Evaluating how lethal management affects poaching of Mexican wolves

Despite illegal killing (poaching) being the major cause of death among large carnivores globally, little is known about effect implementing lethal management policies on poaching. Two opposing hypotheses have been proposed in literature: may decrease poaching incidence (killing for tolerance) or increase it (facilitated killing). Here, we report a test two opposed that (reported and unreported) Mexican grey wolves ( Canis lupus baileyi ) Arizona New Mexico, USA, responded to changes policy reduced protections allow more wolf-killing. We employ advanced biostatistical survival competing risk methods data individual resightings, mortality disappearances collared wolves, supplemented with Bayes factors assess strength evidence. find inconclusive evidence any decreases reported also strong were 121% likely disappear during periods than stricter protections, only slight legal removals by agency. Therefore, support ‘facilitated killing’ hypothesis none ‘killing tolerance’ hypothesis. provide recommendations improving effectiveness US environmental crimes, endangered species wild animals. Our results implications beyond USA because suggest transformations decades-old interventions against human-caused animals subject high rates