The increasing trend of large carnivore attacks on humans not only raises human safety concerns but may also undermine large carnivore conservation efforts. Although rare, attacks by brown bears Ursus arctos are also on the rise and, although several studies have addressed this issue at local scales, information is lacking on a worldwide scale. Here, we investigated brown bear attacks (n = 664) on humans between 2000 and 2015 across most of the range inhabited by the species: North America (n = 183), Europe (n = 291), and East (n = 190). When the attacks occurred, half of the people were engaged in leisure activities and the main scenario was an encounter with a female with cubs. Attacks have increased significantly over time and were more frequent at high bear and low human population densities. There was no significant difference in the number of attacks between continents or between countries with different hunting practices. Understanding global patterns of bear attacks can help reduce dangerous encounters and, consequently, is crucial for informing wildlife managers and the public about appropriate measures to reduce this kind of conflicts in bear country.
Attacks by wild carnivores on humans represent an increasing problem in urban areas across North America and their frequency is expected to rise following urban expansion towards carnivore habitats. Here, we analyzed records of carnivore attacks on humans in urban areas of the U.S. and Canada between 1980 and 2016 to analyze the general patterns of the attacks, as well as describe the landscape structure and, for those attacks occurring at night, the light conditions at the site of the attacks. We found that several behavioral and landscape-related factors were recurrent elements in the attacks recorded. The species for which the attack locations were available (coyote and black bear) attacked in areas with different conditions of landscape structure and artificial light. Specifically, black bears attacked more frequently in areas with abundant and aggregated vegetation cover and scarce buildings and roads, while coyotes attacked in a broader range of landscape conditions. At night, black bears attacked in generally darker areas than coyotes. By providing a comprehensive perspective of the phenomenon, this study will improve our understanding of how effective strategies aimed at reducing the frequency of risky encounters in urban areas should be developed.
Plant provenance, plant facilitation and the characteristics of restoration sites are critical determinants of revegetation success. Surprisingly, however, very little is known about how these key factors interact, both with each other and to complex patterns of recruitment in target plant species. We investigated, for the first time, the potential of combining seed provenance, plant facilitation and restoration site characteristics to guide revegetation efforts. As a model system, we used the Iberian pear (Pyrus bourgaeana) and three potential nurse shrub species. To this end, we completed a comprehensive reciprocal transplant experiment in five P. bourgaeana populations within a fragmented landscape at the Doñana Biosphere Reserve (SW Spain). There were marked differences among provenances for seedling emergence and growth, as well as for recruitment, but no evidence of local adaptation was found. Shrubs generally had a positive or neutral effect on P. bourgaeana seedling performance with, for example survival underneath shrubs being, on average, twice as high as in open microhabitats. Interestingly, however, the magnitude and even the sign of such plant–plant interactions changed with both sowing locality and seed provenance. For instance, shrubs enhanced seedling survival and recruitment at the end of the study in four of the five sowing localities, whereas it decreased it in the remaining locality. Also, although nurse shrubs lessened seedling size of two provenances, it did not have a significant effect on the other three. Synthesis and applications. We show how revegetation success can be maximized, not only by selecting the most appropriate plant material, taking advantage of plant facilitative interactions and selecting the right restoration site, but also by using these factors in an integrated fashion. We propose local managers efficiently undertake future revegetation campaigns by mixing seeds from several genetically adequate source populations in numbers weighted according to previously estimated provenance‐specific recruitment successes. Our novel approach can help to guide revegetation of many tree and plant species living in stressful conditions, such as arid, semi‐arid and high mountain habitats.
The study of plant-frugivore interactions is essential to understand the ecology and evolution of many plant communities. However, very little is known about how interactions among frugivores indirectly affect plant reproductive success. In this study, we examined direct interactions among vertebrate frugivores sharing the same fruit resources. Then, we inferred how the revealed direct interspecific interactions could lead to indirect (positive or negative) effects on reproductive success of fleshy fruited plants. To do so, we developed a new analytical approach that combines camera trap data (spatial location, visitor species, date and time, activity) and tailored null models that allowed us to infer spatial-temporal interactions (attraction, avoidance or indifference) between pairs of frugivore species. To illustrate our approach, we chose to study the system composed by the Mediterranean dwarf palm, Chamaerops humilis, the Iberian pear tree, Pyrus bourgaeana, and their shared functionally diverse assemblages of vertebrate frugivores in a Mediterranean area of SW Spain. We first assessed the extent to which different pairs of frugivore species tend to visit the same or different fruiting individual plants. Then, for pairs of species that used the same individual plants, we evaluated their spatial-temporal relationship. Our first step showed, for instance, that some prey frugivore species (e.g. lagomorphs) tend to avoid those C. humilis individuals that were most visited by their predators (e.g. red foxes). Also, the second step revealed temporal attraction between large wild and domestic frugivore ungulates (e.g. red deer, cows) and medium-sized frugivores (e.g. red foxes) suggesting that large mammals could facilitate the C. humilis and P. bourgaeana exploitation to other smaller frugivores by making fruits more easily accessible. Finally, our results allowed us to identify direct interaction pathways, that revealed how the mutualistic and antagonistic relations between animal associates derived into indirect effects on both plants seed dispersal success. For instance, we found that large-sized seed predators (e.g. ungulates) had a direct positive effect on the likelihood of visits by legitimate seed dispersers (e.g. red foxes) to both fleshy fruited plants. Then, seed predators showed an indirect positive effect on the plants' reproductive success.
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