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Geology topics

James A. Wilson

Publications and source records attributed to James A. Wilson.

2 recordsLinked to original sources

Colonization of southern flying squirrels (Glaucomys volans) to urban Nebraska: Range expansion or human assisted translocation?

Southern flying squirrels ( Glaucomys volans; Linnaeus 1758) were first observed in Lincoln, Nebraska, in 2018, 80 km north of their described range. Given that southern flying squirrels are a species of concern within Nebraska, determining the origin of this new population (natural expansion or pet-trade) garnered interest from state biologists. Further, the recent colonization of Lincoln by southern flying squirrels presents a unique opportunity to investigate the genetic implications of a founding event on a small arboreal mammal. The Lincoln population had genetic characteristics suggestive of a single-event colonization with fewer rare alleles and lower genetic diversity than potential source populations and a high genetic variation between populations. Sample size and absence of other geographically close populations in our data set make it difficult to ascertain the origin of the Lincoln population. Based on shared co-ancestry and membership assignment clustering algorithms, the Lincoln population had greater genetic associations with an individual sampled from the native south-eastern Nebraska population relative to other studied locations, suggesting that Lincoln was colonized by a native population.

Nebraska

Transporting timbers to Chaco Canyon: How heavy, how many carriers and how far/fast?

A total of 200,000+ large timbers were transported >75 km to Chaco Canyon, a political and religious center in the precontact U.S. Southwest, using only human power. Previous researchers reported that typical primary roof beams (vigas) of Chacoan Great Houses averaged 0.22 m in diameter and 5 m in length with a mass of 275 kg. However, the 275 kg mass appears to be a miscalculation. Here, we calculate that a ponderosa pine timber of the stated dimensions would have a mass between 85–140 kg depending on the water content. While still a prodigious load, this recalculated mass requires revisions to estimates of the labor, time, and energy required to build Great Houses at Chaco. Based on contemporary measurements on professional load carriers and soldiers, we estimate that as few as two people could have carried an 85 kg timber across 100 km in as few as 21 h of active walking.

Kiva