Knowledge about breeding biology is often incomplete in species with complex reproductive strategies. The brown bear Ursus arctos is a polygamous seasonal breeder inhabiting a wide variety of habitats and environmental conditions. We compiled information about brown bear breeding season dates from 36 study areas across their distribution range in the Palearctic and Nearctic regions and investigated how their breeding phenology relates to geographical factors (latitude, photoperiod, altitude and region). Brown bear matings were observed for 8 months, from April to November, with a peak in May-July. We found a 59-day difference in the onset of bear breeding season among study areas, with an average 2.3 days delay for each degree of latitude northwards. The onset of the breeding season showed a strong relationship with photoperiod and latitude, but not with region (i.e. Palearctic vs Nearctic) and altitude. First observations of bear mating occurred earlier in areas at lower latitudes. Photoperiod ranged between 14 and 18 hours at the beginning of the season for most of the study areas. The duration of the breeding season ranged from 25 to 138 days among study areas. None of the investigated factors was related to the length of the breeding season. Our results support the relevance of photoperiod to the onset of breeding, as found in other ursids, but not a shorter breeding season at higher latitudes, a pattern reported in other mammals. Our findings suggest a marked seasonality of bear reproductive behaviour, but also certain level of plasticity. Systematic field observations of breeding behaviour are needed to increase our knowledge on the factors determining mating behaviour in species with complex systems and how these species may adapt to climate change.
The wolf is a generalist-opportunistic predator that displays diverse and remarkably adaptable feeding strategies across its range with local adaptations to certain prey species depending on their availability and vulnerability. The multi-prey system of the Slovak Carpathians supports important portion of the European wolf population; however, it has been markedly understudied. We evaluated winter diet composition and prey selection of Slovak wolves based on 321 scat samples collected between September–April within four different study areas during 2015–2017. The winter diet of wolves in the Slovak Carpathians was characterized by a 98% occurrence of wild large-sized and medium-sized ungulates with red deer occurring in wolf scats most often, consistent with their highest density among other wild ungulates. However, by comparing the consumption with availability of wild prey, we found that wolves in fact selected for wild boar especially in areas with higher altitudinal range, while selected for red deer in areas with low altitudinal range where this prey species was more spatially predictable. Although wolves showed the potential to switch between red deer and wild boar when their density increases, we found that this variation can be rather linked to changing prey vulnerability, which is dependent on particular environmental conditions at local scale such as topography and snow accumulation. The present study provides valuable insights into the winter foraging ecology of Slovak wolves in a multi-prey system of the Carpathians and allows for practical implications in the management of the rapidly increasing populations of wild ungulates across Europe.
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