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Given the ecological importance of top predators, societies are turning to non-lethal methods for coexistence. Coexistence is challenging when livestock graze within wild predator habitats. We report a randomized, controlled experiment to evaluate low-stress livestock handling (L-SLH), a form of range riding, to deter grizzly (brown) bears, gray wolves, cougars, black bears, and coyotes in Southwestern Alberta. The treatment condition was supervision by two newly hired and trained range riders and an experienced L-SLH-practicing range rider. This treatment was compared against a baseline pseudo-control condition of the experienced range rider working alone. Cattle experienced zero injuries or deaths in either condition. We infer that inexperienced range riders trained and supervised by an experienced rider did not raise or lower the risk to cattle. Also, predators did not shift to the cattle herds protected by fewer range riders. We found a correlation suggesting grizzly bears avoided herds visited more frequently by range riders practicing L-SLH. More research is required to compare different forms of range riding. However, pending experimental evaluation of other designs, we recommend use of L-SLH. We discuss the cobenefits of this husbandry method., Competing Interests: The authors declare there are no competing interests., (©2023 Louchouarn and Treves.)

When humanity confronts the risk of extinction of species, many people invoke precautions, especially in the face of uncertainty. Although precautionary approaches are value judgments, the optimal design and effect of precautions or lack thereof are scientific questions. We investigated Wisconsin gray wolves Canis lupus facing a second wolf-hunt in November 2021 and use three legal thresholds as the societal value judgments about precautions: (1) the 1999 population goal, 350 wolves, (2) the threshold for statutory listing under the state threatened and endangered species act, 250 wolves; and (3) state extirpation <2 wolves. This allows us to explore the quantitative relationship between precaution and uncertainty. Working from estimates of the size wolf population in April 2021 and reproduction to November, we constructed a simple linear model with uninformative priors for the period April 2021-April 2022 including an uncertain wolf-hunt in November 2021. Our first result is that the state government under-counted wolf deaths in the year preceding both wolf-hunts. We recommend better scientific analysis be used when setting wolf-hunt quotas. We find official recommendations for a quota for the November 2021 wolf-hunt risk undesirable outcomes. Even a quota of zero has a 13% chance of crossing threshold 1. Therefore, a zero death toll would be precautionary. Proponents for high quotas bear the burden of proof that their estimates are accurate, precise, and reproducible. We discuss why our approach is transferable to non-wolves. We show how scientists have the tools and concepts for quantifying and explaining the probabilities of crossing thresholds set by laws or other social norms. We recommend that scientists grapple with data gaps by explaining what the uncertainty means for policy and the public including the consequences of being wrong., Competing Interests: The authors declare no financial competing interests. AT discloses the following non-financial, potential competing interests. Professional service to organizations or editorial boards Board of director (unpaid): President, Future Wildlife (2020), Board member Wildlife for All (Sep. 2021-present) Science advisor (unpaid): Project Coyote (2012–) Northeast Wolf Coalition (2014–) Endangered Species Coalition (2016–) Friends of the Wisconsin Wolf (2015–) Living with Wolves (2016–) Rocky Mountain Wolf Coalition (2018–2021) Earth and Animal Advocates (2019–) Benton County’s Agriculture and Wildlife Protection Program (2018–) Wild Earth Guardians (2020–) Member (unpaid): Union of Concerned Scientists (2015–), IUCN Bear Specialist Group task-force on human-bear conflicts (2012), IUCN Wolf specialist (2016–), Public Employees for Environmental Responsibility (2015–2019). Expert declarations (unpaid): Wi Federated Humane Societies et al. v Stepp. 2013. WI Court of Appeals District IV; WEG v Colorado Parks and Wildlife Commission et al. 2017. District Court, Denver Country, Colorado; Western Watersheds Project et al. v USDA Wildlife Services. 2018. U.S. District Court for the District of Idaho 1:17-cv-00206-BLW Doc 22-3; CBD & Cascadia Wildlands v WDFW 2018. Superior Court of Washington for Thurston County. 18-2-04130-34. CBD v WDFW et al. 2019. Superior Court of Washington for Thurston County, 18-2-02766-34. Huskin et al. v WDFW et al. 2019. Superior Court of Washington for King County 19-2-20227-1 SEA. Great Lakes Wildlife Alliance et al. v. Cole et al. Circuit Court Dane County, Wi 2021cv002103 Branch 9 Circuit Court Summons Dane County, WI, Case 2021CV002103 Document 5 Filed 08-31-2021 Paid service as external reviewer or speaker: Swiss-NSF SPARK (2019), Antioch University of New England (2018–2020), Landmark Foundation (2017), various publishers (2007–2017), U.S. Fish & Wildlife Service (2019), French Ministry of Environment, Scientific Council on Wolves (208-present), Ministry of Environment, Alfred Toepfer Academy for Nature Conservation, Lower Saxony, Germany (2021-present), NABU, Germany (2015, 2021) This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Despite illegal killing (poaching) being the major cause of death among large carnivores globally, little is known about the effect of implementing lethal management policies on poaching. Two opposing hypotheses have been proposed in the literature: implementing lethal management may decrease poaching incidence (killing for tolerance) or increase it (facilitated illegal killing). Here, we report a test of the two opposed hypotheses that poaching (reported and unreported) of Mexican grey wolves ( Canis lupus baileyi ) in Arizona and New Mexico, USA, responded to changes in policy that reduced protections to allow more wolf-killing. We employ advanced biostatistical survival and competing risk methods to data on individual resightings, mortality and disappearances of collared Mexican wolves, supplemented with Bayes factors to assess the strength of evidence. We find inconclusive evidence for any decreases in reported poaching. We also find strong evidence that Mexican wolves were 121% more likely to disappear during periods of reduced protections than during periods of stricter protections, with only slight changes in legal removals by the agency. Therefore, we find strong support for the 'facilitated illegal killing' hypothesis and none for the 'killing for tolerance' hypothesis. We provide recommendations for improving the effectiveness of US policy on environmental crimes, endangered species and protections for wild animals. Our results have implications beyond the USA or wolves because the results suggest transformations of decades-old management interventions against human-caused mortality among wild animals subject to high rates of poaching., (© 2021 The Authors.)