Poaching regulates the legally hunted wolf population in Finland

Abstract

Poaching may threaten population viability and can occur in both non-harvested and legally harvested populations. Telemetry facilitates the determination of the fates of individual animals, and the resultant mortality scenarios can be used to evaluate the role of poaching in population changes. Finland's legally hunted wolf (Canis lupus) population fluctuated between 100 and 300 animals during 1998–2016, and this cannot be explained by the rates of legal hunting and other known mortalities alone. We examined the role of poaching in wolf population changes. We created different scenarios based on multi-source information on poaching among 130 collared wolves. Poaching has been the primary cause of death followed by legal hunting. We calculated thesurvival rate and cause-specific mortality risk; wolves whose fates were unknown were censored. As one of the event alternatives (unknown fate or known mortality cause), censoring was related to social status; breeding adults were more often poached, whereas dispersers were censored. We created two sets of scenarios based on the censoring procedure (random and non-random), and for both sets, we created 4 scenarios ranging from high to no poaching based on decreasing confidence in the data. Annual survival ranged from 0.11–0.24 (high poaching scenario) to 0.43–0.60 (no poaching); survival dropped in mid-winter. The poaching rate varied between years from less than 0.09–0.13 up to 0.31–0.43. We consider poaching to be a regulatory factor; it focused on breeding adults and seemed to escalate as a response to increased population size. We conclude that tolerance for carnivores cannot be promoted by legal hunting alone, so more comprehensive conservation efforts are needed.