Integrated population model to improve knowledge and management of Idaho wolves

Abstract

ABSTRACTRecently, several states in the western United States have assumed management authority of gray wolves (Canis lupus). Wolves pose a challenge for management agencies who must reconcile interests related to conservation of an ecologically important carnivore with management of a dominant predator of ungulates that are highly valued by the hunting public. Thus, managers seek reliable information on the status of wolf populations, the implications of management actions, and the effects of wolf predation on ungulates. We developed an integrated population model (IPM) for wolves in Idaho to assess their status and evaluate the effects of harvest on wolf demographics. We combined pack counts with known‐fate data from global positioning system (GPS)‐collared wolves to obtain estimates of pack size, harvest, non‐harvest mortality, dispersal, and recruitment. Our application emphasizes some of the key benefits of an IPM approach including estimation of parameters for which no direct data are available, the ability to reconstruct pack sizes during periods when count data were missing, and an evaluation of harvest effects on wolf population dynamics. Mean size of wolf packs averaged 5.5 from 2005–2016. There was a general decline in pack size from 2006–2012 with the smallest occurring in 2012, just after the 2011–2012 harvest season. Since 2012, mean pack size has increased, coinciding with a declining trend in the probability of harvest. We found no difference in mid‐year recruitment of wolves into packs during periods with versus without harvest and concluded that harvest mortality is additive to non‐harvest mortality. Thus, harvest may be an effective tool for agencies to manage wolf populations. Although our IPM was informative for wolf management, future monitoring will likely benefit from seeking less costly data sources within an IPM framework. © 2018 The Wildlife Society.