(Trifolium bolanderi). Although Category 2 was abolished in 1996, species of concern refers to those species that might be declining or be in need of concentrated conservation actions to prevent decline. Therefore, these six species continue to be evaluated and managed by the National Park Service. Four state-listed rare plant species are considered restricted and limited throughout all or a significant portion of their range, and may represent disjunct populations at the extreme end of their range: Yosemite onion (Allium yosemitense), Tompkin's sedge (Carex tompkinsii), Congdon's woolly sunflower (Eriophyllum congdonii), and Congdon's lewisia (Lewisia congdonii). Endangered or threatened species of animals that occur in the Sierra Nevada include: Sierra Nevada bighorn sheep (Ovis canadensis sierrae), endangered (2000) California condor (Gymnogyps californianus), endangered (1967) Southwestern willow flycatcher (Empidonax traillii extimus), endangered (1995) Paiute cutthroat trout (Oncorhynchus clarki seleniris), threatened (1975) Lahontan cutthroat trout (Oncorhynchus clarki henshawi), threatened (1975) Owens Tui chub (Gila bicolor snyderi), endangered (1985) Wetlands Wetlands in the Sierra Nevada occur in valley bottoms throughout the range, and are often hydrologically linked to nearby lakes and rivers through seasonal flooding and groundwater movement. Meadow habitats, distributed at elevations from , are generally wetlands, as are the riparian habitats found on the banks of numerous streams and rivers. The Sierra contains three major types of wetland: Riverine, Lacustrine, and Palustrine Each of these types of wetlands varies in geographic distribution, duration of saturation, vegetation community, and overall ecosystem function. All three types of wetlands provide rich habitat for plant and animal species, delay and store seasonal floodwaters, minimize downstream erosion, and improve water quality. Riverine wetlands are found within river and stream channels and are strongly influenced by seasonal runoff patterns. When inundated, riverine wetlands provide habitat for water-tolerant plants such as willows, and aquatic animals such as tadpoles and immature fish. Lacustrine wetlands generally occur on river floodplains and along lakeshores and are influenced by seasonal variations in groundwater levels. These wetlands are rare in the mountain range, but support an abundance of warm-water loving plant and animal species. Palustrine wetlands are typically distinguished from riverine and lacustrine systems by the presence of very dense covers of trees, shrubs, or emergent plants. This wetland type includes wet meadows, densely vegetated riparian habitats, and shallow ponds. They provide cover and forage for wildlife traveling between upland and aquatic habitats. Since the 1970s the United States has made substantial progress toward