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Flora of the Canadian Arctic Archipelago |
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S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, L.J. Gillespie, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, A.K. Brysting and H. Solstad |
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General Information |
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Contents |
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Introduction
This Flora of the vascular plants of the Canadian Arctic Archipelago is in DELTA electronic database format. It provides illustrated, interactive, identification to the more than 300 taxa known to occur on the Canadian Arctic Islands. There is also information on other species that occur nearby on Continental North America, and should be looked for on the islands. The Poaceae treatment was first released in 1995 (Aiken et al. 1995) in conjunction with a paper describing the methodology (Aiken et al. 1996). It represented the culmination of 11 years of work on Arctic grasses. The treatment of the Saxifragaceae was released in 1997 (McJannet et al. 1997; Aiken et al. 1998). The treatment of the nine families in the combined Pteridophytes and Monocotyledons of the Canadian Arctic Archipelago was available for review purposes from the authors in 2001. Treatments of the dicotyledon families have been released as produced, currently at http://www.mun.ca/biology/delta/arctic.
Porsild (1957, 1964) has been the authoritative Flora of the Canadian Arctic Archipelago for more than forty years during which time there has been considerable research on Arctic taxa of vascular plants (see references). Porsild (1957) provided limited classical keys to groups, often based on a single character that may be absent from a specimen to be identified. His taxonomic descriptions usually have fewer than 10 characters. For all taxa in this treatment, at least 50 characters were recorded and some have information for over 100 characters. The present product attempts to summarize the post-1957 literature, current thinking on the Arctic Flora as it is released in the Flora of North America, and information that has resulted from the Panarctic Flora project (Nordal and Yu. Razzhivim 1999; Elven et al. 2003). While much research is still required, this flora brings together the existing state of knowledge and should provide a framework for further research. It is a basis for people working with plants in the Canadian Arctic and the circumpolar Arctic regions. It is presented here as a CD-ROM, which has the advantage that more than 2500 images are available more quickly than from the Web, and it circumvents the uncertainty of how long Memorial University of Newfoundland is prepared to host the flora.
Information in this flora includes common names, place of valid publication, location of type specimens, and synonymy that attempts to consider all names that have been associated with the Canadian Arctic, particularly by Polunin (1940), Porsild (1957, 1964), Hultén (1968), Porsild and Cody (1980), and Cody (1996). The taxonomy and nomenclature currently used in North America, which is being presented by the Flora of North America as volumes appear, has been considered and has sometimes been anticipated after consultation with authors of treatments not yet published. In 1998, work on the flowering plants of the Canadian Arctic Archipelago became part of a Panarctic Flora initiative lead by Norway and involved all countries that have Arctic territories (Nordal and Razzhivin 1999). It resulted in the Panarctic Flora Checklist (Elven et al. 2003). This checklist suggested the name to be used for a given species and tried to represent the best consensus that could be achieved at the time, given differences in species concept and botanical traditions in the circumpolar area. After Elven became a co-author on this flora in 2000, his extensive work on synonymy for the Panarctic Flora Checklist (Elven et al. 2003) along with his work on compiling the original sources of chromosome number data (2002, personal communication) were incorporated for species occurring in the Canadian Arctic Archipelago.
The Panarctic Flora project has revealed many areas where much more work is desirable to clarify taxonomic and nomenclatural problems that require more research and proportionally how little botanical research work is being done in the Canadian Arctic relative to other Arctic countries. Most authors writing for the Flora of North America have not done detailed studies on the Arctic members of taxa they include or accessed the work of the Panarctic Flora Checklist. Where there are debates about the current nomenclature for a taxon, or differences between the names used in the Flora of North America treatment and the Panarctic Flora Checklist, this is documented and reasons for the name we have chosen are given in the Notes section following each taxon.
This flora also includes information on vegetative and floral morphological characters, distribution and habitat data. There are notes on ecology, indigenous knowledge, economic uses, and other miscellaneous information available from diverse literature sources that are indicated in the references. The databases include definitions of characters and often colour images or line drawings that are available to illustrate the character concepts used. Taxa are illustrated with photographs showing the habitats in which the plants grow, close-up images of the plants, and close-up details of characteristics that help confirm identification. There are maps with point references from vouchered collections made in the Arctic Islands. These are mainly based on specimens housed at the Canadian Museum of Nature (CAN), the Department of Agriculture Canada Herbarium (DAO) and limited additional records from Queens University (QT), Victoria University of British Columbia (UVIC), Gray (GH), Smithsonian Institution (US), Provo Utah (BRY), New York (NY), Oslo (O) and the Komarov Institute St. Petersburg (LE). Seven years after Porsild (1957), a second edition Porsild (1964) was published that contained new maps with additional data. To obtain more complete maps for this project, a similar time frame would probably be necessary. Unfortunately, it has not been possible to trace some of the more unusual records in Porsild’s maps and where this is the case, it is indicated. The database behind the maps is available from the Canadian Museum of Nature upon request.
This flora provides detailed information on over 340 (?) taxa known to occur or possibly to be found in from the Canadian Arctic Archipelago. In the first Flora of the Canadian Arctic Archipelago, Porsild (1957) summarized his findings in Appendix Table 1. In this table, he included approximately 40 species that he suggested had not been found but should be looked for on the Arctic Islands. It is difficult to make direct comparisons between the state of knowledge in 1957 (1964) and this current treatment because changes in species concepts, taxonomy, and nomenclature have occurred during the intervening years as the result of research. At this time we can report that [?] species anticipated by Porsild have been found and also [?] species that he did not anticipate have been collected. About 10 of these were discovered by the team of botanists on the Swedish Tundra Expedition (1999) who had about as many person hours of botanical collecting in one year as museum scientists have had at new sites in 10 years. [?] species that Porsild (1957) anticipated, have not been found. Especially those that occur on the coastal continental Northwest Territories should be looked for on South Eastern Victoria Island (Wollaston Peninsula: Forsyth Bay) opposite Bernard Harbour. This was a traditional area for the Copper Eskimos to cross from the mainland to the Island (Map Jenness 1991, p. 346). Plants were collected in the area by members of the Arctic Expedition, 1913–1918, and a list of plants collected by Diamond Jenness who made the crossing is given as an appendix (Jenness, 1991). He was not a trained botanist and the list of 41 plants he collected and deposited at the Canadian Museum of Nature suggests that he was more attracted to those with conspicuous flowers.
Porsild grew up in Disco, Greenland, and he suggested (Porsild 1957) several species that occur on that island that he thought should be looked for in the Eastern Canadian Arctic Archipelago. Where these have been checked it has often been found that the northernmost record of the taxon in North America is considerably south of Hudson Strait and as it has been judged less likely that they will be found on the islands, less data is presented for them.
Arctic has been defined as comprising all land surfaces lying north of the tree line, which in general follows the 10°C isotherm for the warmest month of the year. The position of this line across Canada is shown in the following map from the National Atlas of Canada.
Illustration. Maximum temperatures, July.
The position of the southern boundary of the Arctic, often referred to as ‘tree line’, has been a major source of discussion for the Panarctic Flora checklist, in relation to which of the species occurring at or near it should be included. It is being mapped by the CAVM team (2003). In general, the CAFF (Conservation of Arctic Flora and Fauna) groups use a rather wide and somewhat vague idea of Arctic as much of their work involves animals that annually migrate across the tree line. On Continental North America, there are predominantly Arctic taxa that occur within the southern limits of the tree line, and mainly boreal or southern taxa that reach the northern limit of their distribution at or around tree line. Data for some of these taxa from Continental North America, that Porsild (1957) anticipated might be found on the islands, have been included. This list is not definitive. Conversely, additional taxa that Porsild (1957) did not anticipate have been found on the islands, and full data on these taxa are presented.
Tree line is a zone rather than a line. Scott, (1996) described the transition from forest to tundra in terms of the shape and density of trees and recognized five different groups, or stages in the transition.
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v. |
Trees have full crowns, with little or no damage done by wind. |
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iv. |
A tree may have a zone of upwind abrasion where all the needles have been blown off the branches and even the branches have been blow away. |
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iii. |
Trees have a dense cluster of branches or basal rosette (basal mass, skirt or cushion) usually near the ground, where the snow builds up each year. As well as a zone of upwind abrasion there is a zone of total abrasion where all the branches and needles have been abraded off. The upper part of the tree that has all of the branches intact is called the flag. |
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ii. |
There is a basal rosette, but no true flag. The flag is important because if a tree does not produce a stem with an apical bud it may not reproduce sexually. |
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i. |
Stemless mats. There is only the basal rosette, which can either be elevated off the ground or grow within it. These stemless mats reproduce by cloning themselves. This happens when an older branch near the ground becomes weighted down and gets buried in the accumulating peat. The branch will root and turn upright becoming a new tree. |
Continuous forest is unambiguously below the tree line. About 100 km southwest of Churchill, Manitoba, there are areas of open forest where the trees are full-crowned indicating no damage from abrasion but collectively the trees never cover more than about 25% of ground surface. Where the abraded-crown forms occur in a stand they are said to form woodlands of the forest-tundra (taiga) zone. Sometimes this zone includes tight clumps of cloned trees or ‘islands’. The tundra is recognized either where there are no trees, or those that occur are stemless mats.
Porsild and Cody (1980) noted that the position of tree line on Continental North America has changed periodically, as demonstrated (a) by plant remains preserved in peat deposits, (b) by the presence of numerous woodland plants now localize in favored situations well beyond the present limits of forest, and (c) conversely by the presence of isolated pockets of tundra species that have survived within the forested region on rocky exposures or in bogs where competition from woodland species have been slight.
Illustration. The classification of trees at the forest-tundra transition zone, after Scott (1996).
Illustration. Open forest area with less than 25% tree cover. Note a foreground tree with a basal rosette and flags that have been only slightly suffered wind abrasion in the winter. Churchill, Manitoba.
Illustration. Stunted trees of the group ‘ii’ recognized by Scott (1996). The ‘trees’ have a basal rosette and flags that have suffered various degrees of severe wind abrasion. This area is between forest-tundra and tundra. Churchill, Manitoba.
Illustration. Isolated trees in the tundra beyond the tree line. Right of centre is an isolated clump or ‘island’ of group 2 trees in an otherwise tundra landscape. Left on the horizon are type ‘i’ trees that are merely basal rosettes. This area is considered tundra although occasional trees occur. Such trees probably reproduce only by vegetative cloning. Churchill, Manitoba.
Edlund and Alt (1989) discussed regional congruence of vegetation and summer climate patterns in the Queen Elizabeth Islands relevant to the mapped mini-tree-line, the line beyond which the two northernmost tundra woody species, Salix arctica and Dryas integrifolia did not grow. They found it was related to the July isotherm being less than 4°C.
By any of the botanically based definitions, all of the Canadian Arctic Archipelago is unambiguously Arctic although the southern regions are below the Arctic Circle (66°33’ N). The Arctic Archipelago has an area of 1.42 million square kilometres (about 549,000 square miles); approximately two-thirds of the area of Greenland. From east to west, the Archipelago extends from the southern tip of Baffin Island to the northwest corner of Banks Island, a distance of about 3000 km. In a north-south direction, it extends from Mansel Island, 62° N to Cape Columbia, on the north coast of Ellesmere Island, 83°39’N, a distance of about 3000 km.
The southern section is divided by the Boothia Peninsula into an eastern and western section. The principal topographical feature of the eastern section is Baffin Island (422,000 sq. km). Banks and Victoria Islands dominate the western section. In the northern part, or Queen Elizabeth Islands, Axel Heiberg, Ellesmere (214,000 sq. km) and Devon form a natural topographic and phytogeographic northern extension of the eastern Arctic. To the west, the members of the Svederup and Parry island groups form a more or less natural and phytogeographic unit.
Landforms
Geologically the land surface of the Canadian Arctic Archipelago is young, and repeated glaciations and deglaciations have had a profound impact in shaping land-forms and determining drainage patterns (Heginbottom 1989). Over the last two million years, the North has known several ice ages. The last one, the Wisconsin, began some 25,000 years ago. During that ice age, two huge ice sheets, the Laurentide and the Cordillera, covered most of North America. These ice sheets reached a maximum thickness of four and two thousand metre, thick respectively. Some time around 18,000 years ago, as the climate warmed, these huge ice sheets began to retreat. Soon an ice-free corridor appeared along the eastern edge of the Cordillera ice sheet, connecting the unglaciated areas in Yukon with the rest of ice-free North America. In doing so it provided a migration route for plants in the south to move north. By about 10,000 years ago, most of these two ice sheets had melted (Bone 1992). An area around Old Crow Flats in the Yukon and extending into Alaska is known to have been an ice-free refugeum during the last ice age and also an area from which plants returned to the formerly glaciated areas. Harrington et al. (1967) documented germinating lupin (Lupinus arcticus) seeds, at least 10,000 years old, found in lemming burrows deeply buried in permanently frozen silt of Pleistocene age from Miller Creek (64°00'N, 140°46'W), an unglaciated area of central Yukon. This suggests that some species may have been able to survive the last ice age in situ.
Illustration. Extent of ice sheets.
The remains of the last ice age are seen in the Canadian Arctic Archipelago in ice caps that occur on Baffin (Penny and Barns ice caps), Devon, Axel Heiberg (Franz Műller Ice Cap) and Ellesmere (Prince of Wales, Sydkapand and Agassiz and an unnamed ice cap). There is a small, unnamed ice cap on Melville Island. Ice caps flow outwards in several directions and submerge most or all of the underlying land, while a glacier flows in one direction and is normally confined to a valley. Glaciers exist on Axel Heiberg, Baffin, and Ellesmere Islands and are currently retreating. The retreat of a glacier in Sverdrup Pass, Ellesmere Island, was monitored by Svobodo, who had a field station there for many years (Svobodo and Freeman 1994).
During the advance and retreat of ice sheets two geomorphic processes took place. First the advancing ice sheet caused glacial erosion; later the retreating ice sheet deposited debris on the land. Glacial erosion took various forms, such as scraping off the unconsolidated material and plucking out huge chunks of bedrock. Where the bedrock was highly resistant, the rock was scraped and scoured. Evidence of such massive erosion is found on Baffin Island. During the retreat of an ice age, debris held in the ice sheets was deposited on the land, for example, as eskers: long, narrow ridges of sorted sands and gravels deposited from melt streams within the decaying ices sheet and ground moraine, or till, unsorted material deposited by a melting ice sheet or glacier.
Topography
One of the principal topographical features of the Arctic Archipelago is the mountain range that extends in a south to north direction from Labrador across Baffin, Devon, Ellesmere, and Axel Heiberg islands. This range, which in some sections reaches elevations of 2,400–3000 m (8,000–10,000 feet), strongly affects the climate of the rest of the Archipelago, because it acts like a mechanical barrier for the free flow of air from one side to the other.
Illustration. Relief map.
There are two major breaks in this mountain range; the first in Hudson Strait, which separates Ungava-Labrador from Baffin Island; the second is Lancaster Sound, which separates Baffin and Devon. Both are important physiography boundaries. Lancaster Sound and its westward projection through Barrow Strait, Viscount Melville Sound, and McClure Strait is another major topographical feature that divides the Archipelago into well-marked northern and southern parts.
Illustration. Place names.
Although most of the ground surface in the Canadian Arctic Archipelago is ice free in the summer, permafrost occurs below the surface everywhere except under deep lakes and rivers. Permafrost is defined as ground remaining, at or below, the freezing point for at least two years. At some sites the depth of permafrost may exceed several hundred metres while at more southerly sites its depth may be less than 10 m. The greatest thicknesses in Canada are over 1000 m deep in areas of Baffin and Ellesmere Islands. The southern extent of the permafrost is associated with the mean annual air temperature isotherm of 0°C (Williams 1986). The annual thaw of the surface, or active layer, varies with the texture and water content. In sand and gravel, the active layer may be deep, whereas in wet peaty soil the summer thaw may penetrate only a few inches. On sloping ground, mass wasting, in the form of soil creeps, mudflows, and other types of solifluction (processes of down-slope movement of often saturated soil caused by frost action) is common and widespread during early summer when the thawed surface layer reaches a critical point of water saturation. On level ground where the surface soil remains saturated because the permafrost layer does not permit melt water to escape, various forms of soil movement develop causing frost boils and mud polygons of various sizes. These movements result from convection currents cause by repeated thawing and freezing, and are most active under extreme arctic conditions such as are found in the northern parts of the Archipelago and at high elevations. Substrate movement is prevalent in surface material derived from the more rapidly weathering Palaeozoic rocks and from the freeze-thaw action that creates periglacial landforms such as pingos and patterned ground. Patterned ground is found throughout the Arctic except for areas of solid bedrock. The name refers to areas of symmetrical forms, usually polygons, caused by intense frost action over a long period of time. Ice-wedges are commonly associated with patterned ground. The general process of frost heave is for coarse stones to move to the surface and outwards. Ice wedges are typically V-shaped in section and the ice is vertically foliated. Large polygonal ground patterns usually indicate the present of ice wedges beneath the troughs delimiting the polygons. The polygonal patterns are best developed on poorly drained peaty flats. On hillsides a ribbon patterning that follows runoff water pathways from the top to the bottom is often conspicuous from the air. Especially in areas with less than 5% ground cover, the ‘ribbons’ often appear a darker brown green as they are areas of dense cryptogamic mats and some higher plants, while the adjacent ground appears bare and a lighter colour. Everywhere permafrost influences plant growth by cooling the soil and forming a barrier to water movement.
Soils
Physical scientists (Bostock 1964, Bird 1972, Graf 1987, and Slaymaker 1988) have described a set of geomorphic regions for Canada. Two geomorphic regions occur in the Canadian Arctic Archipelago.
Illustration. Geomorphic regions.
The bedrock geology of the Canadian Arctic Archipelago consist largely of a metamorphic Precambrian bedrock composed of mainly granite and gneiss and of a lower Paleozoic sedimentary rock composed of a major calcium carbonate complex (Dyke 1984, Edlund and Alt, 1989).
Areas with underlying Canadian Shield tend to have more acidic or circumneutral substrates; those of the remaining Arctic Islands are more calcareous and have a distinctly alkaline pH.
Lake waters located on the Shield, such as on Baffin Island, are generally poorly buffered, low in conductivity and with relatively low pH values. Magnetic susceptibility values of lake sediments from this region are higher due to the leaching of aluminum and iron from the bedrock. Lakes on carbonate bedrock are typically well buffered with high pH values due to the presence of the calcium carbonate complex (e.g. Lim et al., 2001; Pienitz et al., 1997a,b).
Floras differ markedly between areas with acidic soils and areas of limestone that have many basophile species but lack acidophile species Soil factors rarely coincide with other environmental boundaries. This is strikingly apparent in the plant collections from around Holmen, Victoria Island, where there are several records of acidophile species that on that island, which is predominantly covered with calcareous till.
Illustration. Surface materials map.
The surface materials map shows that the Holman area has a rock formation unlike the calcareous till that covers most of Banks Island and much of Victoria Island and this suggests a major factor influencing plant distribution.
Sylvia Edlund, who did field work with teams from the Geological Survey of Canada, incorporated excellent substrate information into the herbarium labels of specimens which she deposited at the Canadian Museum of Nature herbarium, but few other plant collectors have done so. To encourage botanist to record landscape information a character list in Delta format describing soil landscapes, is presented in Appendix 2. It is based on Sheilds et al. (1991). This appendix has been offered to Gould et al. of the CAVM team for their consideration in mapping Arctic vegetation (personal communication Jan. 2003).
True zonal soils are not found in most of the Arctic (Bone 1992). Periglacial features, such as bare rock and a variety of unconsolidated gravels and sand, form the ground surface. Peters and Walker (1972) reported on soils at the Truelove Lowlands, Devon Island (76°40’N, 84°40’W). They studied several sites in the area including a beach ridge, a sedge meadow, and a large peat mound. They found that most of the soil profiles were low in available nutrients, although where there was a high concentration of organic material the concentration of nitrogen and phosphorus was higher. These authors considered that compared with soils from more temperate regions the available nutrients were low. Water holding capacity of all the soils in the area was found to be very low due to their course, sandy, and gravely nature. Soils on the beach ridge were considered droughty because of their exposure and coarse texture. Although such soils can be saturated during the spring, any moisture that falls on them during the growing season percolates readily into the soil.
Where thin soils have formed in the continuous permafrost zone, they are often classified as cryosols (soils which have an active or thawed layer of less than one metre in depth). Under these conditions, soil-forming processes work extremely slowly because soil temperatures are often just above the freezing point. In the most barren zone, freezing temperatures occur almost daily and permafrost is present near the surface throughout the year. The conditions are an extreme form of fell field. Some authors use the term ‘polar desert’ to describe such barren lowlands (e.g. Svoboda and Freeman 1994; Elvebakk 1999). Others object to the word ‘desert’ arguing that even where the surface soils appear dry and there is minimal precipitation (for example, north-eastern Ellesmere Island), there is constantly water available for plant growth from melting of the top of the permafrost in summer which releases water that seeps up through the soil around plant roots even when the visible ground surface is desert-like dry (Yurtsev, 1994). In areas called ‘polar deserts’ or ‘zone 2’ (CAVM team 2003), wind-swept, desert-like stony barrens or clay flats, flat-topped domes, rolling hills, or extensive flat terraces are common features wherever Paleaozoic rocks predominate. Such habitats carry a sparse vegetation of xerophytic, vascular plant species with tufted habit. the plants are commonly subjected to frost heave and the species that have successfully colonized are generally confined to the depression between polygons. Woody species, especially members of the heath family are lacking. In contrast to the dry desert-like conditions, which are in areas that can be relatively ‘warm’ in summer, some of the most barren sites in the Canadian Arctic are desert-like in their lack of higher plant species, but relatively wet on the ground surface, for example on the western side of Prince Patrick Island where the mean July temperature is less than 4°C (Zone A Elvebakk, Elven and Razzhivin 1999; Zone 1 on the CAVM map personal communication 2003).
Climate
The Archipelago has a distinctly arctic climate and, with the exception of the east coast, decidedly continental in character. During July, the average temperature is below 10°C.
It is noteworthy that there is surprisingly little difference between the summer temperature in the southern and northern parts, although the Archipelago extends over more than 20 degrees of latitude. This is fundamentally important when considering distribution and growth of plants.
Illustration. Maximum temperatures, July.
As summer approaches the mean temperatures rise gradually and relatively uniformly throughout the Archipelago, so that in June, they vary little from place to place, except along the coast bordering the Polar Seas, on ice caps and at high elevations. The uniform summer temperature is due to the cooling effect of the cold seas, which surround the islands, and are largely ice-covered even in summer. A secondary effect of the cooling influence of the cold seas is the formation of a low cloud cover during July and August which prevails over most of the Archipelago and absorbs a large part of the solar heat that otherwise would have reached the ground. Researchers working from the Polar Continental Shelf Base on Cornwallis Island at Resolute Bay are familiar with the frequent fogs that close the airport, especially in August.
In winter, the influence of the sea has the opposite effect, because the sea, despite its ice-cover, is then often much warmer than the surrounding land areas. Although the monthly mean winter temperatures are low, the absolute minimum temperatures are much above those of the interior northern Continental North America far to the south, or Antarctica.
Illustration. Minimum temperatures, January.
Winter arrives at the end of August in the High Arctic and by the end of September in most of the Low Arctic. The first day of continuous snow cover for Iqaluit, Baffin Island, is usually about 20 September. Spring does not come until mid-June in most places; the last day for frost in Iqaluit is usually about 21 June. It snows least in the Eureka-Lake Hazen region (about 45 cm) and most in southeastern Baffin Island (up to 600 cm). The mid-winter is very cold and continuously dark: for about 45 days in the middle-arctic region around the 70th parallel, and for 120 days at Eureka 80°N. During the two coldest months, January and February, temperatures average from about –25°C in the south to about –35°C in the far north adjacent to the Arctic Ocean. Eventually the Arctic Archipelago north of the Arctic Circle has continuous sunlight, 140 days from April to September at Eureka.
Mesoclimate
Meso-scale climate patterns in the Canadian Arctic can be largely explained by physiographic factors (Atkinson, 2000). In regions that are governed by the northwesterly flow of the atmospheric circulation from the central Arctic Ocean, coldest summer temperatures occur. For instance, the extreme arctic ecosystem of the western Queen Elizabeth Islands is a result of the persistent airflow from the central Arctic Ocean. The high mountain range across Baffin, Devon and Ellesmere Islands act as a mechanical barrier (Rae, 1951) and bring about summer temperature maximums (Edlund and Alt, 1989). In the Queen Elizabeth Islands, the inter-montane zone of Axel Heiberg and Ellesmere Islands near the Frosheim Peninsula and the Lake Hazen area, are known oases, as is the area around Alexandra Fiord on the eastern side of the island (Edlund et al. 1989; Svobodo and Freeman 1994). Other polar oases occur Island in a series of lowlands on the northeast side of Devon, Island Sverdrup (26 km2), Sparbo-Hardy (86 km2), Skogn (13 km2), and Truelove (43 km2) Similar areas occur on Bathurst Island at Polar Bear Pass, Melville Island at Sherard Bay, and Prince Patrick at Mould Bay. South of the Parry Channel there are known oases on Baffin Island at Burwash Bay (Jacobs, personal communication 1986) and suspected oases in areas were willows over 2 m tall occur at Willow Creek off the Soper River in Southern Baffin Island, on Southampton Island, near Coral Harbour, and Melville Island, near Minto Inlet. At oases, greater snow accumulation occurs within more hilly and mountainous regions. This protects plants during the winter and increases moisture from melting snow during the summer (Remmert, 1980). Oases zones are covered by vegetation that is dense and diverse with a rich flora, a high total extent of plant cover, and the diversity of plant communities (Edlund and Alt, 1989). They are atypical of the latitudinal region, which is considered mostly Polar Desert (Muc and Bliss, 1977).
Microclimate
Differences between soil-surface and air temperatures can be considerable and are largely influenced by direct insolation and wind velocity (Soper and Powell 1985). These authors recorded that at Lake Hazen, (Ellesmere Island) on 23 May 1958, surface soil temperatures as high as 21–24°C were recorded on a south-facing slope, a full two weeks before the air at the screen height for measuring temperature (1.5 m) rose above freezing for the first time. On 23 May day the maximum air temperature recorded at the screen was only -5.6°C. Similar observations have been made by other researchers, (Sørensen 1941, Bliss 1956, Bliss and Svobodo 1984, Svobodo and Freeman 1994). In the Lake Hazen region a south-facing 30° slope receives about 15% more of the possible total radiation than a horizontal plane. Slopes with an exposure to the other cardinal directions are at a disadvantage, fore example, a steep north slope would receive less than half that received by a horizontal plane. At high latitudes, the microclimate is ameliorated in the growing season by the decline in the diel fluctuation of sun altitude so that temperatures remain relatively stable under constant daylight and ‘nocturnal’ inversions are largely absent with the ground remaining warmer than the air throughout the summer. The results are that the frost-free growing season at ground surface level may be 3–4 weeks longer than screen temperatures would suggest.
The annual mean precipitation is low everywhere in the Archipelago; so low that, were it not for the permafrost found close to the surface, large areas in the Archipelago would be entirely without vascular plants.
Illustration. Mean annual precipitation.
Winds
Everywhere wind action affects plant growth unfavourably, not only by its cooling and drying effect in summer or winter on plant stems and foliage, but also by the mechanical abrasive effect of drifting sand and in winter by tiny snow crystals, which at extreme low temperatures become very hard and gritty and contribute to shaping trees near tree-line. Wind deposition of loess is active, especially in mountainous parts of the Archipelago where the spring run-off from ice caps and large permanent snowfields causes the formation of large erosion fans, shallow streambeds, and floodplains from which high winds in later summer pick up fine silt. Locally near ice caps, the deposition of fine silt may be so rapid that only certain species can successfully cope with it.
Snow
Two types of plant habitats closely related to snow cover are of considerable importance in the arctic landscape. The first is an arctic-alpine habitat for which the ecological term snow-bed is used. By this is meant a place where, owing to topographical features, large masses of snow accumulate each winter. Plants growing on snow-bed habitats enjoy the protection afforded by the snow cover and are assured of continuing water supply from the melting snow throughout the growing season but must be adapted to an even shorter growing season than those occupying more exposed areas. In unfavourable seasons the snowbed habitat may remain covered by snow so late that the plants growing there may not have sufficient time to ripen their fruits, or even time to flower. For this reason only certain species of plants can successfully occupy snow-bed habitats.
The snow-patch is a more arctic plant habitat, usually a rather shallow depression in the landscape, where owing to the prevailing wind a snowdrift forms regularly each winter, affording protection for the plant cover beneath it. The snowdrift melts early and may not keep the habitat moist throughout the growing season. In the high-arctic landscape, plants with woody aerial stems, such as willows and heaths, are found chiefly on snow-patch habitats. To the botanist, but also to the construction engineer or road builder in the Arctic, snow-bed and snow-patch plants are reliable guides to the type of snow cover that the area receives in winter.
Plants
Microflora
Because of the low temperatures, organic decay by bacterial action is greatly reduced and consequently nitrates, phosphates, and other nutrients needed by plants are deficient. On Devon Island, thin section studies of a beach ridge and a meadow soil found that there was very little decomposition of organic matter as plant remains and insect fecal pellets were readily observed (Peters and Walker 1971). Where these nutrients are supplemented, arctic plants respond with lush and luxuriant growth. Thus, sites near fox dens, owl perches, bird cliffs, lemming burrows, animal dung, skeletal remains, around present and past human habitation, and sites where garbage has been burned, often stand out in contrast to the otherwise drab and often uniform arctic landscape.
Illustration. Garbage-dump habitat where burning had occurred previously. The plants at the site are much taller than those on the surrounding tundra.
Bacteria, algae, and micro-fungi are principal agents of decomposition in freshwater and land habitats. About 300 species of saprophytic or parasitic micro-fungi occur in the Canadian arctic islands (Saville 1974). Even in the severe climate of Ellef Ringnes Island at Isachsen, there are about 85 species of fungi where only 49 species of vascular plants have been recorded (Saville 1963). Algae make up a substantial part of the soil microflora. In fresh waters, extraordinary diversity has been found among the phytoplankton (Hobbie 1973). Many species live even in typically oligotrophic lakes, or lakes that are turbid from rock flour introduced by glacial melt streams. These algae appear to be nutrient-limited in the north, and are much influenced by patterns of lake circulation that release nutrients from the substrate.
Early research in freshwater algae of the Canadian Arctic was limited to two major studies. The southern party of the Canadian Arctic expedition (1913-1918) identified 117 taxa, of these 20 were cyanobacteria and 107 were from the traditional Chlorophyta. The sampling was restricted to the mainland and a few coastal islands. The first study of algae in the Arctic Archipelago was in 1939–1940 by Weldon and Ross (1947). Dr. Roy M. Weldon from Cambridge University identified 383 taxa of algae (excluding diatoms) and R. Ross from the British Museum identified 192 diatoms.
Since the 1950’s, phycological research has increased exponentially, from floristic surveys to nutrient cycling studies and finally to indicators of environmental and/or climate change in the arctic. After the 1957–58, extensive biological monitoring program in the Lake Hazen region of northern Ellesmere Island, 225 taxa (excluding diatoms) were identified from productive ponds, wetlands, and small lakes in the area (Croasdale 1973). Subsequent phycological research shifted south to Devon and Cornwallis islands and changed from floristic to predominantly ecological studies (Bliss 1977). Research on Cornwallis Island centered on lake ecosystems and the implications of nutrients on algae (Kalff & Welsh, 1974). On Ellesmere and Devon Islands, studies centered around wetlands and ponds, with special emphasis on cyanobacteria and nitrogen cycling (Capin et al. 1991, 1977, Henry and Svoboda 1986). Sheath et al. (1996) conducted stream macroalgae surveys across the arctic identifying 35 taxa covering four phyla. More recently, research has centered on diatoms, their ecology and their potential as paleoecological climatic indicators. The first paleolimnological study using diatoms was on Cape Hershel showed distinct changes in the regional climate over the last 150–200 years (Smol 1984). Current paleolimnological studies using diatoms show climatic warming across the Arctic Archipelago (e.g. Douglas et al. 1994, Gajewski et al. 1997, Ludlam et al. 1996, Wolfe 1995, 2000, Smith 2002, LeBlanc et al. submitted).
Other ecological research employing algae includes nutrient studies on Cornwallis Island (Douglas and Smol 2000). More recently, ecological studies on environmental processes include cyanobacterial films in marl deposits (Vézina and Vincent 1997), and even algae surviving the postulated snowball earth (Vincent et al. 2000). Recent floristic studies across the Arctic Archipelago have focused on the distribution of diatoms. To date, 360 taxa have been identified (Hamilton et al. 1994) with still hundreds to be identified and described. The paucity of floristic research on other algae is evident with only about 400 taxa recorded in freshwaters, mainly members of the Chlorophyta, Chrysophyta, Pyrrhophyta and Rhodophyta.
In certain places, there are cryptogamic mats that are dark in colour and composed of several cryptogamic species, usually including blue-green algae that fix nitrogen that becomes available to plants. Such ‘enriched’ local areas often harbour interesting micro-flora, composed partly of species that are ubiquitous and partly of species that are rare and entirely confined to these habitats. For this reason, these ‘oases’ in the arctic ‘desert’ are often species rich (Gold and Bliss 1995, Gold 1998).
Miller and Laursen (1974) reported that much of the below-ground fungal biomass appears to be mycorrhizal. Kohn and Stasovski (1990, 1994) sampled 24 species of plants at Alexandra Fiord, Ellesmere Island 78°53'N, 75°55'W and found that while 19 species showed some irregular colonization of rhizosphere fungi, or endophytes, only 11 species could, by the extent of the morphology and the extent of the fungal colonization, be classified as mycorrhizal. They considered the paucity of VA-mycorrhizal colonization in herbaceous species at the site was notable, especially when compared to reports for the same species from other arctic and alpine sites particularly in Russia and Alaska. Dalpé and Aiken(1998) examined 197 plant-root-systems and soil rhizosphere from around the roots of fescue grasses collected in the high Arctic, many from northeastern Ellesmere Island near Eureka. These authors found 28% were associated with arbuscular mycorrhizae fungi (AFM) and five species were extracted from indigenous soils and which suggested that the AFM isolated from the Arctic zone may have developed strains with physiological behaviour that makes them better adapted to the short growing season.
Vegetation
The vegetation is one key to understanding northern ecosystems not only because it determines terrestrial primary productivity and hence the basis of food chains, but also because locally it can magnify or reduce the impact of prevailing environmental conditions. Many schemes have been produced for subdividing the patterns observed in Arctic vegetation. The classification of vegetation was reviewed by Alexandrova (1980) and is still being discussed (Elvebakk 1999, and CAVM Team 2003). Sometimes the subdivisions are based solely on vegetation, but often other factors, such as climate or soils, have been taken into consideration. A circumpolar map of phytogeographic zones was published by Talbot et al. (1999) and a more detailed arctic vegetation map is being produced by the CVAM Team (2003). The Panarctic Flora project has worked on delimiting zones and making sectorial subdivisions of the Arctic as a basis for comparing plant distribution information to accompany the plant checklist (Elvebakk et al. 1999). These products are at best only very general guidelines.
The composition of communities appears to depend on six variables: climate thatimposes a major temperature-based zonation; local climates or microclimates that modify this overall pattern; drainage that controls the summer water regime and has some effect on frost action; nutrients that are in limited supply in most arctic soils;. local soil type which is influenced by climate and drainage, and in turn influences soil stability and fertility; and snow cover that controls the duration of the growing season.
Danks (1981) concluded that northern vegetation is heterogeneous and can change over short distances so that simple zonations cannot be recognized even at a moderate scale. Northern plant communities form a mosaic that transcends purely latitudinal zonations. He substantiated this statement with maps of the distribution of sedge-moss meadow oases in the Arctic Archipelago (Babb and Bliss 1974; Bliss 1977), noting that they cover less than 2% of the land area and are scattered.
Illustration. Distribution of richly vegetated sedge-moss meadows in the Canadian Arctic. After Babb and Bliss (1974).
Danks (1981) also drew attention to the heterogeneity of arctic vegetation on Ellesmere, Axel Heiberg and Devon Islands; this was mapped by Beschel (1970).
Illustration. Heterogeneity of arctic vegetation. (a) Ellesmere, Axel Heiberg, and Devon Islands (Beschel 1970): 1, ice caps; 2, polar desert; 3, Luzula steppe; 4, polar steppe; 5, Dryas tundra; 6, Cassiope tundra. (b) Novaya Zemlya (Alexandrova 1960 in Tedrow 1977): 1, ice caps; 2, northern variant of alpine polar desert; 3, southern variant of alpine polar desert; 4, northern variant of polar desert zone; 4, southern variant of polar desert zone; 6, alpine arctic tundra; 7, northern variant of arctic tundra subzone; 8, southern variant of arctic tundra subzone.
In a detailed study of Saxifraga oppositifolia that was growing at Truelove Inlet, Devon Island, Teeri (1972) found plants in three distinct microhabitats that were differently adapted morphologically and the precision of the adaptations was exemplified as the populations occurred within a linear distance of less than 40 m. This is consistent with observations by Brysting et al. (1996) who found that S. oppositifolia shows the highest level of intra-population variation and poorest geographic structure of all the species they studied.
Plant Habit
Freeman et al. (1994) noted that even in the best growing conditions Arctic plants are subjected to severe environmental constraints and suggested that these have caused plants to evolve characteristic morphologies and survival strategies or a combination of the following list:
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a low growing structure which helps avoid scouring by wind-borne ice particles, while taking advantage of warmer temperatures occurring with a thin boundary lay of almost-still air close to the ground surface, |
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an evergreen habit that conserves valuable energy and nutrients by ensuring that foliage remains metabolically active for more than one growing season, |
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a longevity that ensures the continuous presence of species in habitats where the establishment of new individuals by seedlings can be difficult and infrequent, |
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a small requirement for nutrients in an oligotrophic environment, |
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a tolerance of desiccation and frost events during the growing season, |
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the capacity to begin growth immediately following snowmelt in the spring, with the growth often starting from stem and flower buds pre-formed at the end of the previous growing season. |
Many plants grow close to the ground in clumps, cushions, or mats. There is very little annual growth in such arctic cushion plants as Dryas integrifolia, Saxifraga oppositifolia, or Silene acaulis, or arctic sedges growing in clumps, such as Carex nardina. It is difficult to distinguish, by direct observation, the previous year’s green portion from that of the current year (Saville 1972). Close to the end of the growing season, in mid August green leaves turn red, without being all killed during the following winter. After snowmelt they are reddish brown but during the next two weeks new chlorophyll forms and the leaves turn green again. Svoboda (1972) reported that on Devon Island at Truelove Inlet, each shoot of D. integrifolia starts the growing season with 2.6 old, live leaves and has 5 green leaves on average in early August.
Illustration. Plants forming clumps or cushions. Top left. Papaver dahlianum Nordh. subsp. polare (Tolm.) Elven and Nilsson. An isolated, ‘old’, clump of plants growing inmoving sand on a river bank. The centre of the clump is dead suggesting that the original plant(s) has/have died off, or been buried by moving sand, and that offspring of the colonizing plant(s) have developed close to the initial establishment in the shelter that it provided. Banks Island, Aulavik National Park. Top right. Silene acaulis (L.) Jacq. A classic, compact cushion plant, growing on gravel. Nunavut, Baffin Island, Iqaluit. Middle left. Carex ursina Dewey. Plant growing in a clump or cushion with fringes of small Stellaria humifusa plants around the edges in a Puccinellia phryganodes saline meadow, Nunavut, Baffin Island, Iqaluit. Center. Saxifraga oppositifolia. Compact cushion-like plants in full flower, growing in Saxifraga barren. Nunavut, Ellesmere Island, Alexandra Fiord. Middle right. Silene acaulis. Underside of plant with a major tap root and many tightly packed branches that make up the cushion. Nunavut, Baffin Island, Iqaluit. Bottom left. Loiseleuria procumbens (L.) Desv. Close-up of a matted prostrate shrub with branches that interlace like the branches of pruned hedges. Growing in dense tundra over rocks on west shore of Baffin Island, Frobisher Bay, at Ogac Lake. Bottom right. Parnassia kotzebuei Cham. and Schlecht. Several plants with relatively tall flowering stems, growing close together in a ‘young’ clump in sand dunes behind the beach with brackish water. Plants consist of single stems to many-stemmed clumps 10–16 cm tall. N.W.T., Cape Dalhousie, 2–3 m above sea level.
Many species have marcescent aerial stems and leaves that die off after the current season’s growth, accumulate at the base of the plant, and build up as a thatch that provides insulation and traps moisture.
Illustration. Thatch. Dryopteris fragrans (L.) Schott. Plant with a basal cover of protecting, withered leaves. Finland: Inarin lappi, Kevojoki. Sept. 1996. Photographed by R. Elven.
Arctic plants are often like icebergs, with much more of the plant underground than above ground.
Many monocotyledons have fibrous roots that may be very extensive under the plants and are often much longer than the plants are tall.
Illustration. Long, fibrous roots. Carex fuliginosa Schkuhr subsp. misandra (R.Br.) Nyman. Roots much longer than the stems are high. Nunavut, Ellesmere Island, Scoresby Bay. Photograph by Mollie MacCormac.
Many plants store food for over-wintering in underground stems such as long rhizomes or in vertical stem zones (a caudex or caudices) at and below ground level
Illustration. Rhizomes and caudices. Left. Chamerion angustifolium (L.) Holub. Rhizome of a large and vigorous plant from Yukon, Ogilvie Mts, river flats along Dempster Rd. 30 July 1966. R.T. Porsild 371. Right. Potentilla vahliana Lehm. Small and compact plant with well developed, elongated and branching underground caudex tightly covered with leaf bases, the marcescent remains of previous seasons leaves, and a small compact tuft of current season's leaves. N.W.T. Victoria Island, Holman.
Most ferns have horizontal stems, but this remarkable specimen of Dryopteris fragrans from Baker Lake in Nunavut shows the underground portion of a fern stem, looking like a small tree trunk. The positions where previous year’s fronds were attached suggest that if this plant was producing 3–6 fronds a year, it was many years old.
Illustration. Fern with underground stem. Dryopteris fragrans (L.) Schott. Plant with above ground fronds arising from a mass of scales near ground level, and an old vertical underground stem with fine blackish roots. Inset shows close up of stem portion covered by leaf bases where fronds have broken off at articulations adjacent to the stem. Nunavut, Baker Lake. T.N. Freeman.
Stems often have woody development below soil level. This may occur because the plants are growing up through blowing silt deposits. Well developed, branching underground stems are more common in members of the Asteraceae and Rosaceae. Because nearly all tundra plants are long lived, Young (1971) suggested that tundra areas can be regarded as ‘dwarf forests’.
Leaves are often affected by the strong winds and the long hours of sunlight in the Arctic summer. Many arctic plants have leaves that are specialized to avoid this drying out. The leaves of the purple saxifrage are succulent and very close together. They have long hairs on the edges of each leaf and these hairs act like the fur around a jacket hood keeping the air close to the leaf from moving as much. The vegetative leaves are flat to catch maximum sunlight. The leaves on the flowering stem are erect around the petiole and shelter the stem from air movement. The leaves of several heath species and Dryas have edges that roll under so that they touch or almost touch and in doing so provide protection for the under surface of the leaf where the pores that take in carbon dioxide are on hidden among the dense hairs. These hairs are often like ‘duffle’ and very effective in preventing air movement near the leaf under surface.
Illustration. Curled, hairy leaves. Ledum palustre subsp. decumbens (Aiton) Hultén. Growing tip with a dense cluster of leaves covered with brown deciduous hairs. Note adaxial surface of the leaves curled under leaving a stripe of brown hairs on the abaxial surface. Aiken, 2002.
Plants cannot dispose of solid waste materials the way animals do. In the centre of the cells that make up the plant, there is a large vacuole, which accumulates waste until the cell dies. In situations where a plant is growing well it may produce more solid waste than it has cell storage for. At such times, the waste, predominantly in the form of calcite is excreted through one or more special large pores, called hydathodes, that occur in the tips of the leaves These white crystals are not usually visible after rain or wet snow, or when the weather is cold.
Illustration. Excreted calcite. Saxifraga oppositifolia L. Note hydathodes (white arrow) on the triangular ends of the fleshy leaves. Many hydathodes have white calcite deposits at leaf tip. Hydathodes are small openings on the leaf blades, which exude water. Nunavut, Cornwallis Island, Resolute Bay.
The leaves in the picture are about 2.5–4 mm wide. If you look closely at real leaves of the purple saxifrage, it is easy to see the solid waste as white dots when it is present. Some other arctic species, particularly other arctic Saxifraga, also have large hydathodes that may become conspicuously crusted with white deposits.
The ferns that grow in the Arctic prefer the shelter of cliffs and crevices among rocks. The horsetails grow close to the ground and have very tiny leaves. The club-mosses are also short plants with thick leathery leaves that are close together.
Only nine species of obligate fresh-water plants have been recorded so far from the Archipelago. All are rare, and are generally restricted to small shallow ponds that become free of ice early in the spring and some of the species rarely, if ever, flower. Only three species, Pleuropogon sabinei, Ranunculus confervoides, and R. hyperboreus, range north of the 80th parallel.
Several monocotyledons grow in water or wet meadows. Most have leaves that die back over the winter and form a thatch around the base of the plant. Many grasses have leaves that fold(e.g. Poa) or roll, (Festuca, Puccinellia), so that the margins enclose, forming a zone of still air surrounded by leaf. The stomates are on this surface of the leaf and absent from the surface that is exposed to the elements.
Plants like fireweed (Chamerion latifolium) and mountain sorrel (Oxyria digyna) have leaves and stems that die off during the winter and are seen as ghosts of themselves early in the following spring.
Illustration. Dead leaves in spring. Oxyria digyna (L.) Hill. Very early season plant with a few new green leaves and developing red inflorescences growing in Dryas mat. Grey ‘ghosts’ of last years leaves persisting early season. N.W.T., Banks Island in Aulavik National Park. Aiken, SA99-006.
Plant reproduction
Many arctic plants are characterized by polyploidy, self-pollination, apomixis and agamospermy. That such reproductive systems may be involved is often indicated when a range of chromosome numbers is known for what is apparently a single species of plants. Such reproductive systems may help to meet the rigorous conditions and confer stability to the genome in the face of unpredictable short growing seasons.
Indigenous Knowledge
The people who have lived on the Canadian Arctic Archipelago for centuries have built up an extensive knowledge of the plants and uses for them. Porsild (1937) described edible roots and berries of northern Canada. During the summer of 1938, Anderson (1939) traveled with the U.S. coast guard and visited Eskimo villages of Northern Bering Sea and Arctic Alaska. He reported on the uses of plants by local people while noting that the diet of the Eskimos was almost exclusively of animal origin and the total portion of vegetable intake was very small. The food plants growing in the vicinity of the villages indicated that little had been gathered. Anderson (1939) observed that considering the small amount actually consumed, he found the number of plants used was surprisingly large, although not all species were used by all people in every village he visited.
Various methods were used to prepare plant material for consumption (Anderson 1939). Some plants were eaten raw, the same way as we eat lettuce or celery. Another method was to use either scalding or cold water and then allow the material to ferment, the preparation being ready for consumption when the proper stage of fermentation was reached. This process was called ‘souring’ and sometimes sugar was added to the soured material. Often the material was boiled and eaten. One of the commonest methods of use was to immerse the plant material in oil. This way it could be preserved for winter use. Whale blubber, seal oil, and at times caribou tallow were used.
Porsild (1945), possibly in response to pressure from the Second World War, produced a mimeo on ‘emergency food in arctic Canada’.In a paper on edible plants of the Arctic, Porsild (1953) summarized literature on the subject and drew on his ability with Scandinavian languages to report on the findings of Kjellman (1882) among the Chukchi in Russia, his experiences growing up in Greenland, and the work of Rodahl (1944, 1945, 1949, 1950). He noted that in Greenland several species of seaweed, including Thodymenia palmate and Laminaria species were eaten raw, dipped in boiling water or with seal oil so that an estimated 50% of the vitamin C intake of the east Greenland Eskimos was derived from marine algae (Rodahl 1950). Porsild (1953) noted that many different kinds of edible mushrooms and puffballs occur throughout the Arctic, especially near the southern fringe of the tundra where in mid-summer and early autumn bushels of the fungi may be collected. In 1953, he stated that no poisonous species had been detected north of the tree line although the deadly toad stood (Amanita phalloides) had been found in below tree line in the upper Mackenzie basin and in the Yukon.
Commenting on vascular plants, Porsild (1953) noted that everywhere in the Arctic, plant life is too sparse, dwarfed and poorly developed to make any considerable contribution to human food supply and that the dependence on vegetable food varies from group to group according to tradition and according to what plants are available in the area. Drawing on his experiences in Alaska, growing up in Greenland, and fieldwork in the Arctic Archipelago he stated that to the most northerly tribes (ones living in the Archipelago) the use of vegetable food is purely incidental and largely limited to the partly fermented and pre-digested content of the rumen of caribou and muskoxen. By contrast, in the diet of Eskimo of southwestern Greenland, Labrador, and western and southwestern Alaska, vegetable food constituted a regular, if not very large item.
In 1953, the plants used by Europeans in the Arctic, mostly in emergencies, had generally been different species from those used by the aborigines, and in vitamin content of lesser value (Porsild 1953). There are numerous examples of arctic expeditions that had made use of lichens, especially ‘rock tripe’ or ‘tripe-de-roche’ of the early Canadian voyageurs, beside mushrooms, puffballs, and scurvy grass, none of which were ever eaten by aboriginal tribes. Likewise berries such as the mountain cranberry and bilberry and to a lesser extent baked-apple are perhaps the most frequently used by Europeans, whereas these fruits are generally ignored by aboriginal peoples who prefer the crowberry, which is not favoured by Europeans.
Small and Catling (1999, 2000 a, and b) have reported on poorly known, potentially economic, plants of Canada, including arctic plants such as muskox or Labrador tea and cloudberry. They include information on historical and possible medicinal uses of plants. The publication by Andre and Fehr (2000) was the result of a project during the summer of 1997 when the staff from the Inuit Research Centre and the Gwich’in Social and Cultural Institute worked with the Gwich’in Elders to document knowledge about the traditional uses of plants. Burt (2000) in her book ‘Barrenland Beauties’, drew on considerable time spent around the Bathurst Inlet region of Nunavut, and included information on the uses of plants by people living in that area. Ootoova et al. (2001) interviewed Inuit Elders on Baffin Island and document perspectives on traditional health including a chapter on ‘Piruqtuit — plants of the land’. Information from these sources is in the database under the heading indigenous knowledge, and additional information is welcomed.
Plants as Monitors of Environmental Change
Random plant collecting and baseline studies
Early expeditions to the Canadian Arctic, such as the Parry Expedition 1819–1820 sampled plants as part of collecting scientific data collecting of the projects (Levere 1993). In the case of the Parry Expedition, approximately 30 type specimens were collected on Melville Island at Winter Harbour. This was probably in the summer of 1820, when the land had ‘warmed’ up and the plants were flowering, while the party waited for the ice to move off the ocean. These type specimens are in a special collection at the British Museum.
Illustration. Left. Parry’s Rock at Winter Harbour, Melville Island. Note the position of the plaque on the left hand side, the tiny yellow poppy flowers in the foreground and the ice still on the bay in the background. It is likely that the many type specimens from Winter Harbour were collected here, while the party was waiting for the ice to move out. Photograph by S. Edlund. Right. The books at the British Museum containing the plants collected on Parry’s voyage. Many of the specimens are the types for the species.
The many ships that searched for the lost Franklin Expedition in the 1850’s also collected plants that were taken back, usually to England. Frans Boas worked in the Cumberland Sound region of Baffin Island in 1883 and 1884 and while his work was mainly anthropological, he did collect some plants (Boas 1885). Much of the Northern part of the archipelago was explored by Norwegians, who were accompanied by people who collected plants. The voyages of the Fram of the Norwegian Arctic Expedition from 1898–1902 made very important collections on Ellesmere and Axel Heiberg Islands (Sverdrup 1903). The Gjøa Expediton lead by Roald Amundsen reached King William Island in 1903 where scientific activities were centered for nearly two years (Amundsen 1908). Many of the plant specimens collected by Norwegians are deposited at the herbarium in Oslo, and are from sites not visited since by Canadian botanists (Simmons, H.G. 1906. Ostenfeld, C.H. 1909). The Canadian Government ship Neptune made extensive voyages under the leadership of geologist A.P Low. Between 1904 and 1911, several cruises were made by the C.G.S. Arctic under Bernier.
Illustration. Bernier’s cabin on Melville Island.
An ardent German collector was Bernhard Hantzsch who collected extensively on Baffin Island from 1909-191l. A major event for botany in the western arctic involved the Canadian Arctic Expedition begun in 1913 and continued until 1918. The report on the botanical findings of this expedition (Holm 1922) makes fascinating reading as a perspective on how much more is now known about many of the species they collected and their taxonomic relationships. Dewey Soper, who was employed by what has become the Canadian Museum of Nature, carried out extensive work on Baffin Island between 1923–1931 (Soper 1981). Many of his plant collections deposited in the herbarium (CAN) are still the only records of a species at most locations in Southern Baffin Island.
The Canadian Museum of Nature Collections division is in the process of entering plant specimen records into an extensive database and from that the list of people who have collected in the N.W.T. Arctic Islands and Nunavut Islands was produced. When this work is completed, the full history of botanical collecting will be easily available. Many of the names on the list are those of people from other disciplines who were in the Arctic and collected plants on the side, for example, W. Blake, R. Christie, C.R. Harrington, and Hattersely-Smith. Prominent botanists who collected in the twentieth century were Aiken, Baldwin, Cody, Consaul, Gillespie, Gillett, Porsild, Polunin and Soreng.
[Link to file Names of Collectors in the Canadian Arctic Archipelago. Not yet available.]
In the twentieth century, there have been baseline and systematic studies done at specific locations. During the Second World War, a military base, ‘Crystal Two’, was set up in the area of what has become Iqaluit, the capital of Nunavut on Baffin Island. In 1948, two researchers from Agriculture Canada, Senn and Calder spent 6 weeks from late June until early August in the area. Among their other projects, they collected about 750 voucher plant specimens, from 149 flowering plant taxa, which were deposited at the Department of Agriculture herbarium, Ottawa. Details on the collection and habitat notes were published as an annotated checklist (Calder 1951).
In 1955, the Geological Survey of Canada research program ‘Operation Franklin’ set out fuel and supplies in early spring with ski-equipped DC-3 aircraft. These widely placed fuel caches across the Arctic Islands supplied helicopter-supported field parties during the summer. The International Geophysical Year (IGY) took place in 1957-58. Lake Hazen in northern Ellesmere Island was chosen as the locale for part of the Canadian contribution to the program. The botanical studies done in connection with this project were reported by Soper and Powell (1985). They found 127 species of flowering plants in the area and collected 3800 specimens, the first set of which was deposited at the Canadian Museum of Nature herbarium, the remaining sets of which were sent to several herbaria in Canada and around the world. Soper and Powell (1985) provide a detailed history of botanical exploration particularly in the eastern Arctic.
Following the productive Operation Franklin and the Canadian International Geophysical Year 1957–58, the Polar Continental Shelf Project was begun and has carried on the work envisioned by Hattersely-Smith (1959). The project made possible the Jacobsen-McGill expeditions that were launched in 1959, to Axel Heiberg Island, particularly in the region of Expedition Fiord. While the primary research program was centered around meteorology, most of the botanical collections from that island have come from researchers who worked from the bases of ‘upper house’ and ‘lower house’ used by that project (Műller 1963). In 1960, The Arctic Institute of North America established a base camp at Cape Spabo, Devon Island. The camp on Truelove Lowlands has been the site of many research projects including the extensive International Biological Programme (IBP) Devon Island project (Bliss 1977).
In 1968, the National Museum of Natural Sciences, (now Canadian Museum of Nature), established the High Arctic Research Station at Polar Bear Pass on Bathurst Island. It has been the base for research in many different disciplines including botany (Brassard and Steere (1968), Brodo (1978), Miller and Ireland (1978), Geale (1980), and Aiken et al. (1995). The specimens from the thesis work by Geale (1980) are deposited at the University of Saskatchewan herbarium. The type location for Festuca edlundae that was distinguished from F. hyperborea in an isozyme study based adjacent to the Polar Bear Pass station.
Between 1979 and 1985, a group of more than 20 people from several Canadian Universities and many different disciplines gathered data at the high polar oasis Alexandra Fiord, Ellesmere Island (78°53′N; 75°55′W) and their findings were published in Svobodo and Freeman (1994). Many of the plant specimens collected were deposited at the University of Toronto herbarium at Erindale.
Plants as Monitors of Anthropogenic Activities
Accidental introductions
In 2002, the finger of suspicion points to the Hudson Bay Company for the introduction of four or more species to the Arctic Islands. Plant seeds were probably introduced in straw used by the company for packing. Freighter canoes arriving from Quebec were packed by placing them on a large piece of sackcloth or hessian, putting straw on the material so the sides of the canoes would be protected, and then wrapping them in the material for shipping (B. Rose, personal communication 2002). There was a significant amount of straw between the boat and the cloth, and seeds may have been introduced in the straw. For the distribution of two species of low Arctic dandelions, the maps in the database indicate that they have been collected at the sites of former Hudson Bay posts. While it may be argued that these are the sites that botanists had access to, in Kimmarut (Lake Harbour) observations by Aiken in 2002 support the suggestion that these plants may have been accidentally introduced.
Dandelions Taraxacumsp. On Baffin Island at Apex, near Iqaluit dandelions are dense behind the beach and on disturbed ground beside the road at the top of the hill in line of sight from the former Hudson Bay Post
Illustration. Dandelions. Taraxacum hyperboreum Dahlst. View of the Hudson Bay Post, Nunavut, Baffin Island, Apex, with dandelions in the foreground. Aiken.
Seeds from the site were deliberately planted in a garden on the eastern side of Iqaluit and dandelion plants have been observed to be spreading across the town from this site (J. Rose, personal communication, 2002). In 2002, two species of dandelions were recorded in the area. One with flowering heads that are a deep yellow and 2.5–3.5 cm in diameter; the other with flowering heads that are a deep orange-yellow, and conspicuously smaller 1.5–2.5 cm in diameter. At Kirramut (Lake Harbour), on 11 July 2002, the centre of the hamlet was yellow with flowering dandelions. Near the hamlet, on disturbed ground suitable for dandelions, such as at the airport, new cemetery, and dump area, there were none. The dandelions in the hamlet were within line of sight of the former Hudson Bay Post that was established there in 1911. In 2002, there appeared to be only one species present, the one with deep yellow flowers 2.5–3.5 cm in diameter. A series of plants with leaf shapes that varied from almost entire to extremely deeply dissected margins were collected to document the variation (Aiken 02-070). Such plants had been collected by Malte in the area in 1929 without comment. Haglund (1943) found the specimens and named two ends of the variation observed, as new species of Taraxacum, citing Lake Harbour as the type location. No reason for maintaining the species names of Haglund was found in 2002 and the identification of the plants as southern species of dandelions is underway. A canoe trip with six days of camping on the tundra beside the Soper River, north of Kimmarut, found only two sites with dandelions in a 60 km trip. One site, at Willow Creek, where willows to 3.9 m occur, is frequently visited by tourists curious to see the trees. A small zone, less than 5 m square with isolated, etiolated dandelions growing up through grass was observed and a voucher specimen was collected. A second site, the landing bay at the end of Soper Lake, had two plants. At both these sites, the dandelions may well have been introduced by human activities. Nowhere else in the 60 km surveyed were dandelions found although they were consciously looked for and suitable disturbed habitats where dandelions might flourish, were observed.
Wild barley Hordeum vulgaris is reported from only one site in the Canadian Arctic Archipelago, and that is in front of the former Hudson Bay Manager’s house in Apex. It is known that one manager in the 1970’s had a goat, which the tethered at this site and fed the packing straw that came up with the freighter canoes. Wild barley is a common weedy species near Montreal where the canoes were made, and it may well have been introduced as seeds in the packing straw.
‘Yukon’ Fireweed Chamerion angustifolium, the territorial flower of the Yukon, is mapped from very few sites on Baffin Island. The Hudson Bay Post was established there in 1921 and the hamlet was active in the 1920’s (Soper 1981) with missionaries coming in from England. ‘Yukon’ fireweed was the first plant to establish on the bombed sites in London after World War 2. The single distribution record of the fireweed on Baffin Island at this site and nowhere else in the islands suggests an accidental introduction possibly in packing material brought in from England.
The orchid Corallorhiza trifida is more difficult to explain. The single distribution record for the islands of an orchid from near Pangnirtung, but from a rather isolated location in the fiord (J. Gould, personal communication 2000). Orchid seeds are very light and are known to be wind borne for long distances and so seeds accidentally arriving at the hamlet of Pangnirtung, may have been blown a considerable distance, or after becoming established, may have formed plants that bore seeds that have traveled on the wind to another site, while the parent plants have been destroyed.
Documented at the Canadian Museum of Nature are single collections of an opium poppy plant less than 15 cm high, collected on the hillside behind Arctic College in 1989 and a weedy member of the mustard family collected at the Causeway in Iqaluit, in 1986. Thus, these alien plants are known to have reached the Arctic islands and to be able to grow for one season but neither of these records has been found in the areas since.
Deliberate introductions
Since the 1980’s, there have been deliberate introductions of Kentucky blue grass and red fescue into Iqaluit, for example in the grounds of Nunavut Arctic College in attempts to establish lawns. Initially the Kentucky blue grass was successful and plants reached heights of 30–45 cm in 1992. After that the plants lost vigour gradually but acted as a nurse crop in the establishment of native species such as the grass Festuca brachyphylla and other early native colonising species with seed sources in the area. Red fescue was observed in Iqaluit in 1986 established on disturbed ground near the Northern Store. In 1992, it was growing well where it had been planted beside the main drive of Nunavut Arctic College, Iqaluit. It was no longer at either site in 2002 as the areas had been dug up during road works. It is suggested that red fescue seed obtained from seed growers that developed the cultivar ‘boreale’ in the Peace River district of Alberta, is more likely to be successful as a ‘lawn’ grass in Iqaluit, than Kentucky blue grass, the seeds of which have been selected from cultivars developed at more southern latitudes.
Garden introductions
Cummins et al. (1988) noted that the Hudson’s Bay company officials insisted that their northern traders make themselves self-sufficient, so gardens were planted at northern posts and forts along the shores of Hudson and James Bays. Agriculture Canada investigated this in a report published by Nowodad, (1963). For many years missionaries in Continental Nunavut tried raising small crops with some success (Moodie 1976). In the 1970’s Government-encouraged greenhouse operations, at Sanikiluaq and Iqaluit, struggled and died. Romer (1987) reported on Pond Inlet gardens, the design and operation of a solar greenhouse on northern Baffin Island. Private greenhouses have existed in Iqaluit for many years.
Cummins et al. (1988) operated two experimental research gardens from 1981-1984 on Continental Nunavut, at Rankin Inlet, (63°N) and on Ellesmere Island at Alexandra Fiord (79°N). They cultivated both native tundra plants and a large assortment of common ‘garden’ vegetables in specially designed, solar-heated greenhouses in a medium of local sand, peat and lake-bottom sediment and found that the resulting crops where
there substantially less expensive than imports and had higher nutritional quality and appeal because of their freshness. They concluded that small-scale food production can be an enjoyable hobby, and has the potential for employment opportunities as well. The frames of the greenhouses used at Alexandra fiord were moved to Eureka and used by people at the Weather station there until a small formal greenhouse was built.
In 1990, three species of plants from the Yukon, latitude approximately 68°N, were deliberately introduced to gardens in Iqaluit 62°N. Twelve small trees 30 cm high, or less, of white spruce (Picea glauca) were offered to people with gardening interests. In 2002, only one of these trees was known to still be alive. It had struggled for several years, but appeared to be doing better from 2000–2002 and with new growth had reached the soaring height of approximately 45 cm. It was growing beside a house in an area covered by snow in winter. A second garden introduction Aconitum delphifolium (a delphinium-like plant with deep blue flowers) came from parent plants about 50 cm high in the Yukon. In Iqaluit the plant reaches about 25–30 cm high most years and flowers. In 12 years a second plant has developed, presumably from seed, in the adjacent enriched, protected, garden soil. Both garden introductions show no tendency to spread to adjacent tundra and would not be expected to be able to compete with native tundra species in the area if the seed did germinate.
About 20 plants of the grass Festuca altaica were introduced from the Yukon in 1990 to an experimental plot in the grounds of Nunavut Arctic College. They have persisted since then and regularly flower, but apparently fail to set seed. They have shown no signs of spreading into adjacent disturbed ground, but look more like being eventually out competed by native tundra species that are becoming established as ‘weeds’ in the experimental garden. This grass can persist on Baffin Island but does not occur naturally there. The species has an unusual distribution in eastern continental North America, with isolated sites in Michigan, Quebec (Table Mountains) and Newfoundland. This may reflect random re-introduction of this predominantly western species to eastern North America after the last glaciation.
[Garden experiments at Eureka. Not yet available.]
With increasing numbers of people visiting or moving to live in the Arctic and with frequent air traffic from the south to previously fairly isolated communities, both more accidental and deliberate introductions of alien plant species to the Canadian Arctic Archipelago can be expected.
Flowers as Arctic Ambassadors
There are territorial flowers for each of the Canadian Arctic Territories: for the Yukon, the fireweed (Chamerion angustifolium); for the Northwest Territories, Mountain Avens (Dryas integrifolia) and for Nunavut there are three arctic flowering plants on the coat of arms. The official flower of Nunavut is the purple saxifrage (Saxifraga oppositifolia), which is one of the first plants to bloom in the spring. The summer flower is the arctic poppy (Papavera sp.) and the fall representative is the crowberry (Empetrum nigrum subsp. hermaphroditum). This plant grows as far North as Ausuittuq (Grise Fiord — the northernmost community) and has several traditional uses. There are about 100 other Arctic plants with showy flowers or berries that contribute to the joys of eco-tourism. These flowers produce colourful displays in whites, yellows, various shades of pinks and purplish pinks and even blues. Conspicuously absent are flowers with vivid red or orange petals. This may be related to the absence of pollinating species that are attracted to these colours. There are nearly 100 other species that have small, often inconspicuous flowers with petals 2–5 mm long and there are over 100 species that have really inconspicuous flowers without petals, including relatively large numbers of grasses, sedges, and willows.
Plants as Climatic Change Indicators
Itex (International Tundra Experiment). The value of plants in monitoring climate is the basis of the ITEX program and network that has attempted to set up experimental sites in the circumpolar tundra regions (Molua, and Molgaard 1996). The goal of ITEX is to understand the response of tundra plant species through simple manipulations and transplant experiments to be conducted at multiple arctic and alpine sites. The objectives are:
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to quantify the change in the environment (i.e. temperature, moisture, and nutrient availability brought about by experimental warming, |
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to quantify the change in the environment from the point of view of the plants by quantifying the shift in phenotypic selection, |
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to understand the potential of tundra plant populations to adjust to climatic warming, either through acclimation or adaptations, and |
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to partition the effect of global warming on key phenological, morphological, and physiological traits into environmental and genetic components. |
Climate change is usually perceived as producing an increase in summer temperatures that will allow an increase in the growth of plants. In the case of Arctic plants, climate change that changes snowfall distribution patterns in the winter may be as significant, or more so, in the development of ‘trees’ in the Arctic islands. In Nunavut, there are two species of willows, which in most areas grow no more than 1 m high, often less. In two localities, they grow as ‘trees’ that are taller than people. On Baffin Island, at Willow Creek, a tributary of the Soper River, Salix planifolia grows more than 3 m tall
Illustration. Tall willows. Salix planifolia Pursh. Willow forest with trees over 3 m high. Nunavut, Baffin Island, Soper River Valley, Willow Creek tributary. Aiken and Isles.
The location is a deep and narrow valley and a sheltered site that may be relatively warmer in summer. Possibly more significant is that the area may fill up with snow drifts in the winter and in doing so protect the plants from abrasive blowing snow that tends to ‘prune’ off new growth in other sites. On Southampton Island, near Sixteen Mile Brook, west of Coral Harbour, Salix alexensis grows tree-like to 2 m high on an exposed hill crest. The area has no distinguishing summer microclimate features to suggest localized enhanced growing conditions, but may well be a place where blowing snow builds up to such levels that the snow bank protects the plants in the winter. Both these willows are represented by many other plants of the same species growing in different microclimates in the adjacent geographic areas where they occur. Such plants are in position to grow more, and survive winter better, if changes in climate that favor summer growth and winter survival occur. If this occurs it should be easily observed. Perhaps it is time to stake significant plants and date growth height, in much the same way as parents keep records of a child’s increasing height.
Grass plants record growing conditions each year in the height that the flowering stems reach. In a good year the stems are tall, and in a bad year they are short. After a winter, the previous season’s stems are often present as straw around the plant after the snow melts the following season. To collect such straw from tagged plants, year after year, would be relatively simple, and the basis of a graph of average stem height against year. Such a graph would be expected to show trends over time if climatic change is occurring.
If dramatic climate change occurred in the Arctic Islands so that temperatures suitable for a growing season for wheat or corn did occur, there are very few places where there is sufficient soil development or summer moisture for such plants to grow. One geologist estimated that it would take 150–200 years for soil formation that would allow significant crop cultivation to occur (L. Lane, personal communication 1990). A candidate crop for growth in the Archipelago, if a longer summer growing season occurs, might be wild rice (Zizania) in shallow tundra ponds that already have a suitable substrate. The plant has been grown with limited success in southern ponds of the Yukon (Aiken et al. 1988).
Citation
Cite this publication as: ‘S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, L.J. Gillespie, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, A.K. Brysting and H. Solstad (1999 onwards). Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 29th April 2003. http://www.mun.ca/biology/delta/arcticf/’. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).