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<br />Arizona Game and Fish Department <br />Biological Evaluation: Kanab Ambersnail <br /> <br />July 1998 <br />Page 4 <br /> <br />spp. as the molluscan intermediate host. Interagency studies at vp <br />confirm that KAS is an intermediate host for L. cyanocittae. <br />However, KAS investigators have not observed this parasite <br />infecting other molluscan species at VP or other locations <br />throughout Grand Canyon. Likewise, we have not found any <br />literature on Catinella spp. (a common succineid in Grand Canyon) <br />being an intermediate host for the genus Leucochloridium. Although <br />contamination of this species is possible, it remains undocumented. <br />If this parasite is being distributed by passerine birds throughout <br />Grand Canyon and vicinity, it is likely that controlling <br />infestation at KAS establishment sites may be beyond our control. <br />Current research has not demonstrated positive or negative effects <br />of this parasite on the KAS life cycle, population dynamics, or <br />reproduction. Examination of parasitized KASs, collected by AGFD, <br />indicated that KASs are still capable of producing egg masses (J. <br />Sorensen, AGFD, pers. comrn.). Parasite infection of the KAS <br />population at VP is not widespread, and may have naturally evolved <br />with this population. <br /> <br />D. HABITAT REQUIREMENTS <br /> <br />KASs inhabit marshes watered by springs and seeps at the base of <br />sandstone or limestone cliffs (Clarke 1991, Spamer and Bogan 1993) . <br />They are restricted to perennially wet soil surfaces or shallow <br />standing water. Within moist areas, KASs are often found on dry <br />litter or under driftwood (pers. corom. J. Sorensen, AGFD 1998). No <br />KASs have been observed outside of moist areas or in other micro- <br />habitats commonly utilized by other land snails (Clarke 1991). <br /> <br />Primary vegetation is believed to be a limiting factor in KAS <br />distribution. Comparable habitats for KAS require the presence of <br />one or more types of primary vegetation: cardinal monkeyflower <br />(~mulus cardinalis), watercress (Nasturtium officinale), and <br />cattails (TYPha spp.) (Spamer and Bogan 1993; Stevens et al. 1997b; <br />USFWS 1995). KASs have also been observed on water sedge (Carex <br />aquatilis) and smartweed (polygonum amphibium) (IKAMT 1998). <br />Ecological studies of the KAS population at VP (Stevens et al. <br />1997b) have provided evidence that KASs inhabit ~mulus and <br />Nasturtium patches in preference to secondary or associated <br />vegetation types. <br /> <br />The tolerance limits of environmental conditions for KAS are not <br />well known. A wide range of light exposure, soil characteristics, <br />and water quality was measured from both VP and 3L. Stevens et al. <br />(1997b) report the east-facing aspect of VP provides early morning <br />sun in the winter, allowing quick thaws from freezing nights, and <br />