Bryophytes from Tuxedni Wilderness Area, Alaska

J Hattori Bot. Lab. No. 92: 91- 123 (Aug. 2002) BRYOPHYTES FROM TUXEDNI WILDERNESS AREA, ALASKA I 2 3 W B. SCHOFIELD , S. S. TALBOT AND S. L. TALBOT ABSTRACT. The bryoflora of two small maritime islands, Chisik and Duck Island (2,302 ha), com prising Tuxedni Wilderness in western lower Cook Inlet, Alaska, was examined to determine species composition in an area where no previous collections had been reported. The field study was con ducted from sites selected to represent the totality of environmental variation within Tuxedni Wilder ness. Data were analyzed using published reports to compare the bryophyte distribution patterns at three levels, the Northern Hemisphere, North America, and Alaska. A total of 286 bryophytes were identified: 230 mosses and 56 liverworts. Bryum miniatum, Dichodontium olympicum, and Or thotrichum pal/ens are new to Alaska. The annotated list of species for Tuxedni Wilderness expands the known range for many species and fills distribution gaps within Hulten's Central Pacific Coast district. Compared with bryophyte distribution in the Northern Hemisphere, the bryoflora of Tuxedni Wilderness primarily includes taxa ofboreal (61%), montane (13%), temperate (11%), arctic-alpine (7%), cosmopolitan (7%), distribution; 4% of the total moss flora are North America endemics. A brief summary of the botanical exploration of the general area is provided, as is a description of the bryophytes present in the vegetation and habitat types of Chisik and Duck Islands. KEy WORDS: Alaska, Tuxedni Wilderness, boreal zone, moss, liverwort, phytogeography. INTRODUCTION Tuxedni Wilderness Area on the western shore of lower Cook Inlet, Alaska, includes Chisik and Duck Islands (Fig. 1). As part of the Alaska Maritime National Wildlife Refuge managed by the U.S. Fish and Wildlife Service, Tuxedni Wilderness is a Class I air quality area (Clean Air Act, 42 U.S. Code 7401 et seq.). In accordance with its responsibility for ensuring high air quality in the Tuxedni Wilderness Area, the Service sought to assess the existing condition of wilderness resources in relation to air quality using the guidelines proposed by Fox et al. (1987). Applying these procedures, the first step in characterizing the plant component is to establish a floristic list that includes for each species distributional information and a commonness rating. Reports on the vascular flora (Tal bot et al. 1995) and lichens (Tal bot et al. 1992) have been published. The bryoflora, in contrast, is virtually unknown. The bryoflora of Alaska is relatively well documented, as summarized by the check lists of Frye & Clark (1937- 1947), Worley & Iwatsuki (1970) and Worley (1970). Studies pertinent to Pacific portions of Alaska appeared as early as that of Kurtz (1885) for the Chilkat region. The summary studies of Cardot & Theriot (1902, 1906) also contributed J Department of Botany, University of British Columbia, Vancouver, British Columbia V6T IZ4, Canada. 2 US. Fish and Wildlife Service, 1011 East Tudor Drive, Anchorage, Alaska 99503, US.A. 3 Biological Science Office, US. Geological Survey, Alaska Science Center, 1011 East Tudor Road, Anchorage, AK 99503, US.A. 92 1. Hattori Bot, Lab, No, 92 2 0 0 2 153'3B'W 37' 36' 35' 34' 153'33'W 60',1'N 10' Duck 09 ' G} lslc nd OS' 1 07' N II LAKE CLARK INLET NATIONAL PAR K SO'OS'N SCALE IN KILOMETERS AND PRESERV E Con tour inter va l = 152 meters Fig, I, The location and general topography of the Tuxedni Wilderness study area, Alaska, basic information, Evans (1900, 1914) gave scholarly assessments of the hepatics, and Eye rdam (1952) provided additional records, Holzinger & Frye (1921) presented the results of the U.S, Kelp Expedition, while Bartram (1938) provided a summary of the mosses known from the Aleutian Islands. Harvill (1948, 1950) made useful assessments of the geography of the mosses of Alaska. Persson (1946-1968), Persson & Shacklette (1969), and Persson & Viereck (1983) have published invaluable reports on scattered incidental collections of bryophytes, many of which were obtained accidentally as mixtures or teased out from vas cular plant herbarium specimens. Trelease (1902) and Eyerdam (1955) reported on exten sive collections of Sphagna. More recent studies have been made, unfortunately most of them unpublished. Three studies: - the Ph .D. thesis of 1. A. Worley (1972) concerning the bryophytes of the Alexander Archipelago and that of P. G. Davison (1993) concerning the hepatics of the Aleutian Islands, as well as a manuscript produced by D. K. Smith (1984) on the mosses of the same area represent invaluable summaries and syntheses. Peterson et al. (1980) have provided a summary of the mosses of Kodiak Island. Steere (1978) and Steere & Inoue (1978) provide a valuable assessment of the mosses and hepatics of Arctic Alaska. Despite an impressive number of investigations, the bryophytes of the Alaska Peninsu la and adjacent islands, including the Tuxedni Wilderness Area, remain inadequately docu mented. Access has been, and remains, a major impediment, but we have been fortunate in W B. SCHOFIELD ET AL.: 8ryophytes from Tuxedni Wilderness area, Alaska 93 Fig. 2. Aerial oblique photograph of Chisik Island, Alaska, from the northwest; Duck Island and Cook Inlet are to the left and center and the Tuxedni Channel and the Lake Clark National Park and Preserve are to the right. recent years, largely through support by the U.S. Fish and Wildlife Service, to acquire com prehensive collections from many localities in the area. The objectives of this study of Tuxedni Wilderness are to, 1) establish a checklist of the bryophytes, 2) assign a commonness rating - abundant, common, uncommon, and rare - for each species, 3) record habitat information for each species, 4) collect voucher specimens of bryophytes, and 5) compare the bryophyte distribution pattern at different ge ographic levels: the northern hemisphere, North America, and Alaska. GEOGRAPHICAL SETTING Location Tuxedni Wilderness is located at 60 0 08'N, 152°35'W at the head of Tuxedni Bay on the western side of lower Cook Inlet. Chisik, the larger of the two islands, is 10.5 km long and encompasses about 2297 ha, while Duck Island adjacent and east of Chisik is only 0.3 km long and includes 6 ha. Chisik Island is separated from the mainland by Tuxedni Channel which ranges in width from 1.1 to 3.2 km. The topography of Chisik Island is rugged (Wanek 1968). From the southern end of the island the land rises gradually along a ridge to the highest point at 815 m in the north ern portion where it drops precipitously along rock cliffs (Fig. 2). Both eastern and western 94 1. Hattori Bot. Lab. No. 92 2 0 0 2 slopes rise steeply from tidal flats to the ridge crest. The study area is found within the "Alaska-Aleutian Province" of the "Alaska Range (Southern Part) Section" of Wahrhaftig (1965) and the "Coastal Zone" of Racine and Young (1978). Climate Phytogeographically, the Tuxedni Wilderness Area is of interest because it occurs in the northern latitudinal limit of the "maritime zone" (Selkregg 1974: 5, Figure 3). Com pared with other climatic zones within Alaska, the maritime zone is distinguished by heavy precipitation, cool summers, and mild winters. Records from the Iniskin climatic station (59°45'N, 153°14 'W), 55 km southwest of Chisik Island on the western side of Cook Inlet, are applicable to the climatic regime for Tuxedni Wilderness (Arctic Environmental Information and Data Center 1989). Mean an nual temperature and precipitation recorded for Iniskin between 1954 and 1962 are 0.9°C and 1844 mm, respectively. In contrast, Homer (59°38'N, 151 °33'W), on the eastern side of Cook Inlet, located 80 km southeast of Chisik Island, is classified within the "transition zone" (Selkregg 1974). Homer has a slightly higher mean annual temperature, 2.9°C, and substantially lower pre cipitation, 632 mm, for the same reporting period. In addition, total annual snowfall at Homer, 1400 mm, is approximately one third that of Iniskin, 5103 mm. The drier climate of Homer reflects the influence of the Kenai Mountains, with elevations of 1220 to 1830 m. As air is lifted over the mountains, most of its moisture is deposited on the windward side (National Climatic Data Center 1987). Chisik Island receives higher precipitation, because southeasterly winds can penetrate Cook Inlet through an oceanic gap. Based on the ecoclimatic-phytogeographical system of Tuhkanen (1987: 130, Figure 18) for classifying the circumpolar zone, the study area falls within the middle boreal sub zone, hyperoceanic (02) sector, and humid (h) province. Using the formula of Hamet-Ahti et al. (1974) to determine climatic subzone, we calculated the mean annual biotemperature for Iniskin to be 3.9°C, placing it within the upper oroboreal subzone, the vertical equiva lent of the northern boreal subzone. The elevation of the Iniskin weather station (91 m) probably reflects colder conditions than the basal middle (oro-) boreal subzone at sea level. Geology and Soils Tuxedni Wilderness is underlain by highly fossiliferous sedimentary bedrock, Middle to-Upper Jurassic, (Detterman and Hartsock 1966), including siltstone, sandstone, and con glomerate. Surficial deposits occur on Chisik Island along the west-central shore (an allu vial fan) and on the northern end (elevated beach ridges). Soil development occurs on undifferentiated alluvium and coarse rubbly deposits on steep mountains and hills (Karlstrom et al. 1964). In a reconnaissance survey of the soils of Alaska, Rieger et al. (1979) mapped Tuxedni Wilderness Area within the "Typic Cryan depts, very gravelly, hilly to steep - Rough Mountainous Land Association" within the "Alaska Peninsula and Southwestern Islands Land Resource Area." According to Rieger et al. (1979), the dominant soils under 600 m elevation are Typic Cryandepts. These soils are covered with a mat of litter and consist of strongly acid, dark reddish brown volcanic ash W.

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