Nighttime lights represent the result of satellite observation of the artificial lighting of human activities on the Earth from space during the night, which provides the excellent opportunity to determine their position, pattern, density, and spatial distribution. Such data have a high detail spatial and temporal resolution, which opens a wide range of possibilities for quantitative and qualitative analysis. In this paper, nighttime lights are used as a highly accurate dataset for indirect tracking of changes in temporal and spatial patterns of population distribution and activity in Serbia. Two indicators were applied-Lighted area and Sum of lights. They are calculated for local government units in Serbia, for 2015 and period 2015-2019. The results of the conducted analysis follow the conclusions of the existing knowledge on population distribution based on the official statistical data. Areas with a high share of lighted areas are dominantly urban and the most populated, while traditionally depopulated areas are with a low share of lighted areas. Sum of lights highlighted the distinction between developed and populated north and depressive and depopulated south of Serbia. General conclusion is that ?dark has fallen in Serbia?, not only in peripheral and rural parts of the country, but in the smaller urban centers as well, and it is steadily spreading toward bigger urban areas. With nighttime lights application, this kind of process in terms of spatial disparities, its scope and dynamics can be easily identified, analyzed, and monitored.

This paper examines the issue of traditionally underdeveloped areas of Serbia, with special emphasis on development trends of the south, south-east and south-west areas of Central Serbia. The observed area is represented through a continuous time and space zone which includes rural, hilly-mountainous, border areas and the contact zone with the AP Kosovo and Metohija, including 22 municipalities, the majority of which belong to the so-called traditionally underdeveloped municipalities, that is, those that have had this status for a few decades. For the purpose of monitoring development trends, the indicators of the settlement structure, demographic and socio-economic characteristics and the level of development of the observed municipalities were used. Then, an evaluation and comparison to the national average were carried out. The presented results show a deviation and significant lagging behind of almost all parameters for the analysed municipalities in the period since 2002 until the present day, which indicates that the several-decade-long gap is still being intensified. A cluster analysis was performed for the typology of observed municipalities in order to determine the level of undevelopment and socio-economic marginalization.

Rural areas have been usually observed through agriculture; however, today, it is broadened with various activities. In Serbia, it has been characterized by unbalanced development, which has led to a declining vitality and depopulation. The main goal of this research is detection of seasonally activated rural areas in Serbia, expressed through the population fluctuation, temporary settlement, or occasional use of residential and economic facilities, and identification of spatial patterns of seasonal use. This research applied an innovative proxy—nighttime lights (NTL)—as a complementary tool to statistical analyses, which are conducted in the GIS environment. The calculation encompassed two seasonality coefficients: one based on the NTL and the second based on statistical data on tourist turnover. The spatial frame applies settlement level and micro level (pixels), while temporal includes monthly values for the period 2015–2019. The obtained results highlight tourist activity as the main cause of seasonal activation of rural areas. The largest seasonal fluctuations were registered in mountain areas and spa resorts. For mountain areas, the highest seasonality is in the winter months (peak—January/February), and lowest is in the summer season. The seasonal character of spa centers indicates the similar trend, generally less pronounced (peak—January), however, with higher seasonality during the summer.

Decentralization is a globally accepted concept of separation, the diversity of structures within the political system, the transfer of resources, activities, and powers in the decision-making process, and the division of tasks from the central government to lower authorities. It is implemented in both developed and developing countries, with different aims and consequences. In Serbia, the urban-centric development model and centralized governance caused rural settlements to become non-viable, and services and opportunities were deprived. This research has been undertaken in order to provide a deeper understanding of the territorial aspect of decentralization in Serbia and how it affects rural areas. It strives to offer a methodological framework for the identification of central settlements in rural areas of Serbia that will serve as a focal point for settlements networking in order to facilitate the spatial integration of rural areas and governance at the local level. This research encompasses (i) the identification of rural nodes as bearers of balanced governance and spatial development; (ii) the delimitation of their gravity sphere; and (iii) the determination of the relationship between settlement organization models and decentralization in Serbia. The research results indicate that identified rural nodes can be valuable to developing a holistic understanding of rural issues, supporting a bottom-up approach and regional disparities mitigation.