Document Type
Thesis
Date of Degree Completion
Spring 2024
Degree Name
Master of Science (MS)
Department
Cultural and Environmental Resource Management
Committee Chair
Dr. Megan Walsh
Second Committee Member
Dr. Susan Kaspari
Third Committee Member
Dr. Steven Hackenbeger
Abstract
The Idaho Transportation Department recently contracted archeologists from Eastern Washington University (EWU) to assess potential impacts to cultural resources near McArthur Lake in Bonner County, Idaho, as the result of rerouting U.S. Route 95. The goal of this research is to aid EWU archeologists in their interpretation of the artifacts recovered from the McArthur Lake site by providing them with a local paleoecological reconstruction. Lake sediment-based paleoecological reconstructions provide detailed information on fire history and vegetation change through time and indicate how landscapes responded to past climate variability and human activities. In summer 2022, a sediment core was extracted from Round Lake, which is located in Round Lake State Park, approximately 7 km south of Sandpoint, ID, and 46 km south of the McArthur Lake site. The fire history of Round Lake was reconstructed through macroscopic charcoal analysis and the vegetation history was determined using pollen analysis. The results of this research indicate that the warm and dry early Holocene (ca. 7910-7860 calendar years before present [cal yr BP]) was characterized by an Artemisia-dominated steppe with low/no fire activity. During the middle Holocene (ca. 7830-3220 cal yr BP) more effective moisture became available across the landscape and fire iv activity increased due to higher abundance of burnable biomass. The vegetation present at the site during this time was a mesic mixed-conifer forest dominated by Pinus, Pseudotsuga/Larix, Picea, and Abies, and a riparian forest of Salix, Populus, and Sambucus. The late Holocene (ca. 3220 cal yr BP to present) was the coolest and wettest time period, marked by decreased fire activity and increased abundance of mesic taxa such as Thuja plicata and Tsuga heterophylla. Little to no change was observed in the Round Lake vegetation following EuroAmerican settlement (ca. 100 [1850 CE] to -72 cal yr BP [2022 CE]). In general, fire activity at Round Lake was frequent throughout most of the past 8,000 years. The fire history at Round Lake is indicative of a mixed-severity fire regime throughout much of the Holocene, with the exception of the years during and immediately after the Medieval Climate Anomaly warm period, where a lower proportion of herbaceous charcoal indicates that fires were larger and/or of greater severity. Interestingly, fire activity sharply dropped at the beginning of the Little Ice Age and never returned to the landscape following the termination of the cold, wet period. It is highly probable that the absence of fire during the past ca. 500 cal yr BP was in part a result of the removal of cultural fire regimes from the landscape. Given the frequent, low-moderate severity fire activity at Round Lake throughout much of the past 8,000 years, land managers might want to consider utilizing prescribed burning to reestablish the historic fire regime.
Recommended Citation
Scott, Audrey, "Fire-Vegetation-Climate Interactions: An 8,000- Year Long Paleoecological Reconstruction from Round Lake, Idaho (USA)" (2024). All Master's Theses. 1927.
https://digitalcommons.cwu.edu/etd/1927
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