Date of Award
H. Thomas Goodwin
We performed stable isotope analyses of fecal pellets to investigate temporal and spatial patterns in the diet of free-ranging, thirteen-lined ground squirrels (Ictidomys tridecemlineatus). Samples were collected opportunistically from a population in SW Michigan from May to September 2012. We found a statistically significant increases in d13C values throughout the study period, possibly correlating to a late-season flush of C-4 plants. Also, samples collected within 25 m of a cornfield had a mean d13C value of -20.470%, a value significantly higher than those outside the 25 m border (mean=26.192%). This patternmay be indicative of a C-4 rich diet probably due to increased corn consumption. Similarly, we found that the d15N values of pellets collected near the cornfield were also significantly higher (mean of 3.229%) than those further away (mean=1.765%). This may imply increased animal/insect consumption, or, more likely, is an artifact of artificial fertilizers.
Chacko, Allie, "Spatial and Seasonal Variation in the Stable Isotopic Composition of Thirteen-lined Ground Squirrel Fecal Pellets as an Estimate of Variation in Diet" (2013). Honors Theses. 59.
Thirteen-lined ground squirrel, Ground squirrels--Feces., Animal droppings--Analysis.
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