Alaska Arctic Tundra Vegetation Map

Substrate Chemistry

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This map is nearly identical to the Alaska portion of the Substrate Chemistry map of the Circumpolar Arctic Vegetation Map. Only the boundaries of the map and scale are changed.

Differences in substrate chemistry, including pH, govern the availability of essential plant nutrients. Soils in the circumneutral range (pH 5.5-7.2) are generally mineral rich, whereas the full suite of essential nutrients is often unavailable in acidic soils (pH < 5.5) or in soils associated with calcareous bedrock (pH > 7.2). The latter often have unique assemblages of plant species. The substrate chemistry map is derived from a wide variety of sources including soil, surficial geology and bedrock geology maps, and from spectral patterns that could be recognized on the AVHRR base image. Vegetation types are listed by substrate type. Carbonate and circumneutral substrates were combined to simplify the table. Carbonate substrates occur mostly in mountainous regions, while circumneutral substrates are mostly fine-grained loess occurring at lower elevations in foothills or plains.