Social capital research evaluates how individuals preserve social ties and access to diverse material and non-material resources. Material and other resources, and access to these, is embedded in networks and relationships, and these are under considerable strain in times of war. Specific social categories become more vulnerable, with an ever-increasing number of low-income households and internally displaced people. This paper focuses on empirical findings from five nationwide surveys conducted in Ukraine before the full-scale invasion (2019–2021) and after (2024–2026). The data demonstrates significant changes in the structures of social capital in national level samples, and in specific groups. Also, the data provides the evidence of a more comprehensive transformation of the structure of social capital in wartime Ukraine, with emerging and increasing social inequalities in Ukrainian society at large, and along age, and income divides as well as internal displacement experience covered by other surveys. By using multi wave data, the paper allows for modelling the further political and economic impact of social capital transformation. Keywords: social capital, war, multi-wave survey research, Ukraine

Russia’s full-scale invasion of Ukraine has unfolded alongside a deep decentralisation reform that transferred greater resources and authority to local communities. As a result, the local level has become a key arena in which different forms of uncertainty – security-related, institutional, social, and demographic – intersect. Communities simultaneously face large-scale internal displacement, growing social diversity, and changing models of governance. This paper analyses how social capital – understood as networks of trust, cooperation, and mutual support – shapes community cohesion under these conditions. Empirically, the study draws on data collected in 2025 in nine communities. The dataset includes 18 focus group discussions with community members – including representatives of different ethnic and religious groups, internally displaced persons, and veterans – as well as 28 semi-structured interviews with representatives of local self-government, civil society organisations, and local business. This design allows for combining the perspectives of diverse social groups with those of institutional actors and for analysing how communities work with social diversity in the context of war. Theoretically, social capital is conceptualised as a combination of bonding ties within social groups, bridging ties between groups, and linking ties between citizens and local institutions. The analysis shows that the war has significantly transformed these forms of social capital, reshaping patterns of interaction between local residents, IDPs, veterans, and religious communities. Decentralisation has provided communities with institutional and financial instruments to respond to crises, coordinate assistance, and involve residents in public decision-making. At the same time, case studies from ethnically diverse border communities, religiously mixed towns, and communities hosting large numbers of IDPs demonstrate that the outcomes of these institutional changes largely depend on the quality of local governance and on how communities engage with social diversity through communication, participation, and everyday practices of interaction.

Forced migration is intrinsically linked to profound uncertainty, frustration, and the depletion of "mental power" required for successful adaptation. For Ukrainian war refugees in Europe, the integration process is often hindered by alienation and a lack of informational resources. While host-country policies primarily focus on providing structural support, such as financial aid and language training, they frequently overlook the socio-behavioral mechanisms that facilitate or impede a refugee’s entry into the new society. This study employs a social cohesion framework to re-evaluate the relationship between bonding and bridging capital. Traditionally, integration models influenced by Robert Putnam (2000) suggest a tension between these two forms, warning that strong bonding within refugee groups may "encapsulate" them, leading to social isolation. However, by incorporating James Coleman’s (1988) functionalist conceptualization of social capital, this research views intra-group ties as a vital resource for rational actors. Coleman emphasizes that social capital consists of social-structural resources, such as the "social closure" of networks, that facilitate action. In the refugee context, these closed bonding networks provide the norms, trust, and mutual obligations necessary to navigate high-stakes uncertainty. The study proposes and tests an alternative hypothesis: that stronger bonding among refugees actually enhances their capacity for bridging to the host community. The causal mechanism suggests that these networks provide the emotional and informational stability needed to reduce the psychological costs of navigating a foreign environment. Rather than acting as a barrier, the support provided by compatriot networks acts as a safety net, empowering refugees to engage with the broader environment as a resilient group rather than as isolated individuals. To empirically test this, the research utilizes a trust game experiment. This behavioral approach allows for the measurement of trust and reciprocity - the "currency" of social capital - within and between groups. By analyzing how internal cohesion affects the willingness to trust external actors, the study aims to demonstrate that intra-group bonding is a functional prerequisite for successful adaptation. Ultimately, the findings suggest that integration policies should move beyond seeing refugee self-organization as a risk, recognizing it instead as a strategic asset that accelerates social and economic inclusion.