Expanses of salt water limit the movements of animals and plants, making islands ecologically distinct from the mainland. There tend to be fewer species on islands, and unusual food webs arising from the order in which species arrived from elsewhere (“assembly rules”). Unique species, and genetically distinct variations in species, are also characteristic of islands. There are more than 50 vegetated islands in the San Juan Archipelago ranging in size from a fraction of an acre, to several square miles with mountains and streams. Annual rainfall varies dramatically from 12 inches on the southern tips of Lopez and San Juan Islands, to 55 inches on Mount Constitution (Orcas Island). Surprisingly little biodiversity research has been carried out in the San Juan Islands, however. Kwiaht is conducting inventories to fill that gap, and helping public and private landowners identify and conserve sensitive species.