| floristic sectors | |
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Data format: Shapefile File or table name: floristic sectors Theme keywords: Bioclimate subzone, vegetation, map, Image, NDVI, temperature, CAVM |
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Abstract:
Description of Arctic bioclimate subzone categories A-E
As one moves from north to south across the Arctic, the amount of warmth available for plant growth increases. The mean July temperatures are near 0C on the northernmost islands. At these temperatures, plants are at their metabolic limits, and small differences in the total amount of summer warmth make large differences in the amount of energy available for maintenance, growth, and reproduction. Warmer summer temperatures cause the size, horizontal cover, abundance, productivity and variety of plants to increase (see Table 2 CAVM). Woody plants and sedges are absent in Subzone A, where mean July temperatures are less than 3C. Woody plants first occur in Subzone B (mean July temperatures about 3-5 C) as prostrate (creeping) dwarf shrubs, and increase in stature to hemiprostrate dwarf shrubs (<15 cm tall) in Subzone C (mean July temperatures about 5-7C, erect dwarf shrubs (<40 cm tall) in Subzone D (mean July temperature about 7-9C), and low shrubs (40-200 cm tall) in Subzone E (mean July temperature about 9-12C. At treeline, where the mean July temperatures are between 10 and 12C, woody shrubs up to 2 meters tall are abundant. The number of plants in local floras available to form plant communities increases from fewer than 50 species in the coldest parts of the Arctic to as many as 500 species near treeline. |
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Metadata elements shown with blue text are defined in the Federal Geographic Data Committee's (FGDC) Content Standard for Digital Geospatial Metadata (CSDGM). Elements shown with green text are defined in the ESRI Profile of the CSDGM. Elements shown with a green asterisk (*) will be automatically updated by ArcCatalog. ArcCatalog adds hints indicating which FGDC elements are mandatory; these are shown with gray text.
Description of Arctic bioclimate subzone categories A-E As one moves from north to south across the Arctic, the amount of warmth available for plant growth increases. The mean July temperatures are near 0C on the northernmost islands. At these temperatures, plants are at their metabolic limits, and small differences in the total amount of summer warmth make large differences in the amount of energy available for maintenance, growth, and reproduction. Warmer summer temperatures cause the size, horizontal cover, abundance, productivity and variety of plants to increase (see Table 2 CAVM). Woody plants and sedges are absent in Subzone A, where mean July temperatures are less than 3C. Woody plants first occur in Subzone B (mean July temperatures about 3-5 C) as prostrate (creeping) dwarf shrubs, and increase in stature to hemiprostrate dwarf shrubs (<15 cm tall) in Subzone C (mean July temperatures about 5-7C, erect dwarf shrubs (<40 cm tall) in Subzone D (mean July temperature about 7-9C), and low shrubs (40-200 cm tall) in Subzone E (mean July temperature about 9-12C. At treeline, where the mean July temperatures are between 10 and 12C, woody shrubs up to 2 meters tall are abundant. The number of plants in local floras available to form plant communities increases from fewer than 50 species in the coldest parts of the Arctic to as many as 500 species near treeline.
Vegetation greenness is calculated as: NDVI = (NIR - R) / (NIR + R), where NIR is the spectral reflectance in the AVHRR near-infrared channel (0.725-1.1 5, channel 2) where light-reflectance from the plant canopy is dominant, and R is the reflectance in the red channel (0.58 to 0.68 5, channel 1), the portion of the spectrum where chlorophyll absorbs maximally. The resulting image shows the Arctic with minimum snow and cloud cover. The selected pixels were then printed as a false-color CIR image (RGB = ch. 2, ch. 1, ch. 1).
publication date
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Institute of Arctic Biology
University of Alaska Fairbanks
(AVHRR) data were obtained from theUSGS Global AVHRR 10-day composite data. (http://edcdaac.usgs.gov/1KM/1kmhomepage.asp). Glaciers and oceans were masked out using information from the Digital Chart of the World (ESRI 1993).
The map was reviewed by the CAVM mapping team.
Coverage topology was checked using the NODEERRORS and LABELERRORS commands.
complete
Polygon boundaries were overlaid on the false-color infrared basemap and visually inspected.
False-color infrared basemap, NDVI
Digital elevation model
coastline and glacier masks
Initial bioclimate subzone boundaries were taken from the Panarctic Flora (PAF) initiative (Elvebakk et al. 1999, see CAVM for additional references). The boundaries were adjusted by the mappers for individual countries, and then moved to follow existing vegetation polygon boundaries. The vegetation polygons are drawn at a much finer resolution than the bioclimate subzone boundaries, so little information was lost in this process. Most areas are mapped with broad bands of bioclimate subzones, but Svalbard subzones were mapped in more detail, showing the changes that occur from the coast inland, and so that section of the map contains many small subzone polygons.
Canada - PAF boundaries adjusted by W.A. Gould to match data from Edlund (pers.comm.) and personal knowledge. Greenland - Boundaries drawn by F.J.A. Danils. Iceland - all subzone E. Norway - Boundaries drawn by A. Elvebakk. Russia - PAF boundaries modified by B.A. Yurtsev, especially Yakutia and Chukotka. The data from Russia included a sixth subzone (stlanik areas), and subdivided the subzones into mountainous and non-mountainous areas. There are a number of boreal inclusion areas mapped within Chukotka. The boundaries of these polygons are much more detailed than the generalized zonal boundaries in the rest of Russia. United States - PAF boundaries modified in details by D.A. Walker and M.K. Raynolds, mostly along southern edge of Subzone E (see tree line metadata).
Greenland - Boundaries drawn by F.J.A. Danils.
Iceland - all subzone E.
Norway - Boundaries drawn by A. Elvebakk.
Russia - PAF boundaries modified by B.A. Yurtsev, especially Yakutia and Chukotka. The data from Russia included a sixth subzone (stlanik areas), and subdivided the subzones into mountainous and non-mountainous areas. There are a number of boreal inclusion areas mapped within Chukotka. The boundaries of these polygons are much more detailed than the generalized zonal boundaries in the rest of Russia.
United States - PAF boundaries modified in details by D.A. Walker and M.K. Raynolds, mostly along southern edge of Subzone E (see tree line metadata).
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Alaska Goebotany Center
University of Alaska Fairbanks
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Institute of Arctic Biology
University of Alaska Fairbanks