Date of Award
12-17-2024
Document Type
Thesis
Abstract
Mean annual temperatures and growing season length have been increasing in northern latitudes. This has impacted permafrost thaw and the water balance of northern regions, resulting in a pattern of drying lakes in the Yukon Flats, Alaska. As lakes dry, they expose lake sediments to colonization by terrestrial vegetation. Recent interest in the terrestrial response to climate change and its effects on ecosystem services led to the formation of the Yukon River Basin project. As a part of this project, we studied plant succession and diversity in the drying lake basins. In the course of our field work we encountered a sedge we believed to be previously undocumented in Alaska. Our documentation of Sartwell’s Sedge, Carex sartwellii, on nine drying lakes during fieldwork in the central Yukon Flats, Alaska, represents a range extension for this species. Previously, its range extended as far northwest as Yukon, Canada, with a reported, but lost collection, from Alaska in 1895. Two earlier collections from the Yukon Flats have been verified; one was misidentified as Carex praegracilis until 2007. Carex sartwellii’s assumed absence from Alaska and Yukon flora, misidentification of an earlier collection, and the remoteness of the Yukon Flats may have contributed to the rarity of its collection. In Alaska this species is morphologically similar to C. praegracilis, but can be distinguished using traits of the perigynia, leaf sheaths, and the production of true vegetative culms. This sedge was found extensively in alkaline drying lake basins, which are similar environments to those found during the Pleistocene. Many of the species that occurred with C. sartwellii in lake basin plant communities have been documented in paleo reconstructions of plants from the Beringian steppe. The Yukon Flats are botanically understudied as a region in Alaska and further research should focus on identifying these unique relict plant communities in the Yukon Flats and their distribution along historic Beringia into Yukon. This would likely lead to more collections of C. sartwellii and expand our knowledge of its distribution and ecology.
Recommended Citation
Winterstein, Mark A., "A range extension for Carex sartwellii in Interior Alaska" (2024). Biological Sciences. 511.
https://ualaska.researchcommons.org/uaf_grad_bio_sciences/511
Handle
http://hdl.handle.net/11122/15694