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For 90 years, the American Society of Mammalogists (ASM) has made science-based challenges to widespread lethal control of native mammals, particularly by the United States federal government targeting carnivores in the western states. A consensus is emerging among ecologists that extirpated, depleted, and destabilized populations of large predators are negatively affecting the biodiversity and resilience of ecosystems. This Special Feature developed from a thematic session on predator control at ASM's 2013 annual meeting, and in it we present data and arguments from the perspectives of ecology, wildlife biology and management, social science, ethics, and law and policy showing that nonlethal methods of preventing depredation of livestock by large carnivores may be more effective, more defensible on ecological, legal, and wildlife-policy grounds, and more tolerated by society than lethal methods, and that total mortality rates for a large carnivore may be driven higher than previously assumed by human causes that are often underestimated.

From 2006 to 2017, stray or free-roaming cats ranged from 35 to 54% of all animals going into the public shelter in Hillsborough County, Florida. Shelter overcrowding of cats, including free-roaming, feral, or community cats, is a major problem in parts of the world. Issues with free-roaming cats include the welfare of the cats themselves, public health and zoonotic diseases, spread of diseases to other species or pet cats, public nuisance, and predation of wildlife. Animal control is a government function and ultimately a taxpayer issue. This paper describes three methods of humane, nonlethal management of free-roaming cat populations that were successfully applied in Hillsborough County, Florida: low-income spay/neuter vouchers; small- and large-scale trap, neuter, vaccinate, and return (TNVR); and return to field (RTF). The methods used were contrary to the long-accepted practice of using euthanasia to control cat populations and generated opposition among certain stakeholders. While the human population of the county increased by 14.6% from 2010 to 2017, the methods used to control free-roaming cats assisted in achieving a 51% decrease in intake since 2007 and increased the live-release rate to 81.8% of cats taken in at the Pet Resources Center in 2017. This paper examines how this change in intake was achieved despite opposition to these programs.

We tested the effect of the native container-dwelling predator Toxorhynchites rutilus on the codominant container-dwelling mosquitoes: native Aedes triseriatus and invasive Aedes japonicus. We established two predator treatments (predator, no predator) by removing T. rutilus from all containers, and stocking T. rutilus larvae (1/3.5 liters) in the predator treatment. Removal and stocking was repeated every 3 d and established significantly different predator abundances in both large and small containers. Repeated-measures analysis of variance (ANOVA) on standard samples showed larvae+pupae/liter of A. japonicus was greater without versus with predation, and this difference increased across samples. In contrast, repeated-measures ANOVA showed larvae+pupae/liter of A. triseriatus was statistically indistinguishable for predation treatments and was greater in small versus large containers.Thus, predation reduced invasive A. japonicus while having no detectable effect on A. triseriatus larvae and pupae. A final destructive census of pupae showed that predation reduced pupae/liter of both species, but this effect was greater and more consistent across container sizes for A. japonicus. Predator effects on abundances were not products of the nonlethal effect of predator avoidance by ovipositing females, as T. rutilus presence did not lead to reduced egg inputs by either Aedes, nor by Aedes spp. as a group. Effects of predation thus are best explained by differential success of developing larvae due to the greater lethal effect of T. rutilus on A. japonicus than on A. triseriatus.Thus, this system is consistent with the hypothesis that native predators can limit success and potential impacts of invasive mosquitoes.

ObjectiveTo examine how escalation through the force continuum predicts officer injury in the presence of citizen aggression, while controlling for extraneous factors, like citizen and officer characteristics.MethodsCross-sectional data were extracted from 2244 use-of-force reports from the Dallas Police Department in 2015. Multilevel, mixed logistic regression models were used to evaluate the relationship between use of force and officer injury. Multilevel path analysis tested indirect and direct relationships between citizen aggression and officer injury.ResultsResults suggest that gradual escalation through the force continuum significantly decreases officer injury when a citizen is actively aggressive (β=−1.06, p value <0.001). Further, non-Hispanic black officers (β=−0.22, p value <0.001) and Hispanic officers (β=−0.08, p value <0.05) are less likely to gradually escalate through the force continuum, due to lower odds of verbal commands (black: OR=0.51, 95% CI 0.39 to 0.68; Hispanic: OR=0.77, 95% CI 0.60 to 0.99) and hard-empty hand control (black: OR=0.58, 95% CI 0.43 to 0.77) compared with white officers. Finally, officers with higher tenure (β=−0.01, p value <0.001) are less likely to gradually escalate through the force continuum.ConclusionsEscalation through the force continuum significantly reduces police officer injury. Future research should assess whether further environmental or situational factors contribute to the strong relationship between use of force and officer injury. Also, reliability and validity testing of use-of-force reports is an imperative direction for future research.

Predation by wild carnivores challenges livestock producers worldwide. To reduce or offset losses due to predation, a variety of predator control methods and compensation schemes have been developed. In 2001, Marin County, California, USA replaced its U.S. Department of Agriculture Wildlife Services (WS) cooperative predator damage management program with a county-run program that emphasized nonlethal methods for preventing and controlling coyote (Canis latrans) predation on domestic sheep (Ovis aries). This new Livestock Protection Program (LPP) cost-shared with livestock producers’ efforts to improve fencing, obtain and maintain guard animals, and other such nonlethal methods, and initially it compensated producers for documented losses to predators. In 2006, 5 years into the program, 17 sheep producers were surveyed to compare the former WS program to the LPP with regard to rancher satisfaction and preferences, lethality to predators, livestock losses, uses of nonlethal predator deterrent techniques, and costs. In 2016, 15 years after the program was replaced by a county-administered nonlethal program, we surveyed sheep producers to determine if their perceptions of the program had changed. Although the lack of standardized data collection complicated our evaluation, the number of sheep and lambs produced in Marin County has continued to decline; 5 producers left the sheep business and others who remain graze less acreage with smaller flocks, predation by coyotes remains a high concern to producers, and producers are generally dissatisfied with the Livestock Protection Program. Recommendations include increased programmatic funding for management practices, payments for losses, and seasonal hiring of wildlife specialists during critical times, especially during lambing seasons.

Sterilization is an effective nonlethal tool to reduce livestock depredation by coyotes (Canis latrans) because adults without pups to provision are less likely to kill livestock. Surgical sterilization is costly and invasive, so identifying nonsurgical methods for canids that allow wide-scale application is important. We conducted a preliminary assessment of 2 types of reproductive inhibitors (gonadotropin releasing hormone [GnRH] vaccine and deslorelin, a GnRH agonist) on coyote reproductive capabilities. We treated captive coyotes with a GnRH vaccine (n = 6 males, n = 6 females) or deslorelin (n = 6 males), measured number of litters and pups born, and compared their behavior and hormone levels to captive coyote pairs in which the male was surgically vasectomized (n = 6). At least half of the pairs receiving treatment with either of the nonsurgical reproductive inhibitors produced pups, and litter size was larger than expected compared to historical records. Male coyotes treated with deslorelin showed decreased testosterone levels, whereas there was no difference in testosterone levels in males treated with GnRH vaccine compared to controls. Behavior did not differ between any groups. Despite the lack of efficacy of either reproductive inhibitor tested, our research suggests that hormonal alterations that disrupt reproduction of coyotes are unlikely to negatively affect behavior, and further investigation of nonsurgical reproductive inhibitors for wild canids is warranted.

We examined the relationship between muscle and scale mercury (Hg) and lead (Pb) concentrations in chub Squalius cephalus L. from six riverine sites in the Czech Republic in order to determine whether scale analysis alone could provide a nonlethal and convenient method for prediction of heavy metal concentration in muscle tissue. Our results confirm tissue-specific heavy metal accumulation in chub, with Hg tending to accumulate primarily in muscle tissue and Pb in scales. We found no significant relationship, however, for concentrations of either Pb or Hg between muscle tissue and scales of chub. Our results indicate that scales cannot be used for predicting heavy metal contamination in muscle of chub and we recommend, therefore, that muscle biopsy methods continue as the preferred method of analysis.

Methyl mercury cation (MeHg⁺) and divalent mercury (Hg²⁺) were quantified in urine, liver, kidney, and brain of prairie voles (Microtus ochrogaster) during a 12 week exposure to aqueous MeHg⁺ at concentrations of 10, 100, and 1000 ng MeHg⁺/mL. Aqueous MeHg⁺ exposures increased mercury accumulation in tissues of voles from each exposure group. Accumulation was greater within the higher two exposure groups. Similar [Hg²⁺] and [MeHg⁺] were determined within a given organ type before and after 2,3-dimercapto-1-propane sulfonate (DMPS) chelation. Similar correlations were seen for Hg²⁺ and MeHg⁺ concentrations in pre and post chelation urine. Post chelation urine more reliably predicted mercury species concentrations in tissues than did urine collected before chelation. These data demonstrate the utility of DMPS in noninvasive assessment of wildlife exposure to mercury, which may have utility in evaluating meta-population level exposure to hazardous wastes.

Lethal control alone has not proven entirely effective in reducing gray wolf (Canis lupus) depredations in chronic problem areas. Opponents of lethal control argue that more emphasis should be placed on integrating nonlethal strategies into current management. However, few evaluations have tested the effectiveness of nonlethal options. We compared behavior patterns in terms of frequency and duration of bait station visits for 5 wolves fitted with shock collars to 5 control animals inhabiting wolf pack territories in northern Wisconsin during summers of 2003 and 2004. Shock collared wolves spent less time and made fewer visits to bait station zones than did control animals. During and after shocking, wolves shifted 0.7 km away from the bait station zone. Although active shocking did restrict wolf access, which could be useful in controlling wolf depredations during a limited time period, conditioning was not clearly demonstrated once shocking ceased. The effect of shock collar design and operation on long-term conditioning and shock-conditioned wolves on pack behavior needs further study. If long-term conditioning is possible, shock collars could be used by wildlife managers as a nonlethal wolf management method in chronic problem areas where lethal control has proven ineffective.

Wild mammals cause foraging damage to crops worldwide and nonlethal methods are required for controlling such damage. Many wildlife management situations demand protection of untreated foods. We tested learned food aversion plus an odor cue as a paradigm for protecting untreated model crop items from European badgers (Meles meles). Following conditioning with a combination of ziram and clove oil, badgers avoided untreated maize cobs in presence of a clove odor cue. A clove oil control did not condition badgers. This work has been an important step before proceeding to full-scale field trials for protecting growing crops on a wider scale.