Avalon’s dune system is a natural beach ecosystem consisting of a foredune, primary, secondary and tertiary dunes. The dune system produces variable salt exposure to the plants in the dunes because of the different landforms that develop. Dunes are host to many plant and animal species. The most salt tolerant species live along the back beach and the foredune where salt spray is most frequent. As far back as the secondary or tertiary dune, freshwater springs and vernal ponds may be found. This creates opportunities for a wider variety of animals including frogs, toads and salamanders. The varying salt exposure of the dune structure allows for multiple stages of plant development and of diverse ecosystems within a confined area. This development, which often takes hundreds of years, can be seen by walking just a few hundred feet!