Subarctic forest-tundra vegetation gradients: The sigmoid wave hypothesis

A fossil locality on the Pembina Upland, in southern Manitoba (L. D. Delorme, Geological Association of Canada, Special Paper9, 301–304, 1971), contains three ostracod species near the base of the deposit. Two of these ostracods, Candona rectangulata and Cyclocypris globosa, are found alive only in the northern parts of the Northwest and Yukon territories of Canada. Both species are indicative of subarctic forest tundra and alpine tundra. Their position in the lower 69 cm of the deposit indicates that, as the glacier ice thinned over the upland and retreated from the Lake Agassiz basin, an arctic-subarctic environment could have existed with the potential for tundra vegetation to develop. A reverse situation occurred in the Northwest Territories based on seven fossil ostracod species from a peaty marl deposit. As reported by L. D. Delorme, S. C. Zoltai, and L. L. Kalas. (Canadian Journal of Earth Science14, 2029–2046, 1977) for other similar sites, the striking element is the absence of true arctic ostracods. The majority of the species live very successfully further south in Manitoba and Saskatchewan at present. At both sites, the fossil assemblage is different than the modern assemblage. This indicates a dislocation in space and time which is the basis for the change in paleoenvironmental interpretation.

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Fire-induced changes in soil and vegetation in the forest-tundra of Western Siberia

E3S Web of Conferences ◽

10.1051/e3sconf/202022303001 ◽

2020 ◽

Vol 223 ◽

pp. 03001

Author(s):

Oleg Sizov ◽

Leya Brodt ◽

Andrey Soromotin ◽

Nikolay Prikhodko ◽

Ramona Heim

Keyword(s):

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Western Siberia ◽

The Arctic ◽

Fire Scars ◽

Forest Tundra ◽

The North ◽

Tundra Vegetation ◽

Lichen Cover ◽

The Face

Wildfires are one of the main factors for landscape change in tundra ecosystems. In the absence of external mechanical impacts, tundra plant communities are relatively stable, even in the face of climatic changes. In our study, lichen cover was degraded on burnt tundra sites, which increased the permafrost thaw depth from 100 to 190 cm. In old fire scars (burnt 1980 – 1990) of the forest-tundra, vegetation cover was dominated by trees and shrubs. The soil temperature on burnt forest-tundra sites was higher in comparison to conditions of the unburnt control sites and permafrost was was not found at a depth of 2-2,3m. Dynamics of the Normalized Difference Vegetation index (NDVI) from 1986-2020 reveal that immediately after fires, vegetation recovered and biomass increased due to the development of Betula nana shrubs. In old fire scars of the forest-tundra (burnt 1980-1990), a significant increase in NDVI values was evident, in contrast to the unburnt tundra vegetation where this trend was less pronounced. We conclude that "greening" in the north of Western Siberia may occur due to fire-induced transformation processes. The role of wildfires in the advance of the treeline to the north, driven by climate change and active economic development of the Arctic, will gradually increase in future.

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Tree and Tundra Cover Anomalies in the Subarctic Forest-tundra of Northwestern Canada

ARCTIC ◽

10.14430/arctic1220 ◽

1995 ◽

Vol 48 (1) ◽

Cited By ~ 13

Author(s):

Kevin Timoney

Keyword(s):

Forest Tundra ◽

Subarctic Forest

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Large-scale map of key area in forest-tundra zone on Kola Peninsula: methods of mapping and analysis of result

Geobotanical mapping ◽

10.31111/geobotmap/2013.112 ◽

2013 ◽

pp. 112-124 ◽

Cited By ~ 1

Author(s):

A. R. Loshkareva ◽

N. E. Koroleva

Keyword(s):

Kola Peninsula ◽

Spatial Resolution ◽

Large Scale ◽

Satellite Images ◽

Birch Forest ◽

Mountain Birch ◽

Tundra Zone ◽

Forest Tundra ◽

Tundra Vegetation ◽

Mountain Birch Forest

Large-scale vegetation mapping of key area of 1400 km2 in forest-tundra zone in the middle flow of Teriberkariver (Kola Peninsula) was conducted on the base of satellite images, topographic maps and field geobotanical investigations. Study of Landsat TM images local spectral characteristics and syntaxonomical analysis of vegetation demonstrated that satellite images with 30 m spatial resolution and 6-bands spectral resolution alone can't be used for automatical large-scale classification of forest-tundra zone vegetation. Map of vegetation in scale 1:50 000 resulted from manual processing of both hypsometry and spectral characteristic, on the base of field work points with description of vegetation. Legend of mapped units contains 2 types for tundra, 5 ones for mountain birch forest and 4 ones for wetlands. Quality and correctness of the map were verified by satellite image of extra high spatial resolution Quick Bird (0,65 m/pixel) and aerial photograph for this territory. The map illustrated that distribution of vegetation is primarily caused by unevenness of relief. Timberline lies at 220-240 m a.s.l., altitudinal distances across mountain birch forest and tundra zones are about 40-60 m, tundra vegetation occurs on moraine hills and bedrocks slopes and summits. Pounikkos flark-and-mounds, tuft-and-fen bog complexes occur from 170 to 240 m.s.l. in depressions and valleys. Proportion of tundra vegetation is about 40%, mountain birch forest – 30%, wetlands – 20%, lakes, rivers and springs take 10% of area investigated.

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The Subarctic Forest–Tundra: The Structure of a Biome in a Changing Climate

BioScience ◽

10.1641/0006-3568(2001)051[0709:tsftts]2.0.co;2 ◽

2001 ◽

Vol 51 (9) ◽

pp. 709 ◽

Cited By ~ 113

Author(s):

SERGE PAYETTE ◽

MARIE-JOSÉE FORTIN ◽

ISABELLE GAMACHE

Keyword(s):

Forest Tundra ◽

Changing Climate ◽

Subarctic Forest

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LES ZONES BIOLOGIQUES DE LA PÉNINSULE QUÉBEC–LABRADOR ET L'HÉMIARCTIQUE

Canadian Journal of Botany ◽

10.1139/b52-033 ◽

1952 ◽

Vol 30 (4) ◽

pp. 436-474 ◽

Cited By ~ 23

Author(s):

Par Jacques Rousseau

Keyword(s):

Temperate Zone ◽

The Arctic ◽

Arctic Zone ◽

Tropical Zone ◽

Forest Tundra ◽

Mixed Zone ◽

Absolute Limit ◽

The World ◽

Aquatic Flora ◽

Subarctic Forest

In order to place phytogeographical regions on a world basis, it is necessary to invoke the zone concept. For example, a botanist who studies the flora of some parts of the USSR, Alaska, Quebec, and Scandinavia recognizes many similarities, if not analogous floras: before considering the local differentiations which distinguish regional floras, he recognizes on first sight the "arctic" aspect. The tendency of phytogeographers, foresters, and biologists in general is to overlook the zonal division of the world from the arctic zone to the tropical zone and consider the regional aspects only. In a zonal division of Quebec, there are the temperate zone, grossly south of the 50° lat. N.; the subarctic zone, between the 50° and the 55° approximately; the hemiarctic zone, between the 55° and the absolute limit of trees; and finally the arctic zone, north of the 58°. The hemiarctic zone, described herein, and consisting principally of the habitat commonly called forest–tundra, is not formed of transitional habitats between those of the subarctic zone and those of the arctic zone, but made up of purely arctic patches (from 60 to 90% of the surface) imprisoned in a net of subarctic forest strips. The hemiarctic zone instead of being merely a mixture of arctic and subarctic plants, may be compared then to an "emulsion" of arctic and subarctic habitats. This "mixed" zone, highly convenient for phytogeographical purposes, finds its justification in biological and ciimatological data. For the distinction of the zones, we must not consider only the arborescent flora but all other expressions of life as well. From tentative studies, it is quite evident that a distinction of the zones based on limited floristic aspects,—the aquatic flora for example,—will lead to the same conclusion.

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