SEAN Ecological Subsections

The purpose of this ecological unit map is to aid sampling for inventory and monitoring studies in Glacier Bay NP&Pres., Klodike Gold Rush NHP, and Sitka NHP, Alaska. There has been increasing interest in inventory and monitoring of natural resources in National Parks, Monuments, and Preserves in Alaska. However, the choice of where to sample is difficult due to the large area involved. One useful strategy is to stratify sampling by ecosystem regions, to ensure adequate coverage of all ecosystems and economical allocation of the sampling effort. A hierarchical classification for subsections was created to reflect developmental histories of terrestrial surfaces of Southeast Alaska (Table 2). Three terrain classes were distinguished at the first level. Subsections currently affected by glacial processes (ice accumulation and movement, meltwater streams with heavy bedloads, deglaciated areas of primary succession) were classified as active glacial terrains. Older surfaces developing after the retreat of continental ice (=14,000 years ago) fell into the inactive glacial terrain class. The majority of subsections occurred in this category. Subsections resulting from post-glacial processes not related to glaciation (i.e., volcanism) were classified as post-glacial terrains. These three classes were then divided by physiography. This second level was further subdivided by lithology and surficial geology (referred to as geologic classes) to form a third hierarchical tier.

SEAN Ecological Subsections

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