Across the Intracoastal Waterway, Jupiter Island was part of an ancient offshore sand bar that became exposed when sea level dropped. Protected from salt spray yet close enough to the ocean to receive its warming effects, the island has vegetation that is mostly tropical in nature. Such areas are called coastal beach hammocks and include trees such as Gumbo-Limbo, Stopper, and poisonwood. At one time, many islands in South Florida had beach hammocks, but extensive development destroyed most of them.