early hint of Mannahatta nostalgia came last year at the Whitney Museum's Bienniale, where Fritz Haeg, an architect by training and artist by temperament, filled the museum courtyard with habitations for the bald eagle, bobcat, beaver and nine other creatures that Sanderson says would lived on the museum's Madison Avenue site 400 years ago.

The Lenape revival includes a garden Haeg created on the lawn of a public housing development in the Chelsea neighborhood of New York using only plants that the Lenape employed for food or medicine, a list that includes hazelnut, persimmon, milkweed and elderberry.

The planting is part of a four-year project called Edible Estates in which Haeg persuades homeowners to rip up their front lawn and create an edible garden. You might think of it as a home makeover show with a radical activist bent.

Last night Haeg threw a party for the publication of his book The Sundown Salon Unfolding Archive, a scrapbook of performances, stunts and happenings held at his geodesic dome in Los Angeles. For six years, the Sundown Salons were a gathering spot for the city's avant-garde, and Haeg has documented them on one 140-foot long accordion-fold paper with text on one side and photos on the other.