They began by listing the various ecosystems they could safely assume existed on the island, such as old-growth forests, wetlands, or plains, based on soil types, rainfall, and so on. Because it was located at the intersection of geographic regions, Manhattan probably had not only spruce trees from the northern forests but also magnolias from the southern forests, migratory birds from nearby flyways, and even tropical fish from the Gulf Stream during summer. In all, they identified 55 different ecological communities. "It was an incredibly diverse place," Sanderson said. "If the island had stayed the way it was back then, it could have become a national park like Yosemite or Yellowstone."