Notable vascular plants from Alaska in Wrangell-St Elias National Park and Preserve with comments on the floristics.

Cook, Mary; Roland, Carl

An inventory of the vascular flora north of the Bagley Icefield in Wrangell-St. Elias National Park and Preserve, Alaska, U.S.A., was conducted from 1994 to 1997. The objectives of the inventory were to assess the genetic diversity of the region, identify rare taxa and areas of phytogeographic interest and to assist park managers with planning and environmental compliance. The purpose of this paper is to present annotations for 212 of the most notable taxa with their Alaska-Yukon and Park distribution maps and to summarize the floristics of the Park. 832 species (887 taxa) were documented as occurring within the Park (approximately 54% of the Alaskan flora). Significant results from the inventory include: (1) nine additions to the flora of Alaska (Arabis calderi G. A. Mulligan, A. codyi G. A. Mulligan, A. drepanoloba Greene, A. lemmonii S. Wats., Carex petasata Dewey, Draba lonchocarpa Rydb. var. thompsonii (C.L. Hitchc.) Rollins, Festuca minutiflora Rydb., Najas flexilis (Willdenow) Rostkov. & Schmidt and Trichophorum pumilum (Vahl.) Schinz & Thell. var. rollandii (Fern.) Hultèn); (2) 331 range extensions; (3) the addition of 40 Alaska Natural Heritage plant taxa with a state rank of three or less for a total of 69 rare plant taxa in the Park s flora, and (4) the addition of 214 species to the Park s flora. The composition of our flora in percentages, with the rare flora in parenthesis, is: 25.8 (8.3) circumpolar, 10.8 (9.7) incompletely circumpolar, 32.2 (38.9) North American, 23.2 (11.1) amphiberingian, 0.9 (1.4) amphiatlantic and 7.1 (26.4) Alaska-Yukon endemic. The Alaska-Yukon and amphiberingian endemic elements are dominant in the Alaska Range, the Wrangell Mountains and in the Tanana, White and Copper River basins whereas the Cordilleran endemic element is dominant in the St. Elias and Chugach Mountains and Chitina River basin. These trends correspond to our understanding of plant migration after the Pleistocene Epoch from refugia in the Upper Yukon Valley, the Alaska Range and Beringia, the northern part of the Park being closest to these migration corridors, whereas the St. Elias and Chugach Mountains are at the northern end of the North American cordilleran migration corridor. Endemics may also have evolved from relict populations in unglaciated areas within the Late Wisconsin ice sheet adjacent to Lake Ahtna, on coastal refugia and on exposed sites in the dry northern interior of the Park bordering the Tanana Valley and the southeastern edge of Beringia. The rare flora was distributed somewhat evenly through the mountain ranges of the Park, but unevenly throughout the basin regions of the Park where the Chitina River basin had two to four times the number of rare species found in the other basins. There was a trend for rare plants to occur in the alpine zone, above 1200 m elevation, in xeric sites, in the alpine-herb talus slope plant community, on southerly aspects and on slopes of 20 40 degrees. Although the Park is protected, infrastructure development, visitor use in the backcountry in communities most likely to harbor rare plants, and global changes to the ecosystems are increasing. This inventory enhanced our understanding of the genetic diversity, phytogeography and distribution of our flora, however, there are still large areas in the Park that have not been surveyed, particularly in the coastal region, and we lack sufficient knowledge about most rare species (distribution, life history and population ecology) to develop protection plans.

Notable vascular plants from Alaska in Wrangell-St Elias National Park and Preserve with comments on the floristics.

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