We present an individual-based model of the Norwegian wolf Canis lupus population, which is used to evaluate the effectiveness of current and potential management policies in fulfilling the Norwegian Government's stated aim of maintaining three breeding packs within a designated wolf zone. The model estimates the ‘functional extinction rate’ of the population, defined as the proportion of years in which breeding wolf packs are absent. Under the current conditions according to estimates from Scandinavia, with observed values of natural survival rates (0.903) and unauthorised mortality (0.203) and allowing for immigration from Sweden, the model predicts that the probability of functional extinction is as low as 0.07. This output variable is highly sensitive to the demographic parameters, and if alternative estimates of natural survival rates (0.73 for cubs and 0.83 for adults) reported for wolves elsewhere and higher rates of unauthorised mortality (0.4) are utilised, the functional extinction rate is 0.67 ± 0.15, and the population is dependent on maintenance by immigration from Sweden. The main determinants of the functional extinction rate are the unauthorised mortality rate and the immigration rate from Sweden. The Scandinavian population as a whole shows a rapid non-linear increase in probability of extinction at unauthorised mortality rates >0.10. Varying levels of the current management interventions (increasing the size of the wolf zone and target number of packs) are ineffective; only when the unauthorised mortality rate falls below 0.30 is a self-sustaining population in Norway able to establish. An adaptive harvest policy with culls targeted only at dispersing animals, or taking place only when the population exceeds a threshold level, could be sustainable if the unauthorised mortality rate is reduced. The fact that the Norwegian Government has been explicit about its management strategy and objectives has allowed us to test the ability of this strategy to meet the objectives, and we have shown that it is dependant upon maintaining the current circumstances alongside a high adult survival rate to be able to do so. Given the potentially critical role of the Swedish population in sustaining Norway's wolves, there is a strong case for joint management of the Scandinavian population. These insights are likely to be relevant for the management of other species living across geopolitical boundaries.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.