I live-trapped small mammals in forested patches in the Grand Sable Dunes of Pictured Rocks National Lakeshore in 2007 and 2009 to inventory the small mammal species present, to test the predictions of island biogeography theory in a terrestrial landscape, and to identify factors important to habitat selection by deer mice (Peromyscus maniculatus). Species richness was influenced by degree of isolation (F = 5.752, df = 1,11, P = 0.035), but not area or proportion of edge habitat in forested patches. I documented the range expansion of white-footed mice ( P. leucopus) into the Grand Sable Dunes. Deer mice were more likely to be captured in traps without downed woody debris (Wald = 8.461, df = 1, P = 0.004) than with it, but no other characteristics measured at the local scale influenced captures.

Small mammals were trapped in open dune vegetation in the Grand Sable Dunes in 2003 to examine the influence of spotted knapweed (Centaurea stoebe) on the diversity and abundance of small mammals. Nearly twice as many mice (Peromyscus spp.) were captured in spotted-knapweed trapping grids (mean = 0.500 captures/trap, ± 0.312) than in native-vegetation trapping grids (mean = 0.273 captures/ trap, ± 0.192). Small mammal species diversity was low overall (232 of 236 captures were mice) and there was no effect of knapweed on diversity.