Markus Dyck
Samuel A. Iverson
David S. Lee
Nicholas J Lunn
Joseph M Northrup
Marie-Claude Richer
Guillaume Szor
Michael C. Runge
Eric V. Regehr
2021
<div id="abstracts" class="Abstracts u-font-serif"><div id="ab0005" class="abstract author" lang="en"><div id="as0005"><p id="sp0035"><span>Arctic marine mammals are harvested by Indigenous people for subsistence and are socially and culturally important. For ice-dependent species like the polar bear </span><i>Ursus maritimus</i>, management and conservation require understanding interactions between harvest and sea-ice loss due to climate change. We developed a demographic model to evaluate harvest risk for polar bears in Southern Hudson Bay, Canada, where the annual ice-free season has increased by approximately one month in recent decades. The model was based on the theta-logistic equation and allowed for density-dependent changes (through carrying capacity [<i>K</i>]) and density-independent changes (through population growth rate [<i>r</i><span>]). Model parameters were estimated using a Bayesian Monte Carlo method that included capture-recapture, aerial survey, and harvest data. Harvest management followed a state-dependent approach under which new estimates of abundance were used to update the harvest level every five years. Under a middle-of-the-road environmental scenario that assumed </span><i>K</i><span> </span>and<span> </span><i>r</i><span> would decline in proportion to projected sea-ice declines, annual removal of 0.02–0.03 of females resulted in a 0.8 probability of maintaining subpopulation abundance above maximum net productivity level for three polar bear generations (~34 years), our primary criterion for sustainability. Under more pessimistic and optimistic environmental scenarios, comparable female harvest rates were 0.01 and 0.055, respectively. Our coupled modeling-management framework can be used to inform tradeoffs between protection and sustainable use for wildlife populations experiencing habitat loss.</span></p></div></div></div>
application/pdf
10.1016/j.biocon.2021.109128
en
Elsevier
Incorporating climate change in a harvest risk assessment for polar bears Ursus maritimus in Southern Hudson Bay
article