Lead exposure of a fossorial rodent varies with the use of ammunition across the landscape
Exposure to heavy metals has been documented in a wide range of wildlife species, but infrequently in ground squirrels. This is despite their tendency to be targets of recreational shooters and the accumulation of lead ammunition in the soil environments they inhabit. We analyzed lead and copper concentrations in liver (n Pb = 116, n Cu = 101) and femur (n Pb = 116, n Cu = 116) of Piute ground squirrels ( Urocitellus mollis ) and in soil ( n = 75) on public lands in southwestern Idaho to understand how lead exposure may vary across a gradient of intensities and histories of shooting activity. The liver and femur of squirrels from areas used for recreational shooting for greater than 30 years had elevated lead concentrations relative to areas where shooting was rare or did not occur (our negative control), but as expected, lower than areas used for military target training for greater than 70 years (our positive control). Lead concentration in soils were higher in areas used for military target training than in those used for recreational shooting. There were no differences in copper concentrations in biological or soil samples among sites. These data suggest that ground squirrels can be influenced by the history of lead use in their local environment, and they illustrate another pathway by which human activity can influence toxicant exposure to wildlife.