Reaching forty kilometres into Lake Erie, Long Point in Ontario, is the world's longest freshwater sand spit. How the Point's endless beaches endure as a natural oasis, here in Canada's most densely populated region, is a feat that involves more than just your typical environmentalists.  This is a story of hunters, farmers, foresters, birders, biologists, and just about everyone else in the Long Point Biosphere Reserve - who have learnt from conservation pioneers how to cultivate biodiversity, culture, and an economy, on a foundation of sand.  Now, at almost 30% natural cover, it's hard to believe that at one time, thousands of acres here were devoid of vegetation - a desert in the lush Canadian south.