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<br />ABSTRACT <br /> <br />The 1996 and 1997 U.S Fish and Wildlife Service Biological Opinions on the operation of Glen <br />Canyon Dam stipulate the need to establish or discover a second population of the endangered Kanab <br />ambersnail (KAS~ Succineidae Oxyloma haydem kanahell!'ils Pilsbry, 1948) in Arizona before <br />additional BeadvHabitat-Buildin'-t Flows (BHBF) can occur BHBFs are controlled floods from Glen <br />Canyon Dam designed to redistribute sediments from the channel bottom to the river banks <br />Interagency ecological studies and monitoring of the KAS population at Vaseys Paradise, Grand <br />Canyon were conducted between 1994 and 1997, These studies have documented flood impacts to <br />the KAS population and its habitat during the first BHBF in 1996, and subsequent high flows in 1997 <br />Beginning in 1996, the Arizona Game and Fish Department (AGFD) surveyed and evaluated 74 <br />springs, seeps. and wetlands in Grand Canyon and northern Arizona for suitable KAS habitat; no <br />additional KAS populations were found Eleven sites in Grand Canyon National Park were identified <br />as optimum or more desirable in biological and em;ronmental conditions for establishing new KAS <br />populations Grand Canyon National Park and AGFD are jointly submitting this draft em-;ronmental <br />assessment i~ the p.:2.~ o~tablishin~ new KAS populati~ns_r~S'tlie preferrd:IaJt~mative, ""iJ <br />"',5SQmmenq;mtroducmg- V aseyS"Paraglse-'"~Ss:to"three"-sltes slmultaneously...to Increase -die <br />CPLo.b.abjli!y;of'_"estaoli'Shment.,su'ecess,.:.-Each site should have a minimum population of I 00 pre- <br />reproductive KASs (<5 mm in size) in residence prior to overwintering (by the end of October 1998), <br />Supplemental stocking of KASs in 1999 will be required to augment population size and provide <br />genetic variability Two scenarios for stocking new establishment sites are presented The preferred <br />alternative lists the following three sites for KAS establishment: "KeyHole Springs" (just dOv.71stream <br />of Saddle Canyon on river right). Upper Elves Chasm. and Lower Deer Creek Spring, Other site sets <br />are ranked in order of preference, No adverse effects to natural. cultural. socio-economic resources, <br />visitor use, or listed/special status species is anticipated with the establishment of additional KAS <br />populations Tribal and ,,;sitor access to these sites will nol be restricted The establishment of an <br />addilional wild KAS population \ViII satisfy Biological Opinion requirements and alleviate Glen <br />Canyon Dam operational constraints concerning KASs for future BHBFs, In addition, the <br />establishment of ncv.' populations will help to meet Recovery Plan downlisting objectives for KASs <br />