Quantifying dispersal rates and distances in North American martens: a test of enriched isotope labeling

Pauli, J. N., W. P. Smith, and M. Ben-David

Advances in the application of stable isotopes have allowed the quantitative evaluation of previously cryptic ecological processes. In particular, researchers have utilized the predictable spatial patterning in natural abundance of isotopes to better understand animal dispersal and migration. However, quantifying dispersal via natural abundance alone has proven to be of limited utility for species exhibiting short- or mid-distance dispersal events, including most mammalian species. In previous experimental work, we demonstrated that consumption of 1 dose of isotopically enriched baits elicited a distinct ‘‘mark’’ in hair of captive martens (Martes spp.). Herein, we report findings from a field test of our isotopic enrichment approach to mark freeranging animals and quantify dispersal of martens across forest stands at sites in southeastern Alaska and northern British Columbia. In the field, we supplemented bait used in single-capture hair traps with the amino acid glycine artificially enriched in 2H, 13C, or 15N. By applying unique combinations of artificially enriched isotopic markers within discrete forest stands, the isotopic signature of collected hair reflected the forest patch where the individual originated. From our isotopic marks, we were able to infer dispersal events between forested stands and, thus, estimate rates and approximate dispersal distances. Our findings demonstrate that isotopic enrichment can be a cost-effective method to mark the hair of midsized mammals for the quantification of dispersal.

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Pauli, J. N., W. P. Smith, and M. Ben-David. 2012. Quantifying dispersal rates and distances in North American martens: a test of enriched isotope labeling. Journal of Mammalogy 93(2):390-398.