Botanica Pacifica. A journal of plant science and conservation. 2018. 7(2): 127–141 DOI: 10.17581/bp.2018.07203 Liverworts from Attu Island, Near Islands, Aleutian Islands, Alaska (USA) with comparison to the Commander Islands (Russia) Stephen S. Talbot1*, Wilfred B. Schofield2† , Jiří Váňa3† & Sandra L. Talbot4 Stephen S. Talbot 1* ABSTRACT e-mail: [email protected] The liverwort flora of Attu Island, the westernmost Aleutian Island in the United Wilfred B. Schofield2 † States, was studied to assess species diversity in the hyperoceanic sector of the 3 † northern boreal subzone. The field study was undertaken in sites selected to Jiří Váňa represent a spectrum of environmental variation, primarily within the eastern Sandra L. Talbot 4 part of the island. Data were analyzed using our own collections on Attu Island, e-mail: [email protected] supplemented with information from published reports to compare bryophyte distribution patterns at three levels, the Northern Hemisphere, North America, the Commander Islands of Russia, and Alaska. A total of 112 liverworts were 1 U.S. Fish and Wildlife Service, identified and a substantial number, 34 species (30%), were new reports from Anchorage, AK 99503 USA Attu Island and one was new to Alaska. Geographic elements dominating the 2 Department of Botany, University of flora included arctomontane (26%), arctoboreomontane (23%), montane (20%), British Columbia, Vancouver, V6T 1Z4, and boreal (14%) species, while arctic species were almost absent (1%). The liv- Canada erworts of the Attu Island-Commander Islands region were widespread species 3 Department of Botany, Charles Univer- with over 70% circumpolar, or nearly circumpolar; nevertheless large gaps were sity, 128 01 Praha 2, Czech Republic present in some of their distributions with a floristic depression in liverwort dis- 4 Alaska Science Center, U.S. Geological tribution between Attu and the Commander Islands. Survey, Anchorage, AK 99508 USA Keywords: Hepaticae, phytogeography, northern boreal, hyperoceanic, Bering Land † Deceased Bridge РЕЗЮМЕ * corresponding authors Тэлбот С.С., Схофильд В.Б., Ванья И., Тэлбот С.Л. Печеночники ос­ т рова Атту, Ближние острова, Алеуты, Аляска (США) в сравнении Manuscript received: 13.11.2017 с печеночниками Командорских островов (Россия). Представлены ре- Review completed: 28.06.2018 зуль таты исследований флоры печеночников острова Атту, самого запад- Accepted for publication: 06.08.2018 но го алеутского острова в США, на основании которых проведена оценка Published online: 13.08.2018 ви дового разнообразия печеночников в гиперокеаническом секторе север- ной подзоны бореальной зоны. Полевые работы проводились на участках, от ражающих спектр изменений условий окружающей среды, прежде всего в восточной части острова. В анализ включены наши собственные коллек- ции с острова Атту и опубликованные данные других авторов. Проведен ана лиз распределения печеночников на трех уровнях: в Северном полу- ша рии, в Северной Америке, на российских Командорских островах и на Аляс ке. Было выявлено в общей сложности 112 видов печеночников, зна- чи тельная часть которых – 34 вида (30 %) – впервые отмечены на острове Атту, а один вид является новым для Аляски. Географический анализ фло- ры позволил установить, что в спектре географических элементов преоб- ла дают арктомонтанные (26 %), арктобореомонтанные (23 %), монтанные (20 %) и бореальные (14 %) виды, в то время как арктические виды почти от сутствуют (1%). Печеночники, совместно встречающиеся на острове Ат- ту и Командорских островах, на 70 % представлены циркумполярными или поч ти циркумполярными видами; тем не менее, существуют большие раз- личия между флорами печеночников Атту и Командорских островов. Ключевые слова: Hepaticae, фитогеография, бореальная зона, гиперокеанический климат, Берингийский мост суши Переведено редколлегией por tion of the archipelago. These windswept, often foggy INTRODUCTION vol canic islands are of considerable phytogeographic inte- From the northwestern portion of the North America rest because they occur along the southern margin of the land mass, the Aleutian Island Archipelago extends in an arc Be ring Land Bridge and function as an important region 1900 km into the northern Pacific Ocean from Unimak Is- for plant dispersal between Asia and North America (Elias land – the easternmost island – through Attu Island, the & Crocker 2008). Species dispersal occurs in at least two western most island in the United States, toward the Com- di rec tions, westward from North America along the Aleu- man der Islands of Russia, which comprise the westernmost tian Archipelago, and eastward from Asia toward mainland ©Botanical Garden-Institute FEB RAS. 2018 127 Talbot et al. Alaska and the more temperate North Pacific Coast. Attu cli mate change, including generally predicted warming air Is land is of particular interest because of its relatively close and ocean temperatures and accompanying changes in pre- pro ximity (ca. 300 km) to the Commander Islands of Rus- ci pitation, as well as synergistic interactions among specific sian Aleutian Islands. Hultén (1960) indicated the Aleutian factors characteristic of oceanic islands (Harter et al. 2015), Is lands belong to the same floral and vegetational province in cluding here the impact of ash on floras due to periodic as the Kamchatka Peninsula of Russia with the strongest vol canic activity characterizing the Aleutian Archipelago vas cular plant relationships occurring in the westernmost (An der son & Bank 1952, Heusser 1990). This research is lands of Attu, Agattu and Alaid. Of the approximately thus informs the DOI regarding biodiversity on lands that 530 vascular plant species comprising the Aleutian vascular the bureau manages. Because the Commander Islands fall flora, 70 % occur in both Alaska and Kamchatka. Attu Is- within the Commander Islands Biosphere Reserve and is land falls within the boundary of the U.S. Department of ad mi nistered by the Ministry of Natural Resources of the Interior’s (DOI) Alaska Maritime National Wildlife Refuge. Rus sian Federation, this research provides the Ministry with The Aleutian Archipelago is among the most dynamic va luable comparative biodiversity data as well. ecosystems on Earth, due in part to periodic volcanic erup- A total of 267 liverwort species are reported for Alas- tions that can eradicate island floras via thick ash deposits ka, excluding the Aleutian Islands, but given the relative- (e.g., Talbot et al. 2010). Liverworts are often among the ly poor his torical focus on Alaska liverworts and despite first terrestrial plant species to recolonize perturbed land- their ecolo gi cal significance and the richness of the Alaska scapes (Smith & Griggs 1932), and are known to deliver landscape, it is likely a number of new records are yet to mycor rhizal inoculum and improve the establishment of be reported (Sö derström et al. (2015). Liverwort collec- vas cular plants (Jongmans et al. 2001, Kowal et al. 2016). tions are repor ted from Attu Island by Clark & Frye (1948, The biodiversity of liverworts in the Aleutian Archipelago 1949), Davison (1993), Evans (1900), Frye & Clark (1946), is not well known (Söderström et al. 2015). The primary Hong (1980), Kon stantinova & Mamontov (2010), Macoun objectives of this study are to, 1) establish a checklist of (1902), Persson (1952, 1968) and Sharp & Hattori (1968). the liverwort flora of Attu Island, based on our collec- In total these reports list approximately 84 species for Attu tions and the collections of other researchers; 2) assign a Island (Davison 1993). common ness rating – abundant, common, uncommon, and rare – for each species; 3) record habitat information of STUDY AREA each species; and 4) collect voucher specimens of liverwort The Aleutian Islands are composed of a chain of se- species. Secondary objectives were to 5) describe the phyto- di men tary islands, eroded from older volcanic formations, geographic pattern of Attu liverworts with liverwort dis- and capped by steep volcanoes (Gallant et al. 1995). Attu tribution in circumpolar regions to provide a comparative Island is located in the westernmost Aleutian Islands gov- con text, including comparing the liverwort flora of Attu erned by the United States, at approximately 52.83°N, with that of the Commander Islands. The list also provides 173.18°E (Fig. 1); Attu Island was extensively glaciated base line data for detecting floristic shifts due to impacts of during late Quaternary time, probably during the Wiscon- Figure 1 Location of Attu Island, Alaska, and map of the liverwort collection sites. Circled numbers (1 – 28) are collection sites and listed in the Methods section 128 Botanica Pacifica. A journal of plant science and conservation. 2018. 7(2): 127–141 Liverworts from Attu Island, Alaska with comparison to the Commander Islands, Russia sinan Stage (Gates et al. 1971). The Commander Islands fred B. Schofield (WBS) during four periods: 1) July-August of Russia form a part of the Aleutian Islands with Bering 1988 (SLT and SST), 2) August 2000 (SLT, SST, & WBS), 3) Island (55.02°N, 165.98°E) and neighboring Copper Island. September 2002 (SST & WBS) and 4) August 2003 (SST). The geosystems of Bering Island may be divided into three All specimens are vouchered at UBC with partial sets de- types: plain, moun tain and coastal (Ivanov 2003); this clas- posited at DUKE and PRC. sification may be similarly applied to Attu Island. Based on Major collection sites are shown in Fig. 1, and are listed geological evidence (Tsvetlkov et al. 2010), the Commander below by site number (1–28) followed by a general geo- Is lands are older than more eastern islands of the Aleutian graphic descriptive name, latitude, longitude, and elevation. Ar chi pe la go; evidence of volcanism in the Commander Is- 1. Abraham Bay, 52°53'N, 172°47'E; 5 m; lands are dated to the Miocene. 2. Alexai Point, 52°51'N, 173°14'E; 195 m; A maritime climate prevails throughout the region. The 3. Beach Road, 52°50'N, 173°09'E; 5 m; ecoclimatic-ph ytogeographical system of Tuhkanen (1984) 4. Cape Wrangell, 52°56'N, 172°27'E; 195–488 m; cha racterizes the Aleutian Islands as northern boreal, hy- 5.