The majority of European Bison subpopulations were (re)introduced to forest habitats (Kerley et al. 2012). However, patterns of habitat use strongly vary between different populations and are strongly shaped by habitat structure (forest cover) and management actions (Hofman-Kamińska et al. 2018). Preference towards open habitats such as meadows, river valleys, abandoned farmland, forest gaps and clearing is observed (Kuemmerle et al. 2011, Kowalczyk et al. 2019, Zielke et al. 2019). European Bison are mixed feeders or browsers (Gębczyńska et al. 1991, Kowalczyk et al. 2011, 2019; Bocherens et al. 2015, Merceron et al. 2015), which continuously adjust their diet with seasonal availability of easily digestible non-grass vegetation (Kowalczyk et al. 2019). In winter, bison foraging ecology can be strongly influenced by supplementary feeding (Kowalczyk et al. 2011). Non-fed populations usually utilise open habitats and agriculture areas. Farm crops depredation is compensated in some countries.

European Bison are not territorial, and their spatial organisation and population density are influenced by habitat quality and food abundance (Kerley et al. 2020). Home ranges of European Bison cover from several dozen to two hundred km², in relation to habitat structure and seasonal migrations (Kowalczyk and Plumb 2020). Home range sizes of mixed groups are influenced by the distribution and availability of forage resources, while home range of mature males is more related to reproductive behaviour and activity than food-related factors. In many populations seasonal migrations are observed, driven by supplementary feeding or access to food resources out of forest habitats, or having altitudinal character to avoid harsh winter conditions (Kowalczyk et al. 2013, Perzanowski et al. 2012). Dispersal by male bison has occurred up to several hundred km (Krasińska and Krasiński 2013). Dispersal by mixed groups is beginning to be observed in expanding populations, as the result of density-dependent intra-specific competition (Kowalczyk et al. 2013, Krasińska et al. 2014). The European Bison exhibits a well-developed and dynamic social organisation (Krasińska et al. 2014). Mixed groups of up to 20 individuals generally, including adult cows, two to three year-old sub-adults and calves are the basic social units. Males remain solitary or form bachelor groups of two to eight animals. The size and composition of mixed groups are dynamic and change seasonally, being the largest during rut and winter aggregations (Krasińska and Krasiński 2013). Daily activity is typical of large ruminants and includes foraging bouts (up to five hours) alternating with resting bouts (up to four hours) devoted primarily to rumination (Caboń-Raczyńska et al. 1987).

Palaeontological and archaeological findings indicate that the species distribution during the Holocene extended east from France to the Urals and the Northern Caucasus, and north from Bulgaria to southern Sweden, not including the Iberian Peninsula (Soubrier et al. 2016, Hofman-Kamińska et al. 2019). European Bison were historically distributed across Western and Eastern Europe (Węcek et al. 2017, Pucek et al. 2004). While the species was deemed to also occur in the northern Caucasus Mountains and foothills (Heptner et al. 1966), this area is not included in the IUCN European assessment range for this analysis.

As a generalist quadruped, the European Bison evolved to utilise open or mixed habitats; and with relatively high mobility in response to environmental drivers, there was likely substantial variation in local abundance and density, including extended absences at local to regional scales while the species was still distributed across the historic range. In short, the European Bison was likely patchily distributed and did not occur everywhere all the time within suitable habitat within its historic range. Extensive forest expansion occurred 12,000–8,000 Before Present (BP) concomitant with reduced open habitats available for large herbivores such as Bison and Aurochs. Humans expanded with the development of Neolithic agriculture (7,000-5,000 years BP) resulting in pressures on bison including hunting and land use conversion to agriculture.

The species became absent from most of Europe between 9,500 and 7,000 years BP, and after this period, recovered or recolonised, probably from the east (see Hofman-Kamińska et al. 2019). Since the 16^th century, European Bison persisted in the wild only through royal protection. By the 19^th century, free-living European Bison were limited to only the Białowieża Forest of northeast Poland and western Belarus, and the Caucasus Mountains (Pucek et al. 2004). By the early 20^th century, the species was increasingly imperilled in the wild, with the Lowland Bison subspecies becoming Extinct in the Wild in 1919, and the Caucasian Bison subspecies Extinct in the Wild by 1927 (Pucek et al. 2004). All extant populations are present as a result of reintroduction efforts.

Population viability
While the European Bison is no longer threatened by extinction, most free-living subpopulations are small and isolated. Small, isolated subpopulations are at risk from random catastrophic events and also lose genetic diversity more quickly than large subpopulations through the process of genetic drift, which in turn can decrease the viability of populations through an accumulation of inbreeding and loss of adaptive capacity. To mitigate the loss of genetic diversity in these isolated subpopulations, bison population viability analyses have suggested increasing subpopulation size where possible, and otherwise restoring effective gene flow among subpopulations and managing under a meta-population framework, where gene flow can be restored either through the restoration of natural movements between populations or through the translocation of animals (or gametes) among populations (Daleszczyk and Bunevich 2009, Hartway et al. 2019).

Conservation planning
In 2004, the IUCN-SSC-BSG published a report entitled “European Bison Status Survey and Conservation Action Plan” (Pucek et al. 2004). With the free-living population growing from 1,848 in 2003 to 6,244 in 2019, it is clearly time to undertake a new collaborative multi-stakeholder conservation planning process to produce an update to the 2004 CAP that includes a long-term conservation action plan with a very strong scientific basis and actionable consensus. Key issues needing to be examined include climate and environmental change, science advances and needs, increased interest in restoration programs involving large mammals, meta-population dynamics, conservation genetics (including the prevailing emphasis on separation of the Lowland (B. b. bonasus) and Caucasian (Bison bonasus bonasus x B. b. caucasicus) genetic lines amongst free-living subpopulations), disease ecology, habitat availability and shifting land use practices, restoration and translocation priorities, human dimensions, integrated in situ and ex situ management, and European Union and variable national and legal and policy status. The IUCN SSC BSG is formally partnering with the IUCN SSC Conservation Planning Specialist Group and multiple European wildlife conservation organisations to undertake collaborative conservation planning to produce an updated IUCN CAP that will serve as an innovative, efficient and effective milestone for its potential to empower new initiatives and result in better alignment of multi-national conservation strategies and actions.

Science needs
There is a critical need to enhance levels of collaborative and comparative science. Enhancing the effectiveness and sustainability of restoration activities should include testing of alternative hypotheses about landscape ecology, analysing habitat availability and suitability for optimal restoration designs, and comparative analyses of population viability and potential meta-population management strategies (see Daleszczyk and Bunevich 2009; Hartway et al. 2020; Kerley et al. 2012, 2020). Comparative analyses of the effects of selective culling and supplemental feeding will be important for improving the efficiency and effectiveness of local conservation management. Also needed are comparative analyses of bison ecology across the historic range (e.g. population ecology, metapopulation macrophysiology, foraging ecology, competition with sympatric wild ungulates, ecological cascades, ethology, etc.), comprehensive disease and parasitology monitoring, and innovative social science that addresses the human dimensions of bison recovery.

Adaptive management
Achieving the full ecological recovery of the European Bison conservation will require the collaboration of researchers, managers, and policymakers to develop and implement science-based adaptive management (Kerley and Knight 2010). There is a need to institutionalise evidence-based capacity to learn and adjust management as needed to restore bison to optimal habitats that secure the needs of the species throughout the year and spacious enough to maintain viable populations (Samojlik et al. 2019). It is very important to adaptively manage for an effective and efficient balance of supplementary feeding and culling with conservation of the full extent of the species naturally evolved ecology. Adaptive management can also serve as a framework to restore large heterogeneous landscapes that include forests, meadows and open habitats for both existing and future bison herds, thereby potentially lowering the expense of supplementary feeding when introducing to suitable habitats; to gain and employ an improved understanding of the human dimensions of bison recovery and thereby enhance active social support that includes financial and habitat commitments; and to strive for effective long-term genetic conservation and population viability by establishing sufficiently large meta-populations that link smaller isolated populations across regional geographic ranges.