Despite the fact that urban areas have existed for millennia, no single, universal, supranational, and fully accepted definition of a city/town has been developed to date. The aim of this article is to review the criteria for identifying cities/towns in the world and their spatial differentiation. 233 territorial entities that are sovereign states or territories belonging to other states were surveyed. The analysis was based on a query from a list provided by the Department of Economic and Social Affairs of the United Nations Population Division, which contains the definitions of cities/towns adopted by individual countries or territories when collecting data in censuses. The research carried out shows that singleor multicriteria definitions, referring to quantitative or (and) qualitative elements from the group of legal-administrative, demographic, infrastructural-spatial, and functional criteria, are most often used to distinguish cities/towns from villages. More than half of the surveyed territorial entities use only one criterion mentioned, and this is usually a legal-administrative criterion or a demographic criterion. In the process of identifying cities/towns, just over two-fifths of the surveyed entities apply a minimum population threshold (as the only or one of many criteria), set most often at 2,000 or 5,000 inhabitants. East Africa is the most diverse region in the world in terms of the criteria adopted, while Central Asia, Australia, and New Zealand are the least.

The phenomenon of mass death of mussels in the Rusałka reservoir in Poznań took place in July 2018. As a result of this incident, the Unionidae population has been depleted. The number of dead mussels was counted, which floated around the banks and in the water. A total of approximately 5,500 deaths were found. Due to the scale of the phenomenon, the analysis of water quality was carried out by the Voivodeship Inspectorate for Environmental Protection in Poznań. Four samples of water were taken from different depths of the reservoir to perform physico-chemical and biological analyses. Two profiles, oxygen and temperature, were made in the deepest place of the Rusałka reservoir. There was a presence of hydrogen sulphide at the 5-meter depth of the reservoir. Additionally, oxygen concentration decreased strongly with depth to total deoxidation (< 0.50 mg·l-1O2 from 5 meters depth to the bottom). Furthermore, the average air temperatures in May 2018, in Poznań, were more than 3°C higher than in 2017 and 2016. In June and July, temperatures increased on average by 1 and 2°C compared to the previous. It was shown that the mass death of mussels was probably the result of the interaction of high temperature, a lack of oxygen, and the presence of hydrogen sulphide. It is not possible to clearly indicate only one factor that led to this phenomenon.

The article discusses the issue of attitudes of the Samburu ethnic group towards ’conservancies’ as the form of nature protection. The exploratory interviews (n = 12) were conducted among representatives of the Samburu community in northern Kenya. The aim of the research was to identify how Samburu perceive conservancies, considering current and expected consequences resulting from the development of this conservation form. The results show that the members of the Samburu community recognize the value of conservancies mainly through the economic benefits (gainful employment), as well as nature protection which is consistent with their religious values system (animism). However, the development of conservancies implying regulated access to natural resources (pasturelands) is seen as the real threat to their traditional pastoral culture. The attitudes of the local communities manifest a lack of trust in the management entities of the conservancies in the context of growing tensions between tribes over access to pasturelands. Consequently, prolonged droughts (climate change) may lead to a radical decrease in support for the idea of nature protection among members of the Samburu tribal elders.

The main purpose of this article is to present how geographical names reflect the specificity of the region. The onimic inquiring sight contains over 1000 microtoponyms that were collected during the geographical exploration from 2011 to 2017 in the Wręczyca Wielka community near Kłobuck, in the north of the Silesian Province. During the analysis of the above-mentioned toponomastic inquiry sight, the author used all information which were received from respondents (mainly from representatives of the oldest and middle generation) during informal conversations with the focus method. The first part of the text is devoted to the presentation of the basic methodological solutions and previous research. In the second part of this article, on the basis of detailed analysis of the geographical names of the Wręczyca Wielka community, the elements of environment and cultural factors captured in the geographical names, are presented. The microtoponyms reflect the specificity of the Wręczyca Wielka community because they archive data related to the natural and anthropogenic characteristics of the region. These record information, i.a. about: poorly diverse topography, underdeveloped hydrographic network, high degree of afforestation, iron mining, as well as old national relations.