310 Arctic Biodiversity Assessment Purple saxifrage Saxifraga oppositifolia is a very common plant in poorly vegetated areas all over the high Arctic. It even grows on Kaffeklubben Island in N Greenland, at 83°40’ N, the most northerly plant locality in the world. It is one of the first plants to flower in spring and serves as the territorial flower of Nunavut in Canada. Zackenberg 2003. Photo: Erik Thomsen. 311 Chapter 9 Plants Lead Authors Fred J.A. Daniëls, Lynn J. Gillespie and Michel Poulin Contributing Authors Olga M. Afonina, Inger Greve Alsos, Mora Aronsson, Helga Bültmann, Stefanie Ickert-Bond, Nadya A. Konstantinova, Connie Lovejoy, Henry Väre and Kristine Bakke Westergaard Contents Summary ..............................................................312 9.4. Algae ..............................................................339 9.1. Introduction ......................................................313 9.4.1. Major algal groups ..........................................341 9.4.2. Arctic algal taxonomic diversity and regionality ..............342 9.2. Vascular plants ....................................................314 9.4.2.1. Russia ...............................................343 9.2.1. Taxonomic categories and species groups ....................314 9.4.2.2. Svalbard ............................................344 9.2.2. The Arctic territory and its subdivision .......................315 9.4.2.3. Greenland ...........................................344 9.2.3. The flora of the Arctic ........................................316 9.4.2.4. Canada ..............................................344 9.2.3.1. Taxonomic structure .................................317 9.4.2.5. Alaska ...............................................345 9.2.3.2. Endemic species .....................................318 9.4.3. Pan-Arctic surveys ...........................................345 9.2.3.3. Borderline species ...................................318 9.4.4. Trends ......................................................346 9.2.3.4. Non-native species ..................................318 9.4.5. Conclusions and recommendations ..........................346 9.2.3.5. Origin and integrity of the Arctic flora ����������������319 9.2.3.6. Species richness in Arctic subzones ������������������322 Acknowledgements ...................................................347 9.2.3.7. Species richness in floristic provinces ����������������322 References .............................................................347 9.2.3.8. Hotspots ............................................326 9.2.4. Traditional use of vascular plants .............................326 9.2.5. Rare and threatened Arctic endemic species .................326 9.2.5.1. Rare Arctic endemic species �������������������������326 9.2.5.2. Threatened Arctic species ����������������������������327 9.2.6. Trends and monitoring efforts ...............................328 9.2.7. Conclusions and recommendations ..........................329 9.3. Bryophytes ........................................................329 9.3.1. Bryophytes in the Arctic .....................................330 9.3.2. Arctic bryofloristic studies ...................................332 9.3.3. Regional surveys of Arctic bryodiversity .....................332 9.3.3.1. Russia ...............................................334 9.3.3.2. Svalbard ............................................335 9.3.3.3. Greenland ...........................................335 9.3.3.4. Canada .............................................335 9.3.3.5. Alaska ..............................................336 9.3.4. Taxonomic structure of the Arctic bryoflora ..................336 Willows grow much faster now on the banks of Kolyma. 9.3.5. Large scale variation of species richness .....................336 » As well in the summer pasture areas along the Arctic 9.3.5.1. Longitudinal variation ...............................336 Ocean tundra willows are more plentiful and more now. 9.3.5.2. Latitudinal variation .................................337 9.3.6. Origin of Arctic bryofloras and distribution types ............338 On River Suharnaya the willow bushes are much bigger. 9.3.7. Trends ......................................................339 Reindeer herders of the Chukchi community of Nutendli, 9.3.8. Conclusions and recommendations ..........................339 northeastern Sakha-Yakutia, Siberia; Mustonen 2007. 312 Arctic Biodiversity Assessment SUMMARY The Arctic territory is divided into 21 floristic provinces and five subzones. These strongly differ in species rich- Based on published scientific literature, the diversity of ness and composition. There is a pronounced increase plants in the Arctic is reviewed. The plants are divided in species numbers from the northernmost high Arctic into three main groups according to essential differ- subzone A (102 species) to the southernmost low Arctic ences in anatomy, morphology and reproduction. These subzone E (2,180 species). A comparison of species num- are vascular plants, bryophytes (mosses and liverworts) bers per floristic province showed a range from approxi- and algae (micro- and macroalgae). As a whole, these mately 200 species for the rather heavily glaciated and three plant groups have the ability to perform photosyn- northern floristic province Ellesmere Land-N Greenland thesis. As primary producers they play a key role in the to more than 800 species for Beringian W Alaska. environment, since photosynthesis provides resources for all other organisms. Vascular plants and bryophytes Polyploidy1 (allopolyploidy) levels are high in Arctic (together with the lichenized fungi, the lichens) are the plants. Endemism is well developed. One hundred six main structural components of terrestrial vegetation species (and subspecies), or c. 5% of the Arctic vascular and ecosystems, while algae are more abundant in fresh plant flora, are endemic to the Arctic. The genera Pa- water and marine ecosystems. paver (poppy), Puccinellia (salt marsh-grass, goose grass), Oxytropis, Potentilla and Draba (draba, whitlow-grass) Our knowledge of the taxonomic diversity of these three are particularly rich in endemic species, and almost all main groups is very uneven. Although serious knowledge endemic species are forbs and grasses, whereas there are gaps still exist, our understanding of vascular plant di- no endemic woody species. Though the absolute number versity in the Arctic was recently improved considerably of Arctic endemic species increases from north to south, by the publication of the Annotated Checklist of the Panarctic i.e. from the high Arctic to the low Arctic, the relative Flora (PAF) Vascular plants (Elven 2011), a result of many percentage of endemic species decreases. years of laborious research by taxonomists associated with the Panarctic Flora Project. The Arctic bryoflora is The floras of the northern floristic provinces Ellesmere relatively well known, but a circumpolar Arctic check- Land-N Greenland, Svalbard-Franz Joseph Land and list of mosses and liverworts has not yet been finalized. Wrangel Island are relatively rich in Arctic endemic Knowledge of the circumpolar Arctic taxonomic diversity species. Ten Arctic endemic species are restricted to of algae is still rather fragmentary. Preliminary biodiver- Wrangel Island and underline the hotspot character of sity assessments have been made for Arctic marine algae, this high Arctic island. Twenty Arctic endemic species but there has been no attempt yet to synthesize knowl- are very rare, and as such are possibly threatened. edge of the diversity of Arctic freshwater algae. Knowl- edge of the biodiversity of terrestrial algae in the Arctic is Borderline species are primarily non-Arctic species just also very fragmentary. reaching the southernmost extent of the Arctic (subzone E). Taxonomically this is a rather diverse group of 136 The main difficulties in assessing biological diversity at vascular plant species in 91 genera and 45 families. subgeneric levels are the dissimilarities that exist in the taxonomic species concept and classification between Non-native species that occur as persisting stabilized the Arctic countries. Moreover, current species concepts introductions in the Arctic account for 5% of the flora from traditional morphological assessments are chal- (101 species). In addition there are 89 species native to lenged by the latest molecular phylogenetic analyses, the Arctic that also occur as stabilized introductions in which sometimes conflict with traditional classification. other parts of the Arctic. In addition, more than 205 non-native species have been recorded in the Arctic only The vascular plant flora of the Arctic is relatively poor. as casual introductions that do not persist. Non-native Approximately 2,218 vascular plant species (including sub- species mainly occur in and around settlements and species, apomictic aggregates and some collective species) towns, in particular in climatologically favorable parts of are recognized. This is less than 1% of the known vascular the Euro-Siberian Arctic. plant species in the world (c. 0.85% based on an estimated total of 260,000 species; Raven et al. 2005). Arctic vascu- No single, predominantly Arctic vascular plant species lar plants belong to 430 genera and 91 families, almost all is known to have gone extinct due to human activi- within the flowering plants (angiosperms). Gymnosperms ties in the last 250 years. There are no species in the are rare and species diversity