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<br />OJ2:J84 <br /> <br />2 <br /> <br />and Marsh 1996). Native suckers breed in several tributaries. including the LCR. and like <br />humpback chub, their young are probably susceptible to thermal shock as they drift into the <br />mainstream. Neither native fish nor rainbow trout were detectably affected by the 1996 Test <br />Flow and their populations appear to be similar to the pre-1996 Test Flow condition. The <br />Glen Canyon reach supports a blue-ribbon rainbow trout fishery, of which as much as 70% <br />may be naturally produced. <br /> <br />Water flows and sediment affect terrestrial biological resources, such as wetland and <br />riparian soils, vegetation and fauna, including several species of concern. The Test Flood in <br />1996 buried pre-existing sandbar vegetation, homogenized riparian soil texture, and increased <br />groundwater and soil nutrient concentrations in 1996-1997. Slight gradients established under <br />constant flows may direct groundwater flow patterns. Wetland and riparian vegetation has <br />become established since 1963, and some was scoured by high flows. Sandbar ground cover <br />vegetation buried by the 1996 Test Flow has recovered little and the seed bank was reduced. <br />but previously established woody vegetation did not suffer dramatic mortality. The timing of <br />the 1996 Test Flow limited saltcedar seedling establishment, but constant high flows in latter <br />1996 through 1997 allowed more establishment in 1997. These impacts were observed <br />throughout National Park Service lands and on the Hualapai Reservation below Mile 250. <br /> <br />Terrestrial species of concern are being monitored to determine long-term population <br />trends and responses to adaptive management floods. The Kanab ambersnail exists at Vaseys <br />Paradise in native and non-native herbaceous vegetation. The 1996 Test Flow reduced its <br />habitat and population size and recovery in the flood zone has been limited by slow <br />reestablishment of host plant vegetation. Endangered southwestern willow flycatcher wetland <br />feeding habitat was reduced by the 1996 Test Flow, but no direct impacts on nesting trees or <br />on the birds themselves were detected. The -9 Mile Spring populations of northern leopard <br />frog and Niobrara ambersnail survived the 1996 Test Flow and exist in good abundance in <br />1997. No 1996 Test Flow impacts on endangered peregrine falcons or threatened bald eagle <br />were discernable. and 1997 populations appear reasonably robust. <br /> <br />The short-term and long-term impacts of the currently implemented Preferred <br />Alternative, coupled with planned floods. may include short and long-term changes in <br />populations of some species of concern and in some habitat types. as well as tradeoff's <br />between aquatic and terrestrial resource components. As such, future planned high flows in <br />this ecosystem are likely to continue to require consultation with the U.S. Fish and Wildlife <br />Service (USFWS). <br /> <br />Monitoring and mitigation was conducted at cultural resource locations. including <br />archaeological and ethnobotanical sites. that had the potential to be affected by the 1996 <br />experimental flow. Monitoring occurred at 36 archaeological sites and mitigation activities at <br />eight locations along the river corridor. Ethnobotanical resources were monitored at five <br />locations and at the Goodding willow at Granite Park. The overall findings of the cultural <br />resources studies done in conjunction with the 1996 Test Flow strongly suggest that it either <br /> <br />Final Draft - 12/12/97 - For AMWG Review <br />