Use of stable isotope analysis to identify food-conditioned grizzly bears on Alaska's North Slope

Abstract

Abstract Managers often must decide whether to use non-lethal intervention (e.g., hazing or relocation) or lethal removal for resolving bear–human conflicts. Bears with a history of anthropogenic food use are less likely to respond favorably to non-lethal intervention. Stable isotope analysis can be a useful tool to determine a bear's history of anthropogenic food use. We analyzed nitrogen (N) and carbon (C) stable isotopes in 51 hair samples collected between 1991 and 2006 from 30 grizzly bears (Ursus arctos), and their likely food items, from the oilfield region of Alaska's Arctic Coastal Plain (USA) to evaluate the feasibility of using stable isotopes to identify human food use in bears without direct observation. δ15N values varied by >4‰, indicating a trophically diverse diet. We found differences in isotopic values between bears that we had observed on a diet of natural foods (NF) only and those on a predominantly anthropogenic diet (food-conditioned [FC]). For 12 FC and 15 NF bears, mean δ15N value...