Glacial Recession and Freshwater Ecosystems in Coastal Alaska

Abstract

New streams formed after glacial recession provide unique natural sites to study colonization and succession of biotic communities at the scale of entire drainage systems. Site-specific temporal succession has been demonstrated in Wolf Point Creek as changes in dominance of the invertebrate community have been documented and a number of the early Diamesa colonizers are now extinct. Interspecific competition may be an important factor in the elimination of early colonizers in Wolf Point Creek; this inference is presently being tested through field experimentation and manipulation. This study has demonstrated the long time scales for macroinvertebrate colonization where source areas of drift are absent and the difficulty for noninsect taxa to cross mountain and oceanic barriers. An extensive amount of potential new salmonid habitat has been created in coastal Alaska during the last 100 years that has been rapidly colonized by salmonids. Within 30 years, salmonid runs in these new streams may potentially be of sufficient magnitude to contribute to commercial fisheries.