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There are several mechanisms that allow plants to temporarily escape from top-down control. One of them is trophic cascades triggered by top predators or pathogens. Another is satiation of consumers by mast seeding. These two mechanisms have traditionally been studied in separation. However, their combined action may have a greater effect on plant release than either process alone. In 2015, an outbreak of a disease (African swine fever, ASF) caused a crash in wild boar (Sus scrofa) abundance in Białowieża Primeval Forest. Wild boar are important consumers of acorns and are difficult to satiate relative to less mobile granivores. We hypothesized that the joint action of the ASF outbreak and masting would enhance regeneration of oaks (Quercus robur). Data from ungulate exclosures demonstrated that ASF led to reduction in acorn predation. Tree seedling data indicated that oak recruitment increased twofold relative to pre-epidemic period. Our results showed that perturbations caused by wildlife disease travel through food webs and influence forest dynamics. The outbreak of ASF acted synergistically with masting and removed herbivore top-down control of oaks by mobile consumers. This illustrates that the ASF epidemic that currently occurs across Europe can have broad effects on forest dynamics. [ABSTRACT FROM AUTHOR]

The wild boar Sus scrofa is one of the widely spread ungulate species in Europe, yet the origin and genetic structure of the population inhabiting Central and Eastern Europe are not well recognized. We analysed 101 newly obtained sequences of complete mtDNA genomes and 548 D-loop sequences of the species and combined them with previously published data. We identified five phylogenetic clades in Europe with clear phylogeographic pattern. Two of them occurred mainly in western and central part of the continent, while the range of the third clade covered North-Eastern, Central and South-Eastern Europe. The two other clades had rather restricted distribution. In Central Europe, we identified a contact zone of three mtDNA clades. Population genetic structure reflected clear phylogeographic pattern of wild boar in this part of Europe. The contribution of lineages originating from the southern (Dinaric-Balkan) and eastern (northern cost of the Black Sea) areas to the observed phylogeographic pattern of the species in Central and Eastern Europe was larger than those from the regions located in southern France, Iberian, and Italian Peninsulas. The present work was the first mitogenomic analysis conducted in Central and Eastern Europe to study genetic diversity and structure of wild boar population. [ABSTRACT FROM AUTHOR]

There is a growing evidence that members of animal groups synchronize their vigilance behavior to minimize predation risk. Because synchronized vigilance deviates from the classical vigilance models, which assume independent scanning, it is important to understand when and why it occurs. We explored vigilance behavior of wild boar (Sus scrofa) in a population subject to spatial variation in human hunting risk and seasonal variation in food availability. Group members synchronized their vigilance behavior. We hypothesized that vigilance synchronization would be context dependent and the trade-off between energy gain and safety would shape the relationship between the degree of vigilance synchronization and group size. We predicted weaker synchronization in large groups under heavy predation risk, due to benefits of numerical dilution, and stronger synchronization in large groups when food is limiting, due to intense food competition. The degree of synchronization decreased with increasing group size in the area where human hunting added another risk factor to the natural predation, pointing at the safety benefits of vigilance synchrony for members of small groups and the role of human-induced risk in shaping vigilance synchrony. We found no relation between vigilance synchrony and group size in a food scarce, winter season. However, low levels of vigilance and its synchronization observed in winter indicated that energy gain was prioritized over safety. Thus, members of wild boar groups can adjust levels of vigilance and its synchronization depending on the forage-risk trade-off set by the ecological context. [ABSTRACT FROM AUTHOR]