Summit to sea: Terrestrial, coastal & freshwater habitats of Southeast Alaska Here’s the first 11 pages of a 150-page draft…2018 draft | Richard Carstensen | 11 page excerpt
Terrestrial habitats has 3 subcategories: Forests, Wetlands, and High country. Explore those sub-categories or find general information on Terrestrial Habitats below. You can also view the entire JuneauNature hierarchy at this site map.
Distinctions between terrestrial and aquatic get a little fuzzy on the rain coast. Here’s how we introduced the Habitats section of Nature of SE AK, 3rd edition.
“Amount and distribution of water is the logical way to differentiate Southeast’s many [terrestrial] habitats. These range from ocean, lakes, ponds, and rivers, to frequently submerged salt marshes and stream flood zones, to perennially saturated bogs and other freshwater wetlands, to the usually drenched rain forest and alpine tundra. After a rare two-week drought, it’s sometimes possible to sit in the forest understory without soaking our pants. Then rain resumes.
Some habitats are defined by solidified water—glaciers and high-country snowfields. The term “terrestrial” as applied to certain Southeast Alaskan habitats is somewhat generous; it actually means “occasionally free of water.” Carstensen, Armstrong & O’Clair (2014)
The primary control on terrestrial habitat is drainage or substrate permeability. In rainy Southeast, where waterlogged soils prevail, soil drainage is a key determinant of habitat type. Among terrestrial habitats, well-drained surfaces typically support forest, or pre-forest successional stages, while poorly drained surfaces support nonforested or sparsely forested wetlands.
In addition to drainage, other primary influences on terrestrial habitat diversity includ successional age—or time since last substantial vegetation disturbance—and elevation above sea level. Collectively, these 3 primary factors exert control over habitat character throughout Southeast and are clearly expressed on virtually every site.
Secondary influences, such as aspect, climate, bedrock geology, and other living things (biotic influences) are locally important but most evident in more extreme situations. For a review of primary and secondary controls on habitat, check out this excerpt from my draft of Summit to sea.