Bald eagle search algorithm for solving a three-dimensional path planning problem.

Three-dimensional path planning refers to determining an optimal path in a three-dimensional space with obstacles, so that the path is as close to the target location as possible, while meeting some other constraints, including distance, altitude, threat area, flight time, energy consumption, and so on. Although the bald eagle search algorithm has the characteristics of simplicity, few control parameters, and strong global search capabilities, it has not yet been applied to complex three-dimensional path planning problems. In order to broaden the application scenarios and scope of the algorithm and solve the path planning problem in three-dimensional space, we present a study where five three-dimensional geographical environments are simulated to represent real-life unmanned aerial vehicles flying scenarios. These maps effectively test the algorithm's ability to handle various terrains, including extreme environments. The experimental results have verified the excellent performance of the BES algorithm, which can quickly, stably, and effectively solve complex three-dimensional path planning problems, making it highly competitive in this field.

The comparison of gut microbiota between wild and captive Asian badgers (Meles leucurus) under different seasons.

The gut microbiota plays an important role in the immunology, physiology and growth and development of animals. However, currently, there is a lack of available sequencing data on the gut microbiota of Asian badgers. Studying the gut microbiota of Asian badgers could provide fundamental data for enhancing productivity and immunity of badgers' breeding, as well as for the protection of wild animals. In this study, we first characterized the composition and structure of the gut microbiota in the large intestines of wild and captive Asian badgers during summer and winter by sequencing the V3-V4 region of the 16S ribosomal RNA gene. A total of 9 dominant phyla and 12 genera among the bacterial communities of the large intestines exhibited significant differences. Our results showed that Firmicutes and Proteobacteria were the most predominant in both wild and captive badgers, regardless of the season. Romboutsia, Streptococcus and Enterococcus may represent potential sources of zoonoses, warranting further attention and study. Our findings indicated that the diversity and availability of food resources were the most important influencing factors on the gut microbiota of Asian badgers, providing fundamental data for the protection and conservation of wild animals. Variation in the gut microbiota due to season, age and sex in both wild and captive Asian badgers should be considered in future research directions. Furthermore, combined multi-omics studies could provide more information for wild animal conservation, and enhancing our understanding of the molecular mechanism between the microbiota and host.

Fine-Scale Interactions between Leopard Cats and Their Potential Prey with Contrasting Diel Activities in a Livestock-Dominated Nature Reserve.

Habitat use and the temporal activities of wildlife can be largely modified by livestock encroachment. Therefore, identifying the potential impacts of livestock on the predator-prey interactions could provide essential information for wildlife conservation and management. From May to October 2017, we used camera trapping technology to investigate fine-scale spatiotemporal interactions in a predator-prey system with the leopard cat (Prionailurus bengalensis) as a common mesopredator, and its prey with contrasting activity patterns (i.e., nocturnal rats and diurnal squirrels) in a livestock-dominated nature reserve in Northern China. We found that the prey species showed different habitat preferences with the leopard cats. The nocturnal rats had strong positive effects on the site-use of the leopard cats, while the influence of livestock on the diurnal squirrels' site-use changed from strong positive effects to weak effects as the livestock disturbance increased. The temporal overlap between the leopard cats and the nocturnal rats was almost four times that of the leopard cats and the diurnal squirrels, regardless of the livestock disturbance. Our study demonstrated that the fine-scale spatiotemporal use patterns of the leopard cats were consistent and highly correlated with the nocturnal rats under livestock disturbance. We suggest that appropriate restrictions on livestock disturbance should be implemented by reserve managers to reduce the threat to wildlife and achieve multi-species coexistence.

Relationships between humans and ungulate prey shape Amur tiger occurrence in a core protected area along the Sino-Russian border.

Large carnivore populations are globally threatened by human impacts. Better protection could benefit carnivores, co-occurring species, and the ecosystems they inhabit. The relationship between carnivores and humans, however, is not always consistent in areas of high human activities and is often mediated through the effects of humans on their ungulate prey. To test assumptions regarding how prey abundance and humans affect carnivore occurrence, density, and daily activity patterns, we assessed tiger-prey-human spatiotemporal patterns based on camera-trapping data in Hunchun Nature Reserve, a promising core area for tiger restoration in China. Our study area contained seasonally varying levels of human disturbance in summer and winter. We used N-mixture models to predict the relative abundance of ungulate prey considering human and environmental covariates. We estimated tiger spatial distribution using occupancy models and models of prey relative abundance from N-mixture models. Finally, we estimated temporal activity patterns of tigers and prey using kernel density estimates to test for temporal avoidance between tigers, prey, and humans. Our results show that human-related activities depressed the relative abundance of prey at different scales and in different ways, but across species, the relative abundance of prey directly increased tiger occupancy. Tiger occupancy was strongly positively associated with the relative abundance of sika deer in summer and winter. The crepuscular and nocturnal tigers also apparently synchronized their activity with that of wild boar and roe deer. However, tigers temporally avoided human activity without direct spatial avoidance. Our study supports the effects of humans on tigers through human impacts on prey populations. Conservation efforts may not only target human disturbance on predators, but also on prey to alleviate human-carnivore conflict.

The complete mitochondrial genome of the North Chinese Leopard (Panthera pardus japonensis).

The North Chinese Leopard (Panthera pardus japonensis) is an endemic subspecies of Panthera pardus to China, living in small and isolated populations with a severely fragmented distribution. Here we first sequenced and annotated its complete mitochondrial genome. The total length of the North Chinese Leopard is of 16,966 base pairs that consist of 2 rRNA gene, 22 tRNA genes, 13 protein-coding genes, 1 OLR and 1 control region (CR). The structures of the genomes were highly similar to other Felidae.

Estimating abundance and density of Amur tigers along the Sino-Russian border.

As an apex predator the Amur tiger (Panthera tigris altaica) could play a pivotal role in maintaining the integrity of forest ecosystems in Northeast Asia. Due to habitat loss and harvest over the past century, tigers rapidly declined in China and are now restricted to the Russian Far East and bordering habitat in nearby China. To facilitate restoration of the tiger in its historical range, reliable estimates of population size are essential to assess effectiveness of conservation interventions. Here we used camera trap data collected in Hunchun National Nature Reserve from April to June 2013 and 2014 to estimate tiger density and abundance using both maximum likelihood and Bayesian spatially explicit capture-recapture (SECR) methods. A minimum of 8 individuals were detected in both sample periods and the documentation of marking behavior and reproduction suggests the presence of a resident population. Using Bayesian SECR modeling within the 11 400 km(2) state space, density estimates were 0.33 and 0.40 individuals/100 km(2) in 2013 and 2014, respectively, corresponding to an estimated abundance of 38 and 45 animals for this transboundary Sino-Russian population. In a maximum likelihood framework, we estimated densities of 0.30 and 0.24 individuals/100 km(2) corresponding to abundances of 34 and 27, in 2013 and 2014, respectively. These density estimates are comparable to other published estimates for resident Amur tiger populations in the Russian Far East. This study reveals promising signs of tiger recovery in Northeast China, and demonstrates the importance of connectivity between the Russian and Chinese populations for recovering tigers in Northeast China.