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Rapid environmental changes challenge the resilience of wildlands. The western portion of the Lake Tahoe Basin in California is an important ecological and cultural hotspot that is at risk of degradation from current and future environmental pressures. Historical uses, fire suppression, and a changing climate have created forest landscape conditions at risk of drought stress, destructive fire, and loss of habitat diversity. We prospectively modeled forest landscape conditions for a period of 100 years to evaluate the efficacy of 5 unique management scenarios in achieving desired landscape conditions. Management scenarios ranged from no management other than fire suppression to applying treatments consistent with historical fire frequencies and extent (i.e., regular and broadscale biomass reduction). We developed a decision support tool to evaluate environmental and social outcomes within a single framework to provide a transparent set of costs and benefits. Results illuminated underlying mechanisms of forest resilience and provided actionable guidance to decision makers. Sixteen attributes were assessed in the model after assigning weights to each. We found that removing forest biomass across the landscape, particularly when accomplished using extensive fire-based removal techniques, led to highly favorable conditions for environmental quality and promoted overall landscape resilience. Environmental conditions resulting from extensive fire-based biomass removal also had nominal variation over time, in contrast with strategies that had less extensive and/or used physical removal techniques (e.g., mechanical thinning). Our analysis provides a transparent approach to assess large datasets with complex and interacting variables. Ultimately, we aim to provide insights into the complexities of maintaining optimal conditions and managing landscapes to promote ecosystem resilience in a changing world. [ABSTRACT FROM AUTHOR]

Why are some mammals more vulnerable to extinction than others? Past studies have explored many life history traits as correlates of extinction, but have not been successful at developing a unified understanding of why some species become extinct while other species persist despite living at the same time, under similar conditions, and facing equivalent challenges. I propose that the lens of wildlife behavior may bring into focus a more comprehensive view of why some species have gone extinct while others persist. The fossil record has recorded extinction events over carnivoran history; unfortunately, behavior is not well recorded in the fossil record. As a proxy for behavior, I examine relative encephalization (RE), brain size after controlling for body mass and phylogeny, as it has been found to be biologically relevant in understanding a wide variety of animal behavioral traits. I focus on the data-rich order Carnivora for which there are comprehensive data on brain size and extinction between 40 and 0.012 million years ago. I use Cox proportional-hazards models to assess the role that RE and body size have played on extinction risk for 224 species in the order Carnivora that existed between 40 and 0.012 million years ago. I show generally that carnivoran species with reduced RE had higher relative risks of extinction. Additionally, I find an interaction between RE and body size such that RE had the largest effects on relative extinction risk in the smallest-bodied species. These results suggest that RE is important for understanding extinction risk in Carnivora over geologic time frames. [ABSTRACT FROM AUTHOR]

Self-medication behaviour is the use of natural materials or chemical substances to manipulate behaviour or alter the body's response to parasites or pathogens. Self-medication can be preventive, performed before an individual becomes infected or diseased, and/or therapeutic, performed after an individual becomes infected or diseased. We summarized all available reports of self-medication in mammals and reconstructed its evolution. We found that reports of self-medication were restricted to eutherian mammals and evolved at least four times independently. Self-medication was most commonly reported in primates. Detailed analyses of primates suggest that self-medication is a life-history trait associated with body size, absolute brain size and longevity, but we found no support for the hypothesis that self-medication evolved to reduce the costs of social living. Large, longer-lived species might thus benefit uniquely from self-medication. [ABSTRACT FROM AUTHOR]

Increases in relative encephalization (RE), brain size after controlling for body size, comes at a great metabolic cost and is correlated with a host of cognitive traits, from the ability to count objects to higher rates of innovation. Despite many studies examining the implications and trade-offs accompanying increased RE, the relationship between mammalian extinction risk and RE is unknown. I examine whether mammals with larger levels of RE are more or less likely to be at risk of endangerment than less-encephalized species. I find that extant species with large levels of encephalization are at greater risk of endangerment, with this effect being strongest in species with small body sizes. These results suggest that RE could be a valuable asset in estimating extinction vulnerability. Additionally, these findings suggest that the cost benefit trade-off of RE is different in large-bodied species when compared with small-bodied species. [ABSTRACT FROM AUTHOR]

The article presents the discussion on technology revolutionizing the study of organisms in the natural environment monitoring the distribution and abundance of species along with climate and other variables.

Many forests of the western United States have undergone over one hundred years of anthropogenic impacts that have led to increased tree density, homogenization in forest structure, and accumulation of woody material, which combined with a changing climate pose threats to valued social and ecological features. In California, recent waves of tree mortality and unprecedented large and destructive fires have led to rising concerns about the impact of these disturbances on biodiversity and how forest management actions can mitigate negative impacts. To better understand the degree to which different management scenarios could mitigate the negative impacts of these disturbances on biodiversity, we used a spatially explicit modeling platform to model forest management impacts on habitat for terrestrial vertebrate species in the Lake Tahoe Basin of California and Nevada. Specifically, we modeled how 5 different management scenarios that differed in the type of fuel reduction treatment (e.g., fire and mechanical removal of vegetation) and extent of area treated influenced the amount, value, and distribution of reproductive habitat for the 159 species present in the study area. Our model results suggested that within the study area forest growth was predicted to out-pace disturbance leading to a higher percentage of late seral conditions; however, choice of management strategy impacted the composition and structure of the forested landscape leading to different trajectories for wildlife. In general, scenarios that allowed for more extensive use of fire led to a more equitable distribution of habitat types, whereas extensive thinning by hand and mechanical methods resulted in future forest structure that provided better outcomes in terms of reproductive habitat for wildlife. Our modeling results also suggested that low to moderate management strategies were not likely to change the current trajectory to more dense forests dominated by fewer species. [ABSTRACT FROM AUTHOR]

Artificial light at night (ALAN) is increasing in extent and intensity across the globe. It has been shown to interfere with animal sensory systems, orientation and distribution, with the potential to cause significant ecological impacts. We analysed the locations of 102 mountain lions (Puma concolor) in a light-polluted region in California. We modelled their distribution relative to environmental and human-disturbance variables, including upward radiance (nearby lights), zenith brightness (sky glow) and natural illumination from moonlight. We found that mountain lion probability of presence was highly related to upward radiance, that is, related to lights within approximately 500 m. Despite a general pattern of avoidance of locations with high upward radiance, there were large differences in degree of avoidance among individuals. The amount of light from artificial sky glow was not influential when included together with upward radiance in the models, and illumination from moonlight was not influential at all. Our results suggest that changes in visibility associated with lunar cycles and sky glow are less important for mountain lions in their selection of light landscapes than avoiding potential interactions with humans represented by the presence of nearby lights on the ground. This article is part of the theme issue 'Light pollution in complex ecological systems'. [ABSTRACT FROM AUTHOR]

Roads fragment animal populations, vehicles kill and injure animals, and traffic may affect animal behavior. Mitigation efforts (e.g., wildlife underpasses) are constructed to prevent fragmentation and reduce wildlife-vehicle collisions. However, little is known about traffic's proximal effects on wildlife behavior and use of mitigation measures. We quantified the time that elk (Cervus elaphus) and white-tailed deer (Odocoileus virginianus) allocated to foraging, vigilance, and flight behavior before and after vehicle passage. Both species increased vigilance and flight behaviors and reduced time spent foraging in response to vehicles. Both species were more likely to move through the underpass if they exhibited foraging behavior; we also found a marginally significant trend that animals were less likely to use the underpass after vigilance behavior. Knowledge that vehicle movement influences wildlife behavior underscores the importance of consideration given to road and crossing structure design. Additionally, findings of species-specific response to vehicle passage are important in understanding potential fitness consequences of anthropogenic disturbance. [ABSTRACT FROM AUTHOR]