In recent decades, grazing by wild and domestic ungulates has become a strategy for conservation management to restore or maintain open landscapes. One of the species playing an increasing role in ecological restoration is the European bison – the largest terrestrial mammal in Europe. We studied the impact of this large herbivore and other ungulates (moose, red deer, and roe deer) on tree encroachment in open habitats in the Białowieża Primeval Forest (Poland). On 30 study plots located in meadows, we measured crown volume and the density of woody vegetation and monitored visitation and behavior of ungulates with the use of camera traps. The mean visitation rate to meadows by European bison was 0.11 ind./day/plot, and 0.22 ind./day/plot by other ungulates. The duration of foraging was significantly higher in European bison (55.8 s) than in other ungulates (16.3 s). The density of woody vegetation on meadows varied from 13 to 6213 ind./ha and the crown volume from 0.6 to 1145 m³/ha. We found that increased visitation by European bison resulted in a significant reduction in the density and volume of woody vegetation in meadows. The reducing effect on woody vegetation was over eight times higher in frequently visited plots when compared to unvisited plots – the density of woody vegetation decreased from 879 to 101 saplings/ha, while the crown volume declined from 295 to 35 m³/ha. In addition, the density of woody vegetation was related to the level of meadow openness. Less open (smaller) meadows had a significantly higher density of woody vegetation than meadows characterized by high openness. Combined visitation by other ungulates did not affect either the volume or density of woody vegetation. The most plausible mechanism of observed patterns can be a remarkably higher foraging activity in meadows by bison in comparison to other ungulates. As a consequence, European bison, being adapted to open habitats, can effectively reduce the growth of tree seedlings and limit tree encroachment at the initial stages of forest succession. Thus, populations of this wild herbivore can play a role in the restoration or maintenance of open habitats and woody pastures that serve as an important foraging ground for bison in suboptimal forests, where populations of these herbivores were restored.

近几十年来，野生和有蹄类动物的放牧已成为养护管理恢复或维护开放景观的一种策略。在生态恢复中起越来越重要作用的物种之一是欧洲野牛-欧洲最大的陆生哺乳动物。我们研究了这种大型食草动物和其他有蹄类动物（驼鹿，马鹿和ro鹿）对Białowieża原始森林（波兰）中开放栖息地树木侵占的影响。在草地上的30个研究地块上，我们测量了树冠的体积和木本植物的密度，并使用相机陷阱监控了有蹄类动物的探视和行为。欧洲野牛对草地的平均探望率为0.11 ind./day/plot，其他有蹄类动物为0.22 ind./day/plot。欧洲野牛的觅食时间长得多（55。8 s）比其他有蹄类动物（16.3 s）高。草甸木本植物的密度从13到6213不等 ind./ha，树冠体积从0.6到1145 m ³ / ha。我们发现欧洲野牛的拜访增加导致草甸木质植被的密度和体积显着降低。与未参观的地块相比，经常参观的地块对木本植物的减少作用要高出八倍以上–木本植物的密度从879棵树苗/公顷减少到101棵树苗/公顷，树冠体积从295棵减少到35 m ³/哈。此外，木本植被的密度与草甸的开放程度有关。与以开放度高为特征的草地相比，开放度较小（较小）的草地具有较高的木本植被密度。其他有蹄类动物的联合造访既不影响木质植被的数量，也不影响其密度。与其他有蹄类动物相比，观察到的模式最合理的机制可能是野牛在草地上的觅食活动明显增加。结果，适应野外栖息地的欧洲野牛可以有效地减少树木幼苗的生长，并在森林演替初期限制树木的入侵。因此，