Rondeau is famous for its remarkably lush Carolinian forest vegetation and uncommon assortment of wildlife. Visitors to Rondeau can see sassafras, tulip trees, Carolina Wrens and Fowlers Toads -- all species usually found much further south. The showy orchis orchid is one of the rarest in Canada and one of 19 orchids flourishing here.

This phenomenally rich environment sustains 33 mammal species, including Canada's only marsupial -- the oppossum. Approximately 145 of the 341 bird species recorded in the park nest here, among them the endangered prothonotary warbler.

Beach dunes, pine-oak and beech-maple forest, open water, and marshes characterize the landscape of the park. Eroded from nearby bluffs, and shaped by the rising and ebbing of the lake over several thousand years, the sands at Rondeau lie in long parallel ridges interspersed with valley-like depressions called sloughs. The sloughs and marshes around the bay are home to many types of turtles, snakes, toads and frogs.