Recent citizen deaths involving police use of force have increased discussion surrounding police accountability and community relations. One piece of this discussion is the use of body worn cameras ...(BWCs) by officers. Unfortunately, little rigorous research has been conducted to estimate the effectiveness of BWCs in reducing problematic police-citizen interactions. In this paper, we estimate two measures of effectiveness of BWCs by comparing incidents that occur in a squad assigned cameras to incidents that occur in a squad assigned control. First, we estimate the effect of being assigned a BWC (but not necessarily using the camera) on reducing complaints and resistance associated with incidents. Second, we employ data on BWC use to estimate the effect of cameras if they were used with full compliance. Together, these two estimates provide a plausible range of effectiveness that policymakers can expect from BWCs. We find that BWCs have no effect on the rate of arrest or resistance, but can substantially reduce complaints.
Artificial nightlight is increasingly recognized as an important environmental disturbance that influences the habitats and fitness of numerous species. However, its effects on wide‐ranging ...vertebrates and their interactions remain unclear. Light pollution has the potential to amplify land‐use change, and as such, answering the question of how this sensory stimulant affects behavior and habitat use of species valued for their ecological roles and economic impacts is critical for conservation and land‐use planning. Here, we combined satellite‐derived estimates of light pollution, with GPS‐data from cougars Puma concolor (n = 56), mule deer Odocoileus hemionus (n = 263) and locations of cougar‐killed deer (n = 1562 carcasses), to assess the effects of light exposure on mammal behavior and predator–prey relationships across wildland–urban gradients in the southwestern United States. Our results indicate that deer used the anthropogenic environments to access forage and were more active at night than their wildland conspecifics. Despite higher nightlight levels, cougars killed deer at the wildland–urban interface, but hunted them in the relatively darkest locations. Light had the greatest effect of all covariates on where cougars killed deer at the wildland–urban interface. Both species exhibited functional responses to light pollution at fine scales; individual cougars and deer with less light exposure increasingly avoided illuminated areas when exposed to greater radiance, whereas deer living in the wildland–urban interface selected elevated light levels. We conclude that integrating estimates of light pollution into ecological studies provides crucial insights into how the dynamic human footprint can alter animal behavior and ecosystem function across spatial scales.
Climate and land‐use change are the major drivers of global biodiversity loss. Their effects are particularly acute for wide‐ranging consumers, but little is known about how these factors interact to ...affect the abundance of large carnivores and their herbivore prey. We analyzed population densities of a primary and secondary consumer (mule deer, Odocoileus hemionus, and mountain lion, Puma concolor) across a climatic gradient in western North America by combining satellite‐based maps of plant productivity with estimates of animal abundance and foraging area derived from Global Positioning Systems telemetry data (GPS). Mule deer density exhibited a positive, linear relationship with plant productivity (r2 = 0.58), varying by a factor of 18 across the climate‐vegetation gradient (range: 38–697 individuals/100 km2). Mountain lion home range size decreased in response to increasing primary productivity and consequent changes in the abundance of their herbivore prey (range: 20–450 km2). This pattern resulted in a strong, positive association between plant productivity and mountain lion density (r2 = 0.67). Despite varying densities, the ratio of prey to predator remained constant across the climatic gradient (mean ± SE = 363 ± 29 mule deer/mountain lion), suggesting that the determinacy of the effect of primary productivity on consumer density was conserved across trophic levels. As droughts and longer term climate changes reduce the suitability of marginal habitats, consumer home ranges will expand in order for individuals to meet basic nutritional requirements. These changes portend decreases in the abundance of large‐bodied, wide‐ranging wildlife through climatically driven reductions in carrying capacity, as well as increased human–wildlife interactions stemming from anthropogenic land use and habitat fragmentation.
Changes in the abundance and distribution of wildlife species have economic consequences in terms of recreation, tourism, and agricultural damage. However, large, migratory species such as mule deer and mountain lions are difficult and expensive to enumerate and monitor. We used satellite imagery to model population densities of these species across a climatic gradient in western North America. Both species demonstrated highly predictable patterns in abundance with changes in plant productivity. These relationships can be used to predict changes in species abundance and distribution under differing climate and land‐use forecasts for western North America.
Forage availability and predation risk interact to affect habitat use of ungulates across many biomes. Within sky‐island habitats of the Mojave Desert, increased availability of diverse forage and ...cover may provide ungulates with unique opportunities to extend nutrient uptake and/or to mitigate predation risk. We addressed whether habitat use and foraging patterns of female mule deer (Odocoileus hemionus) responded to normalized difference vegetation index (NDVI), NDVI rate of change (green‐up), or the occurrence of cougars (Puma concolor). Female mule deer used available green‐up primarily in spring, although growing vegetation was available during other seasons. Mule deer and cougar shared similar habitat all year, and our models indicated cougars had a consistent, negative effect on mule deer access to growing vegetation, particularly in summer when cougar occurrence became concentrated at higher elevations. A seemingly late parturition date coincided with diminishing NDVI during the lactation period. Sky‐island populations, rarely studied, provide the opportunity to determine how mule deer respond to growing foliage along steep elevation and vegetation gradients when trapped with their predators and seasonally limited by aridity. Our findings indicate that fear of predation may restrict access to the forage resources found in sky islands.
Sky‐island populations, rarely studied, provide the opportunity to determine how mule deer respond to greening foliage along steep elevation and vegetation gradients when trapped with their predators and seasonally limited by aridity. We use novel methodology to ascertain these responses. Our findings indicate that fear of predation restricts access to the forage resources found in sky islands.
Although rates of illicit drug use in the United States have remained stable within the last decade, the age-of-onset for drug use is decreasing for certain substances, and the United States still ...accounts for the highest rates of overall drug use. In a recent national sample, an estimated 19.8 million users ages 12 years and older were identified. Preventative efforts that target adolescents often neglect to consider differences among racial/ethnic groups. Applying the Social Development Model (SDM), the current study examines the likelihood of drug use among Hispanic youth. Self-reported data (n = 37,445) from a statewide, school-based sample collected in 2008 are used. Results suggest that the SDM is a promising framework for assessing Hispanic youths’ likelihood of engaging in illicit drug use.
Cougar Dispersal and Natal Homing in a Desert Environment Choate, David M.; Longshore, Kathleen M.; Thompson, Daniel B.
Western North American naturalist,
2018-August, 20180801, 2018-08-00, Letnik:
78, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We present a review of cougar dispersal literature and the first evidence of natural (i.e., unmanipulated) homing behavior by a dispersing male cougar (Puma concolor) that sustained severe injuries ...crossing the northern Mojave Desert. Based on Global Positioning System and ground tracking data, the male traveled a total distance of 981.1 km at 5.03 km/d, including 170.31 km from the Desert National Wildlife Refuge to the northwestern Grand Canyon, where he sustained severe injuries. The interkill interval increased from 7.1 ± 2.7 d while he was in his natal range to 17.5 ± 4.9 d during dispersal. While homing, the male appeared to consume only reptiles until he died, 33.7 km from his capture site. In desert environments where prey availability is low, homing behavior may be an important strategy for dispersing cougars, providing a mechanism for persistence when the best quality habitats they encounter are already occupied by adult residents. Therefore, managing for habitat connectivity can ensure successful homing as well as dispersal on a greater scale than has been previously suggested. Elucidating the mechanisms that trigger homing during dispersal may provide critical insight into animal movements often overlooked as mundane behavior.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The Phoenix TRUCE Project was modeled after the Chicago CeaseFire program. There have been relatively few process and impact evaluations on the model compared to the level of funding and attention ...the program has rendered. This paper presents findings related to the evaluation of the TRUCE project. We found that the program engaged in a strong media campaign, conducted conflict mediations, and identified high-risk individuals for case management. The program did not, however, establish a coordinated and collaborative relationship with the faith-based community or other community groups. Time-series analysis showed that program implementation corresponded to a significant decrease in overall levels of violence by more than 16 incidents on average per month, a decrease of 16 assaults on average per month, and resulted in a significant increase of 3.2 shootings on average per month, controlling for the comparison areas and the trends in the data.
Limited research attention has focused on homicides involving foreign-born victims. Using data from the National Violent Death Reporting System, we examined 9428 homicides that occurred in 2017 in ...the United States across 32 states and D.C. Approximately 8% of homicide victims were foreign-born. Homicide victimization rates were substantially lower for foreign-born persons, compared to U.S.-born persons. However, foreign-born persons from Honduras, El Salvador, and Jamaica had a substantially higher risk of homicide victimization. Notably, few homicides involving foreign-born victims were gang- or drug-trade-related. With the growing number of immigrants in the United States, policy and prevention efforts should be guided by research.
Currently, 11 western states and 2 Canadian provinces use sport hunting as the primary mechanism for managing cougar (Puma concolor) populations. Yet the impacts of sustained harvest on cougar ...population dynamics and demographic structure are not well understood. We evaluated the effects of hunting on cougar populations by comparing the dynamics and demographic composition of 2 populations exposed to different levels of harvest. We monitored the cougar populations on Monroe Mountain in south-central Utah, USA, and in the Oquirrh Mountains of north-central Utah from 1996 to 2004. Over this interval the Monroe population was subjected to annual removals ranging from 17.6–51.5% (mean ± SE = 35.4 ± 4.3%) of the population, resulting in a >60% decline in cougar population density. Concurrently, the Oquirrh study area was closed to hunting and the population remained stationary. Mean age in the hunted population was lower than in the protected population (F = 9.0; df = 1, 60.3; P = 0.004), and in a pooled sample of all study animals, females were older than males (F = 13.8; df = 1, 60.3; P < 0.001). Females from the hunted population were significantly younger than those from the protected population (3.7 vs. 5.9 yr), whereas male ages did not differ between sites (3.1 vs. 3.4 yr), suggesting that male spatial requirements may put a lower limit on the area necessary to protect a subpopulation. Survival tracked trends in density on both sites. Levels of human-caused mortality were significantly different between sites (χ2 = 7.5; P = 0.006). Fecundity rates were highly variable in the protected population but appeared to track density trends with a 1-year lag on the hunted site. Results indicate that harvest exceeding 40% of the population, sustained for ≥4 years, can have significant impacts on cougar population dynamics and demographic composition. Patterns of recruitment resembled a source–sink population structure due in part to spatially variable management strategies. Based on these observations, the temporal scale of population recovery will most likely be a function of local harvest levels, the productivity of potential source populations, and the degree of landscape connectivity among demes. Under these conditions the metapopulation perspective holds promise for broad-scale management of this species.
The source-sink model of population dynamics predicts that density drives emigration of subordinate animals to habitats offering lower competition for resources. Several authors have suggested use of ...this model as a potential framework for conservation of exploited carnivores when precise enumeration is unfeasible. Dispersal is a critical behavioural mechanism for management based on this model, yet there is a lack of knowledge on the habitat and social conditions that motivate carnivore emigration and settlement. The cougar Puma concolor is a widely distributed and heavily exploited carnivore, indigenous to the western hemisphere. We evaluated patterns in cougar dispersal behaviour from two sites in Utah, differing in terms of management and the level of natural and anthropogenic habitat fragmentation. We used our results to evaluate three predictions with respect to cougar dispersal behaviour: 1) natal population density and maternal reproductive status prompt emigration, 2) movement of dispersing cougars is shaped by habitat configuration and permeability, and 3) dispersers preferentially settle in areas of high habitat quality and low conspecific density. We documented the emigration of 62 individuals and measured movement variables, including sex and site-specific frequency, distance, seasonality, direction and the habitat quality and harvest rates characterizing areas where immigrants settled. Although males and females exhibited pronounced differences in dispersal frequency, we found few differences in distance traveled, season of departure and direction moved. Dispersal occurred most frequently during spring, coinciding with the estrus pulse. Natural and anthropogenic obstacles modified landscape permeability, and therefore dispersal distances were shorter in fragmented habitats than in contiguous ones. Relative to males, females dispersed into habitats of lower productivity with higher mean annual harvest rates. Patterns in male settlement suggested habitat selection based on mating opportunities, whereas female settlement was predicated on avoiding conspecifics. Cougars in this Great Basin ecosystem largely conformed to source-sink predictions. Results can be used to parameterize source-sink models based on animal behaviour and landscape permeability to conserve exploited carnivores, under conditions of population expansion or recolonization of habitats where Allee effects are a limiting factor.
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