Vultures provide an essential ecosystem service through removal of carrion, but globally, many populations are collapsing and several species are threatened with extinction. Widespread declines in vulture populations could increase the availability of carrion to other organisms, but the ways facultative scavengers might respond to this increase have not been thoroughly explored. We aimed to determine whether facultative scavengers increase carrion consumption in the absence of vulture competition and whether they are capable of functionally replacing vultures in the removal of carrion biomass from the landscape. We experimentally excluded 65 rabbit carcasses from vultures during daylight hours and placed an additional 65 carcasses that were accessible to vultures in forested habitat in South Carolina, USA during summer (June–August). We used motion‐activated cameras to compare carrion use by facultative scavenging species between the experimental and control carcasses. Scavenging by facultative scavengers did not increase in the absence of competition with vultures. We found no difference in scavenger presence between control carcasses and those from which vultures were excluded. Eighty percent of carcasses from which vultures were excluded were not scavenged by vertebrates, compared to 5% of carcasses that were accessible to vultures. At the end of the 7‐day trials, there was a 10.1‐fold increase in the number of experimental carcasses that were not fully scavenged compared to controls. Facultative scavengers did not functionally replace vultures during summer in our study. This finding may have been influenced by the time of the year in which the study took place, the duration of the trials, and the spacing of carcass sites. Our results suggest that under the warm and humid conditions of our study, facultative scavengers would not compensate for loss of vultures. Carcasses would persist longer in the environment and consumption of carrion would likely shift from vertebrates to decomposers. Such changes could have substantial implications for disease transmission, nutrient cycling, and ecosystem functioning.

Aim Vertebrates are declining worldwide, yet a comprehensive examination of the sources of mortality is lacking. We conducted a global synthesis of terrestrial vertebrate cause‐specific mortality to compare the sources of mortality across taxa and determine predictors of susceptibility to these sources of mortality. Location Worldwide. Time period 1970–2018. Major taxa studied Mammals, birds, reptiles and amphibians. Methods We searched for studies that used telemetry to determine the cause of death of terrestrial vertebrates. We determined whether each mortality was caused by anthropogenic or natural sources and further classified mortalities within these two categories (e.g. harvest, vehicle collision and predation). For each study, we determined the diet and average adult body mass of the species and whether the study site permitted hunting. Mortalities were separated into juvenile or adult age classes. We used linear mixed effects models to predict the percentage of mortality from each source and the overall magnitude of mortality based on these variables. Results We documented 42,755 mortalities of known cause from 120,657 individuals representing 305 vertebrate species in 1,114 studies. Overall, 28% of mortalities were directly caused by humans and 72% from natural sources. Predation (55%) and legal harvest (17%) were the leading sources of mortality. Main conclusions Humans were directly responsible for more than one‐quarter of global terrestrial vertebrate mortality. Larger birds and mammals were harvested more often and suffered increased anthropogenic mortality. Anthropogenic mortality of mammals and birds outside areas that prohibited hunting was higher than within areas where hunting was prohibited. Mammals experienced shifts from predominately natural to anthropogenic mortality as they matured. Humans are a major contributor to terrestrial vertebrate mortality, potentially impacting evolutionary processes and ecosystem functioning.

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Over the Earth's terrestrial surface, wildlife species are adversely affected by an increasing number of anthropogenic impacts to the landscape, collectively termed the "human footprint". However, there is limited understanding of how the human footprint influences cause-specific mortality in wildlife. We conducted a synthesis of cause-specific mortality of North American terrestrial mammals, compiling 247 studies that as a group determined the cause of death of 6607 adult mammals among 19,910 individuals monitored. Species lifespan as well as the interaction between lifespan and the human footprint were positively associated with the proportion of mortality attributed to anthropogenic sources. Our results indicate that anthropogenic mortality in mammals increases with increasing human-associated impacts on the landscape, and that longer-lived species are affected more than their shorter-lived counterparts. This pattern likely accounts for the extirpation of longer-lived, larger-bodied mammals from many human-dominated areas. We also found that as the human footprint increased in magnitude, harvest mortality declined while vehicle mortality increased. These shifts in mortality can have substantial implications for understanding wildlife population dynamics and managing wildlife populations across landscapes impacted by anthropogenic activities.

Increasing sand temperatures resulting from climate change may negatively impact sea turtle nests by altering sex ratios and decreasing reproductive output. We analyzed the effect of nest shading and watering on sand temperatures as climate mitigation strategies in a beach hatchery at Playa Grande, Costa Rica. We set up plots and placed thermocouples at depths of 45cm and 75cm. Half of the plots were shaded and half were exposed to the sun. Within these exposure treatments, we applied three watering treatments over one month, replicating local climatic conditions experienced in this area. We also examined gravimetric water content of sand by collecting sand samples the day before watering began, the day after watering was complete, and one month after completion. Shading had the largest impact on sand temperature, followed by watering and depth. All watering treatments lowered sand temperature, but the effect varied with depth. Temperatures in plots that received water returned to control levels within 10 days after watering stopped. Water content increased at both depths in the two highest water treatments, and 30 days after the end of water application remained higher than plots with low water. While the impacts of watering on sand temperature dissipate rapidly after the end of application, the impacts on water content are much more lasting. Although less effective at lowering sand temperatures than shading, watering may benefit sea turtle clutches by offsetting negative impacts of low levels of rain in particularly dry areas. Prior to implementing such strategies, the natural conditions at the location of interest (e.g. clutch depth, environmental conditions, and beach characteristics) and natural hatchling sex ratios should be taken into consideration. These results provide insight into the effectiveness of nest shading and watering as climate mitigation techniques and illustrate important points of consideration in the crafting of such strategies.

Roads have numerous negative impacts for mammals, but may also serve as attractants due to altered vegetation or provisioning of resources. We reviewed the use of roads and their associated features by mammals, in order to understand the ecological factors contributing to road use. We documented 129 studies that recorded road use by 116 mammalian species, spanning 15 orders and 35 families, in six continents. Carnivora was the most common order (40 species, 34% of all 116 species), followed by Artiodactyla (24 species, 20%) and Rodentia (21 species, 18%). The species were placed in the IUCN categories Least Concern (88 species, 76% of all 116 species), Vulnerable (11 species, 9%), Near Threatened (9 species, 8%), Endangered (6 species, 5%), and Critically Endangered (2 species, 2%). We assigned road use to five ecological categories, reflecting the reason for it, with subcategories where appropriate: (1) communication; (2) foraging (subcategories: anthropogenic food, herbivory, predation, salt, scavenging, water); (3) movement (subcategories: bridges, environmental alterations, habitat connectivity); (4) refuge (subcategories: avoidance, burrowing and denning, cover, roosting); and (5) thermoregulation. Foraging, movement, and refuge were the most common uses. Roads provide a variety of resources to mammals, but road use is highly dynamic in time and space. We suggest that the use of roads by mammals is extensive, both geographically and taxonomically. Road use is likely to influence mammalian ecology while contributing to the risk of collisions with vehicles.

Abstract. Spontaneous equine pulmonary granular cell tumors were diagnosed in six mature horses at slaughter. These tumors were grossly recognized as multiple (5/6) or single (1/6) creamy white, firm nodules. The tumors, located adjacent to bronchi and bronchioles, often invaded airways, resulting in partial to complete occlusion of the lumina. Neoplastic cells were rounded to polyhedral with numerous eosinophilic cytoplasmic granules that reacted uniformly positive with S-100 and neuron-specific enolase antibodies and multifocally with glial fibrillary acidic protein antibodies. These cells were negative for muscle-specific actin, lysozyme, cytokeratin, chromogranin A, and myelin basic protein antigens and did not stain with silver by the Grimelius technique. Uniformly blue-green and scattered pink intracytoplasmic granules were evident with luxol fast blue and periodic acid-Schiff counterstain for myelin and myelin breakdown products. Histochemical and immunohistochemical staining results of these tumors suggest that they are composed primarily of myelinating Schwann cells with lesser numbers of scattered nonmyelinating Schwann cells. The morphologic features of the equine pulmonary granular cell tumors are strikingly similar to those of endobronchial granular cell tumors of human beings.