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<br />Arizona Game and Fish Department
<br />Draft EA: Kanab Ambersnail
<br />
<br />June 1998
<br />Page 2
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<br />translocation is to a maximum of three other sites in Grand Canyon in August 1998, during the
<br />reproductive period for KAS, Supplementation of the transplants with additional individuals on 2-3
<br />successive occasions will be necessary, The number of additional KASs to be transferred will depend
<br />on the outcome of the first effort, If a founder population appears to establish, supplementation will
<br />be with 10 individuals to help ensure the genetic diversity of the VP population is contained in the
<br />new population. If it appears the first effort was unsuccessful, larger numbers of KASs, equal to or
<br />greater than the number originally transferred, will need to be translocated,
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<br />Determination of success will be accomplished during monitoring at the release sites, To maintain
<br />consistency in data collection, we will be using the same methods previously used for monitoring the
<br />KAS population and habitat of VP. These methods require topographical mapping of vegetation at
<br />KAS establislunent sites to estimate baseline habitat area, seasonal change in habitat area, and future
<br />population estimates,
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<br />B, BACKGROUND
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<br />Status. In 1992, KAS was federally listed as endangered by the V,S, Fish and Wildlife Service
<br />(USFWS 1992), AGFD also recognizes KAS in its draft 1996 Wildlife of Special Concern in
<br />Arizona (AGFD in prep), Specific threats to KAS involve loss and/or adverse modification to
<br />wetland habitat which is scarce in the southwestern United States (USFWS 1995),
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<br />Cu"ent Distribution. Only two populations of the KAS are known to currently exist in the American
<br />Southwest; a third is presumed to have been extirpated in the last decade, One of the extant
<br />populations is found in southeastern Utah, on a privately-owned wet meadow dominated by cattails
<br />and sedges, The other population of this rare landsnail was discovered in 1991, at Vaseys Paradise
<br />(VP) in Grand Canyon National Park (Blinn et al 1992; Spamer and Bogan 1993). Located 46,8
<br />miles (75.3 Ian) downstream of Glen Canyon Dam, this site has a large, perennial spring with
<br />abundant poison ivy, crimson monkeyflower, and watercress,
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<br />Both populations are ~graphica1ly isolated (92,9 Ian distant), and believed to be relict from the Late
<br />Pleistocene glaciation, when wetland habitat was more abundant (Spamer 1993; Spamer and Bogan
<br />1993; Stevens et al, 1997b), Although the fossil record for Oxyloma is scarce, fossil shells have been
<br />found in the Grand Gulch area of southeastern Utah (Kerns 1993) and San Pedro Valley of Arizona
<br />(Bequaen and Miner 1973), Desertification of the American Southwest over the last 10,000 years
<br />has leduced the number and size of available habitats that could sustain KAS populations, The Grand
<br />Canyon region is believed to be the most recent historical range ofKAS,
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<br />Habitat Requirements. j(llnllh 21JlberSAails, like other succineid snails, are restricted to perennially
<br />wet soil surfaces and del:&)Iia& p\aDt "litter of springs and seep-fed marshes near sandstone or
<br />limestone cliffs (USFWS 1995), A linl!tin8 factor in their distribution may be the presence of cattails,
<br />monkeyflower, ~atercress, which ~ed as the primary vegetation for KAS habitat (Stevens
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