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<br />modification, and competition from nonnative fish are probably factors in their low populations in the <br />San Juan. Olson (1962) attributed low numbers to changes in water temperatures below Navajo Dam <br />and due to early efforts to remove nongame fish from the river. <br /> <br />The more natural hydrograph downstream from Farmington may benefit these species by reducing <br />nonnative fish that compete and by providing more natural habitat conditions. Upstream from <br />Farmington, adverse effects are possible because of reduced habitat associated with lower summer <br />flows and possibly by water quality declines; however, the fish is very uncommon in this area. <br /> <br />New Mexico silversoot and San Juan checkersoot butterflies <br /> <br />These insect species are native species with limited distribution. Populations are affected by habitat <br />losses and in some cases collection. The proposed action should not affect these species, although it <br />would provide a more natural river and floodplain condition which may benefit them. <br /> <br />San Juan tiger beetle <br /> <br />Tiger beetles are common but some species have limited distribution. Habitat includes sandy areas, <br />including riparian areas. As a native species, the San Juan tiger beetle would be expected to benefit <br />from a more natural riparian area; the proposed plan should have either a neutral or beneficial effect. <br /> <br />Gunnison sage grOUSe <br /> <br />The Gunnison sage grouse currently occurs in eight isolated populations in western Colorado and <br />southeastern Utah. The species has been in decline, presumably due to habitat loss and fragmentation. <br />Habitat includes large expanses of sagebrush with a diversity of grasses and forbs and healthy riparian <br />areas. Existing or potential habitat of this species would not be affected by the proposed reoperation of <br />Navajo Reservoir. <br /> <br />Other Species of Concern <br /> <br />The Navajo Nation provided a list of species of special concern that included several of the species <br />discussed above, but contained the following additional species: <br /> <br />Golden eagle <br /> <br />The golden eagle uses a variety of habitats in the San Juan basin including the San Juan River corridor. <br />Nesting occurs on cliffs or large trees. Primary foods include small manImals and carrion although <br />birds and fish can be included. Habitat used by these birds should not be adversely affected by any <br />project alternatives. <br /> <br />25 <br />