Alaska Arctic Tundra Vegetation Map

AVHRR false-color composite image - Vegetation Units - Bioclimate Subzones - Floristic Provinces
Substrate Chemistry - Elevation - Lake Cover - Maximum NDVI and Phytomass

Floristic Provinces

Select image to enlarge
PDF

This map is nearly identical to the Alaska portion of the Floristic Province map of the Circumpolar Arctic Vegetation Map. Only the boundaries of the map and scale are changed. Alaska is in the Beringian Province and has three subprovinces.

Floristic Provinces are used to explain the east-west variation in species distribution in the Arctic. The Arctic has a relatively consistent core of plant species that occur throughout the circumpolar region, but there is also considerable east to west variation in regional floras, particularly in southern bioclimate subzones. These differences are evident in the species listed in the bioclimate subzones. This variation is due to a number of factors, including different histories related to glaciations, land bridges, and north-south trending mountain ranges, which have influenced the exchange of species between parts of the Arctic. Alaska is included within the Beringian Floristic Province, and includes three of the 23 circumpolar Sub-Provinces: North Beringian Islands, Beringian Alaska, and Northern Alaska (Yurtsev 1994), (Walker 2005).

• Beringian Alaska sector

  "This sector has a vast latitudinal extension and is divided by two large bays, the Kotzebue and Norton Bays, cutting deep inland. It borders a Picea forest area along almost its whole length. In contrast to the Beringian Chukotka [sector] the Beringian Alaska [sector] is situated almost entirely in southern hypoarctic tundra subzone [= Subzone E] and characterized by a still greater importance of boreal (including woodland) species. A few endemics in the general Beckwithia, Douglasia s.s., Papaver and Smelowskia are found here."

  "Among the western co-differential taxa of the Beringian Alaska [sector], in common with the Chukotka Peninsula, there also prevail plants characteristic of more southern coasts of the Bering Sea and North Pacific, but there is a sufficient number of co-endemics (i.e. endemics shared by neighboring phytochoria) and subendemics of the maritime parts of Chukotka and Alaska (e.g. Artemisia globularia, Papaver walpolei, Rumex krausii, and Stellaria dicranoides = Arenaria chamissonis,) as well as predominantly Asian taxa (e.g. Oxygraphis glacialis, Rhododendron camtschaticum ssp. glandulosum and Saxifraga nudicaulis ssp. nudicaulis). The distribution pattern of many species is asymmetrical on the Asian and American side. Thus in Alaska, unlike Chukotka, Carex krausei, C. marina, Luzula rufescens avoid the coasts of the strait, while Rosa acicularis, and, to some extent, Dianthus repens and Silene repens, do not." (From Yurtsev 1994.)

• North Beringian Islands sector

  "This area includes the Diomede Islands in the central part of Bering Strait along with St. Lawrence Island and St. Matthew Island in the northern, shallow part of the Bering Sea. Unlike the offshore islands, these four islands lack the majority of species characteristic of either coast of the strait, with the exception of a few Asian and American taxa. True oceanic species are more important here mostly also found on the Aleutian and Commander islands, for instance Nesodraba grandis on Big Diomede (Ramonov) Island and Conioselinium chinense on the St. Lawrence Islands (Young 1971)." (From Yurtsev 1994.)

• Northern Alaska sector

  "This sector comprises the more continental (central and eastern) parts of the Brooks Range along with its northern foothills, and the Richardson Mts., as well as the Arctic slope of Alaska with its cold, true Arctic climate. The flora of the whole western part of the Brooks Range with its spurs and foothills is a transitional entity analogous, to some extent, to that of the Amguema area in Chukotka, with characteristic overlapping distribution areas of oceanic and continental (and other true Arctic) species. But the southwest-northeast gradient in both climate and floristic composition is well expressed even within the Seward Peninsula, [i.e. within the Beringian Alaska sector]."

  "Among the differential and eastern co-differential taxa of the North Alaska [sector] those with a disjunction over the central parts of the Beringian [group] (including steppe plants) predominate over the purely American taxa. The secondary gaps in the distribution areas of continental species can be attributed to the influence of the Holocenic sea transgression on the climate." (From Yurtsev 1994.) The eastern boundary of this sector is disputed as mentioned above.