A History of Place: Using Phytolith Analysis to Discern Holocene Vegetation Change on Sanak Island, Western Gulf of Alaska

• Main Author: Wilbur, Cricket C.
• Format: Text
• Language: unknown
• Published: AURA - Antioch University Repository and Archive 2013
• Subjects: paleolimnology; Phytoliths; Phytolith Analysis; Aleutian Islands; Sanak Island; Western Gulf of Alaska. Stomata; Maritime tundra; Monocots; Grasses; Dicotyldons; Arctic ecosystems; Climate change; Paleoenvironmental reconstruction; Holocene; Lake sediment; Bering Land Bridge; Botany; Climate; Environmental Sciences; Geology; Indigenous Studies; Life Sciences; Natural Resources and Conservation; Paleobiology; Paleontology; Plant Biology; Terrestrial and Aquatic Ecology; Arctic; Gulf of Alaska; Archipelago; Tundra; Alaska
• Online Access: https://aura.antioch.edu/etds/89; https://aura.antioch.edu/context/etds/article/1092/viewcontent/Cricket_Wilbur_Dissertation.pdf

This study investigated a terrestrial climate proxy, phytoliths, as a complimentary approach to documenting the dynamics of present and past vegetation on Sanak Island, the largest island in a small island group in the eastern Aleutian archipelago, and as a new basis by which to interpret Holocene environmental variability in Alaska. A phytolith reference collection was established from 59 selected plant species of maritime tundra belonging to 27 families. The grass species and a sedge species produced abundant phytolith forms whereas the majority of dicotyledons in this study were trace producers of phytoliths. A paleoenvironmental reconstruction from fossil phytoliths recovered from a continuous lake sediment core indicates that sedges and cool season grasses were present on this landscape throughout most of the Holocene suggesting the long-term dominance of maritime climate on island vegetation. Adaptation and resilience of the modern vegetation on Sanak Island to a warming climate is suggested by the densities of silicified stomata recovered from six species of grasses, one species of fern, and one species of horsetail when compared to the paleoenvironmental reconstruction. The changes in stomata frequency in the plants on Sanak Island today may have connections to future changes in regional and global climate through the water cycle. Our changing climate is forcing ecosystems to migrate, acclimate or go extinct demonstrating that new insights into ecosystem responses to present and past environmental variation, and forecasting future ecological change are especially relevant today for ecologic and economic sustainability. The electronic version of this Dissertation is at OhioLink EDT Center, www.ohiolink.edu/etd.