Succession   at   Glacier  Bay,
   Alaska.

   Plant  species  composition  changes dramatically during succession at
   Glacier Bay, accompanied by changes in abiotic factors.

   Pioneering  species  such as liverworts, mosses, and fireweed build up
   the soil.

   Nitrogen  fixation  by  Dryas  and Alder enrich the soil, leading to a
   sprucehemlock climax forest.