Urban tree diversity plays a crucial role in enhancing the resilience of cities by contributing to ecosystem services such as mitigating the effects of land degradation, combating urban heat islands, improving air quality, and fostering biodiversity habitats. A diverse tree population enhances resilience to vulnerabilities related to climatic stress, disease, and habitat loss by promoting stability, adaptability, and efficiency within the ecosystem. Little is known about urban tree diversity in Serbia; therefore, this study examines the diversity of tree species in the City of Niš, Serbia, to assess its implications for urban resilience and biodiversity preservation in the context of land-use change. Using the Shannon Diversity Index, we quantify species richness and evenness across both central and suburban zones of the city. The results are benchmarked against similar indices in five other European cities to assess how patterns of urban tree distribution vary under different urbanisation pressures. The study reveals that tree diversity is markedly lower in the city centre than in peripheral areas, highlighting spatial inequalities in green infrastructure that may accelerate biodiversity loss due to compact urban development. These findings demonstrate how urban expansion and infrastructure density contribute to ecological fragmentation, potentially leading to long-term effects on ecosystem services. This study emphasises the strategic importance of integrating greenery diversity into urban and landscape planning, particularly in rapidly growing urban centres in Southeastern Europe. This research contributes to the existing body of literature, providing a deeper understanding of the interdependencies between urban tree diversity, land degradation, and biodiversity loss, offering data-driven insights. This enables urban planners, landscape architects, and policy advisors to make informed decisions about street tree diversity and green city infrastructure, contributing to the development of sustainable cities.

In recent decades, cities have faced numerous problems related to the accelerated process of urbanization, which leads to ecological, spatial and social consequences. At the same time, globalization destroyed productive activities and created structural problems related to unemployment. For these reasons, cities are trying to attract new and growing industries that will provide jobs and enable the physical and economic regeneration of cities. One of the activities that increases employment and enables the urban regeneration of certain city zones is tourism. Urban tourism at the end of the 20th and beginning of the 21st century, with the process of globalization and the use of shorter vacations by tourists, experienced an expansion in the number of visitors, as well as the number of urban destinations. Urban destinations, as powerful financial, traffic, political, trade, etc. centers, in addition to cultural, architectural, construction, artistic, historical and environmental heritage, provide diversity and quality of tourist offer, completed by organizing congresses, professional gatherings, sports fairs, etc. Large world agglomerations, as the most important destinations of urban tourism, are visited annually by several million tourists.

This cross-country study examines how higher education institutions collaborate with government, industry, and civil society to promote the European Green Deal and Just Transition initiatives. Framed within the quadruple helix (QH) model, the research investigates emerging partnerships and the integration of green policies across six European countries: Bulgaria, Cyprus, France, Greece, Serbia, and Spain. Special emphasis is placed on the strategic role of universities in advancing the environmental, social, and economic dimensions of sustainability through their initiatives. Drawing on 30 semi-structured interviews with key stakeholders, including local public officials, academics, entrepreneurs, students, and unemployed youth, the study uncovers a growing alignment between academic initiatives and national sustainability agendas. While the extent of policy integration and collaboration varies, the findings underscore the importance of universities in shaping environmental awareness, fostering green innovation, and advancing multi-actor partnerships. The study contributes to the theoretical discourse on the QH model by applying it to the field of green transition policy and offers practical recommendations for enhancing the role of universities in sustainability-oriented governance and education.

This paper investigates the impact of demographic changes on regional disparities within the European Union. The analysis focuses on key demographic trends—population ageing, low fertility rates, and migration flows—and their long-term implications for labor markets, economic growth, and the sustainability of social systems across EU regions. Using Eurostat data for 169 NUTS2 regions for 2022 and 2023, the study applies descriptive statistics, correlation analysis, and multiple regression models to quantify the effects of life expectancy, fertility rates, and educational attainment on GDP growth and employment in knowledge-intensive and high-tech sectors. Findings indicate that regions with higher shares of highly educated labor and favorable demographic profiles tend to achieve greater economic resilience and competitiveness. In contrast, demographic decline and outmigration continue to deepen structural disparities, particularly in rural and less developed regions. The results underscore the importance of integrated EU policies aimed at addressing demographic challenges while promoting regional cohesion through investment in human capital, innovation, and infrastructure. By highlighting the critical role of demographic factors in shaping regional development, this study contributes to the discourse on designing effective policies to foster sustainable and inclusive growth within the European Union.