Fertility Projections in a European Context: A Survey of Current Practices among Statistical Agencies

Projection studies have often focused on mortality and, more recently, migration. Fertility is less studied, although even small changes can have significant repercussions for the size and age structure of future populations. Across Europe, there is no consensus on how fertility is best projected. In this article, we identify different approaches used to project fertility among statistical agencies in Europe and provide an assessment of the different approaches according to the producers themselves. Data were collected using a mixed-method approach. First, European statistical agencies answered a questionnaire regarding fertility projection practices. Second, an in-depth review of select countries was performed. Most agencies combine formal models with expert opinion. While many attempt to maximise the use of relevant inputs, there is more variation in the detail of outputs, with some agencies unable to account for changing age patterns. In a context of limited resources, most are satisfied with their approaches, though some are assessing alternative methodologies to improve accuracy and increase transparency. This study highlights the diversity of approaches used in fertility projections across Europe. Such knowledge may be useful to statistical agencies as they consider, test and implement different approaches, perhaps in collaboration with other agencies and the wider scientific community.

Alternative scenarios of the demographic development of rural Russia: analysis and forecast

The purpose of the study is to discuss the alternative scenarios of the demographic development of rural Russia. The Covid-19 coronavirus pandemic has changed the demographic situation in Russia: mortality and natural population decline increased, while the birth rate decreased. Ba-sed on the cohort-component method, we projected the rural population size and age structure for the period 2024-2049. Six alternative scenarios were developed: three with zero migration (without taking into account the impact of migration changes on the rural population) and three with migration. Therefore, the migration outflow coefficient was included in the three forecasting scenarios. However, the inflow of some urban population to the countryside is not ruled out. The results show that the population of rural Russia will decrease from 37.3 million (2019) to 29.6–33.1 million people (2049). The age structure of the population will change, the demogra-phic aging of rural areas will continue.

Size-age differences in the bioecology of Mesobuthus eupeus (c.l. koch, 1839) (arachnida, scorpiones, buthidae) in Azerbaijan

The biotopical distribution, size and age structure of the population, nocturnal activity rhythm and feeding of the mottled scorpion (Mesobuthus eupeus) were studied. The research was conducted on the left bank of the Pirsagat river (Shirvan plain, Istern Azerbaijan). All discovered individuals of scorpions were divided into 5 size and age groups by the length of the metasome. The biotopical distribution of the mottled scorpion had a pronounced aggregated character with the formation of local clusters (settlements) in which 5 types of ratios of size and age groups were identified. It was found that individuals of II groups and I have unimodal, III and IV groups bimodal, and V group trimodal character of the rhythm of nocturnal activity. As the size of scorpions increases, the breadth of the nutrition spectrum increases, and the intensity of nutrition decreases. The index of electivity in II groups and I had negative values, and from III to V groups for some taxa of preys positive values. Representatives of the orders Isopoda (Crustacea), Aranei (Arachnida), Hymenoptera and Lepidoptera (Insecta) play a leading role in the nutrition of individuals of all size- age groups. As the size of scorpions increases, the proportion of members of the orders Hymenoptera, Blattodea and Collembola in their diet decreases. Representatives of the orders Coleoptera and Orthoptera are noted in the diet of scorpions from group III to V groups. Representatives of the orders Pulmonata (Gastropoda), Lumbricidae (Oligochaeta), Scolopendromorpha (Chilopoda), and Solifugae (Arachnida) are present in the diet only in individuals of IV and V groups.

Combined salinity and acidity stressors alter Daphnia magna population growth and structure under severe absence of photoperiod

Although natural and anthropogenic influences affect freshwater ecosystems globally at unprecedented levels, the effects of co-occurring physico-chemical stress on zooplankton phenotypic plasticity under extreme conditions remain understudied.We exposed a laboratory-raised clonal population of Daphnia magna to different stress levels of acidity and salinity undergoing complete constant light over 30 days. Overall, population size and age structure at day 10 considerably differed between specific stress contexts. All populations expanded compared to the starting population on day 1. On day 30, overall, population size increased but showed significant differences between treatment groups. Surprisingly, Daphnia performed better under combined stress of salinity and acidity than under acidity alone as the extra salinity in the medium may have counterbalanced sodium loss caused by lower pH. Our results reveal a considerable degree of differential reproductive and ontogenetic plasticity in response to combined stressors under disrupted photoperiod. Exposure to constant light led to increased population size, which may be a result of supercharged ion regulation that enables zooplankton to survive better under specific levels of extreme environmental change and adverse chemical stress. Our findings merit further molecular investigation of phenotypic plasticity of the congeners across severe combined stress conditions.

How the population of the Republic of Azerbaijan is ageing: causes and potential for social and economic development

The article deals with the trends of population ageing in the Republic of Azerbaijan. The author considers the stages of change of population size and age structure in the 20th and the 21st centuries as a result of historical evolution of birth rate and death rate. Based on the analysis of fertility trends and life expectancy, it is shown that the decline in fertility has so far been the most important factor in the population ageing, whereas the decline in the mortality in older ages is only beginning to contribute to this process. It is emphasized that anomalies in the sex ratio at birth lead to accelerated ageing of the population. The gradual ageing and reduction of the share of the working-age population, as well as the growth of the dependency ratio and the exhaustion of the potential of the first demographic dividend, are also analysed in the paper.