crameri). The Oregon chub is also found in the Umpqua River and nearby basins. The lower Snake River also supports seven species of Pacific salmon and trout (Oncorhynchus). There are also high, often localized levels of mollusc endemism, especially in Hells Canyon and the basins of the Clearwater River, Salmon River, and middle Snake River. The mollusc richness extends into the lower Columbia River and tributaries such as the Deschutes River. Animals Aside from aquatic species, much of the Snake River watershed supports larger animals including numerous species of mammals, birds, amphibians, and reptiles. Especially in the headwaters and the other mountainous areas strewn throughout the watershed, the gray wolf, grizzly bear, wolverine, mountain lion and Canada lynx are common. It has been determined that there are 97 species of mammals in the upper part of the Snake River, upstream from the Henrys Fork confluence. Pronghorn and bighorn sheep are common in the area drained by the "lost streams of Idaho", several rivers and large creeks that flow south from the Rocky Mountains and disappear into the Snake River Aquifer. About 274 bird species, some endangered or threatened, use the Snake River watershed, including bald eagle, peregrine falcon, whooping crane, greater sage-grouse, and yellow-billed cuckoo. Barrow's goldeneye are a species of bird that occurs commonly along the lower section of the Snake River. Ten amphibian and twenty species of reptiles inhabit the upper Snake River's wetland and riparian zones. Several species of amphibians are common in the "lost streams" basin and the northeasternmost part of the Snake River watershed, including the inland tailed frog, northern leopard frog, western toad, Columbia spotted frog, long-toed salamander, spadefoot toad. However, in the lower and middle portions of the Snake River watershed, several native species have been severely impacted by agriculture practices and the resulting non-native species supported by them. Introduced birds include the gray partridge, ring-necked pheasant, and chukar. Other non-native species include the bullfrog, brown-headed cowbird, and European starling, attracted by the construction of cities and towns. Plants The Snake River watershed includes a diversity of vegetation zones both past and present. A majority of the watershed was once covered with shrub-steppe grassland, most common in the Snake River Plain and also the Columbia Plateau in southeastern Washington. Riparian zones, wetlands and marshes once occurred along the length of the Snake River and its tributaries. In higher elevations, conifer forests, of which